Add default file_driver if missing
[ganeti-github.git] / lib / cmdlib / instance.py
index b5dc099..e922800 100644 (file)
 
 import OpenSSL
 import copy
-import itertools
 import logging
-import operator
 import os
-import time
 
 from ganeti import compat
 from ganeti import constants
@@ -41,50 +38,34 @@ from ganeti import netutils
 from ganeti import objects
 from ganeti import opcodes
 from ganeti import pathutils
-from ganeti import qlang
 from ganeti import rpc
 from ganeti import utils
-from ganeti import query
-
-from ganeti.cmdlib.base import NoHooksLU, LogicalUnit, _QueryBase, \
-  ResultWithJobs, Tasklet
-
-from ganeti.cmdlib.common import INSTANCE_ONLINE, INSTANCE_DOWN, \
-  INSTANCE_NOT_RUNNING, CAN_CHANGE_INSTANCE_OFFLINE, _CheckNodeOnline, \
-  _ShareAll, _GetDefaultIAllocator, _CheckInstanceNodeGroups, \
-  _LoadNodeEvacResult, _CheckIAllocatorOrNode, _CheckParamsNotGlobal, \
-  _IsExclusiveStorageEnabledNode, _CheckHVParams, _CheckOSParams, \
-  _GetWantedInstances, _CheckInstancesNodeGroups, _AnnotateDiskParams, \
-  _GetUpdatedParams, _ExpandInstanceName, _FindFaultyInstanceDisks, \
-  _ComputeIPolicySpecViolation, _ComputeIPolicyInstanceViolation, \
-  _CheckInstanceState, _ExpandNodeName
-from ganeti.cmdlib.instance_utils import _AssembleInstanceDisks, \
-  _BuildInstanceHookEnvByObject, _GetClusterDomainSecret, \
-  _BuildInstanceHookEnv, _NICListToTuple, _NICToTuple, _CheckNodeNotDrained, \
-  _RemoveDisks, _StartInstanceDisks, _ShutdownInstanceDisks, \
-  _RemoveInstance, _ExpandCheckDisks
-
-import ganeti.masterd.instance
-
-
-_DISK_TEMPLATE_NAME_PREFIX = {
-  constants.DT_PLAIN: "",
-  constants.DT_RBD: ".rbd",
-  constants.DT_EXT: ".ext",
-  }
 
+from ganeti.cmdlib.base import NoHooksLU, LogicalUnit, ResultWithJobs
+
+from ganeti.cmdlib.common import INSTANCE_DOWN, \
+  INSTANCE_NOT_RUNNING, CAN_CHANGE_INSTANCE_OFFLINE, CheckNodeOnline, \
+  ShareAll, GetDefaultIAllocator, CheckInstanceNodeGroups, \
+  LoadNodeEvacResult, CheckIAllocatorOrNode, CheckParamsNotGlobal, \
+  IsExclusiveStorageEnabledNode, CheckHVParams, CheckOSParams, \
+  AnnotateDiskParams, GetUpdatedParams, ExpandInstanceName, \
+  ComputeIPolicySpecViolation, CheckInstanceState, ExpandNodeName
+from ganeti.cmdlib.instance_storage import CreateDisks, \
+  CheckNodesFreeDiskPerVG, WipeDisks, WipeOrCleanupDisks, WaitForSync, \
+  IsExclusiveStorageEnabledNodeName, CreateSingleBlockDev, ComputeDisks, \
+  CheckRADOSFreeSpace, ComputeDiskSizePerVG, GenerateDiskTemplate, \
+  StartInstanceDisks, ShutdownInstanceDisks, AssembleInstanceDisks
+from ganeti.cmdlib.instance_utils import BuildInstanceHookEnvByObject, \
+  GetClusterDomainSecret, BuildInstanceHookEnv, NICListToTuple, \
+  NICToTuple, CheckNodeNotDrained, RemoveInstance, CopyLockList, \
+  ReleaseLocks, CheckNodeVmCapable, CheckTargetNodeIPolicy, \
+  GetInstanceInfoText, RemoveDisks, CheckNodeFreeMemory, \
+  CheckInstanceBridgesExist, CheckNicsBridgesExist, CheckNodeHasOS
 
-_DISK_TEMPLATE_DEVICE_TYPE = {
-  constants.DT_PLAIN: constants.LD_LV,
-  constants.DT_FILE: constants.LD_FILE,
-  constants.DT_SHARED_FILE: constants.LD_FILE,
-  constants.DT_BLOCK: constants.LD_BLOCKDEV,
-  constants.DT_RBD: constants.LD_RBD,
-  constants.DT_EXT: constants.LD_EXT,
-  }
+import ganeti.masterd.instance
 
 
-#: Type description for changes as returned by L{ApplyContainerMods}'s
+#: Type description for changes as returned by L{_ApplyContainerMods}'s
 #: callbacks
 _TApplyContModsCbChanges = \
   ht.TMaybeListOf(ht.TAnd(ht.TIsLength(2), ht.TItems([
@@ -93,68 +74,6 @@ _TApplyContModsCbChanges = \
     ])))
 
 
-def _CopyLockList(names):
-  """Makes a copy of a list of lock names.
-
-  Handles L{locking.ALL_SET} correctly.
-
-  """
-  if names == locking.ALL_SET:
-    return locking.ALL_SET
-  else:
-    return names[:]
-
-
-def _ReleaseLocks(lu, level, names=None, keep=None):
-  """Releases locks owned by an LU.
-
-  @type lu: L{LogicalUnit}
-  @param level: Lock level
-  @type names: list or None
-  @param names: Names of locks to release
-  @type keep: list or None
-  @param keep: Names of locks to retain
-
-  """
-  assert not (keep is not None and names is not None), \
-    "Only one of the 'names' and the 'keep' parameters can be given"
-
-  if names is not None:
-    should_release = names.__contains__
-  elif keep:
-    should_release = lambda name: name not in keep
-  else:
-    should_release = None
-
-  owned = lu.owned_locks(level)
-  if not owned:
-    # Not owning any lock at this level, do nothing
-    pass
-
-  elif should_release:
-    retain = []
-    release = []
-
-    # Determine which locks to release
-    for name in owned:
-      if should_release(name):
-        release.append(name)
-      else:
-        retain.append(name)
-
-    assert len(lu.owned_locks(level)) == (len(retain) + len(release))
-
-    # Release just some locks
-    lu.glm.release(level, names=release)
-
-    assert frozenset(lu.owned_locks(level)) == frozenset(retain)
-  else:
-    # Release everything
-    lu.glm.release(level)
-
-    assert not lu.glm.is_owned(level), "No locks should be owned"
-
-
 def _CheckHostnameSane(lu, name):
   """Ensures that a given hostname resolves to a 'sane' name.
 
@@ -344,264 +263,9 @@ def _CheckForConflictingIp(lu, ip, node):
   return (None, None)
 
 
-def _CheckRADOSFreeSpace():
-  """Compute disk size requirements inside the RADOS cluster.
-
-  """
-  # For the RADOS cluster we assume there is always enough space.
-  pass
-
-
-def _WaitForSync(lu, instance, disks=None, oneshot=False):
-  """Sleep and poll for an instance's disk to sync.
-
-  """
-  if not instance.disks or disks is not None and not disks:
-    return True
-
-  disks = _ExpandCheckDisks(instance, disks)
-
-  if not oneshot:
-    lu.LogInfo("Waiting for instance %s to sync disks", instance.name)
-
-  node = instance.primary_node
-
-  for dev in disks:
-    lu.cfg.SetDiskID(dev, node)
-
-  # TODO: Convert to utils.Retry
-
-  retries = 0
-  degr_retries = 10 # in seconds, as we sleep 1 second each time
-  while True:
-    max_time = 0
-    done = True
-    cumul_degraded = False
-    rstats = lu.rpc.call_blockdev_getmirrorstatus(node, (disks, instance))
-    msg = rstats.fail_msg
-    if msg:
-      lu.LogWarning("Can't get any data from node %s: %s", node, msg)
-      retries += 1
-      if retries >= 10:
-        raise errors.RemoteError("Can't contact node %s for mirror data,"
-                                 " aborting." % node)
-      time.sleep(6)
-      continue
-    rstats = rstats.payload
-    retries = 0
-    for i, mstat in enumerate(rstats):
-      if mstat is None:
-        lu.LogWarning("Can't compute data for node %s/%s",
-                      node, disks[i].iv_name)
-        continue
-
-      cumul_degraded = (cumul_degraded or
-                        (mstat.is_degraded and mstat.sync_percent is None))
-      if mstat.sync_percent is not None:
-        done = False
-        if mstat.estimated_time is not None:
-          rem_time = ("%s remaining (estimated)" %
-                      utils.FormatSeconds(mstat.estimated_time))
-          max_time = mstat.estimated_time
-        else:
-          rem_time = "no time estimate"
-        lu.LogInfo("- device %s: %5.2f%% done, %s",
-                   disks[i].iv_name, mstat.sync_percent, rem_time)
-
-    # if we're done but degraded, let's do a few small retries, to
-    # make sure we see a stable and not transient situation; therefore
-    # we force restart of the loop
-    if (done or oneshot) and cumul_degraded and degr_retries > 0:
-      logging.info("Degraded disks found, %d retries left", degr_retries)
-      degr_retries -= 1
-      time.sleep(1)
-      continue
-
-    if done or oneshot:
-      break
-
-    time.sleep(min(60, max_time))
-
-  if done:
-    lu.LogInfo("Instance %s's disks are in sync", instance.name)
-
-  return not cumul_degraded
-
-
-def _ComputeDisks(op, default_vg):
-  """Computes the instance disks.
-
-  @param op: The instance opcode
-  @param default_vg: The default_vg to assume
-
-  @return: The computed disks
-
-  """
-  disks = []
-  for disk in op.disks:
-    mode = disk.get(constants.IDISK_MODE, constants.DISK_RDWR)
-    if mode not in constants.DISK_ACCESS_SET:
-      raise errors.OpPrereqError("Invalid disk access mode '%s'" %
-                                 mode, errors.ECODE_INVAL)
-    size = disk.get(constants.IDISK_SIZE, None)
-    if size is None:
-      raise errors.OpPrereqError("Missing disk size", errors.ECODE_INVAL)
-    try:
-      size = int(size)
-    except (TypeError, ValueError):
-      raise errors.OpPrereqError("Invalid disk size '%s'" % size,
-                                 errors.ECODE_INVAL)
-
-    ext_provider = disk.get(constants.IDISK_PROVIDER, None)
-    if ext_provider and op.disk_template != constants.DT_EXT:
-      raise errors.OpPrereqError("The '%s' option is only valid for the %s"
-                                 " disk template, not %s" %
-                                 (constants.IDISK_PROVIDER, constants.DT_EXT,
-                                  op.disk_template), errors.ECODE_INVAL)
-
-    data_vg = disk.get(constants.IDISK_VG, default_vg)
-    name = disk.get(constants.IDISK_NAME, None)
-    if name is not None and name.lower() == constants.VALUE_NONE:
-      name = None
-    new_disk = {
-      constants.IDISK_SIZE: size,
-      constants.IDISK_MODE: mode,
-      constants.IDISK_VG: data_vg,
-      constants.IDISK_NAME: name,
-      }
-
-    if constants.IDISK_METAVG in disk:
-      new_disk[constants.IDISK_METAVG] = disk[constants.IDISK_METAVG]
-    if constants.IDISK_ADOPT in disk:
-      new_disk[constants.IDISK_ADOPT] = disk[constants.IDISK_ADOPT]
-
-    # For extstorage, demand the `provider' option and add any
-    # additional parameters (ext-params) to the dict
-    if op.disk_template == constants.DT_EXT:
-      if ext_provider:
-        new_disk[constants.IDISK_PROVIDER] = ext_provider
-        for key in disk:
-          if key not in constants.IDISK_PARAMS:
-            new_disk[key] = disk[key]
-      else:
-        raise errors.OpPrereqError("Missing provider for template '%s'" %
-                                   constants.DT_EXT, errors.ECODE_INVAL)
-
-    disks.append(new_disk)
-
-  return disks
-
-
-def _ComputeDiskSizePerVG(disk_template, disks):
-  """Compute disk size requirements in the volume group
-
-  """
-  def _compute(disks, payload):
-    """Universal algorithm.
-
-    """
-    vgs = {}
-    for disk in disks:
-      vgs[disk[constants.IDISK_VG]] = \
-        vgs.get(constants.IDISK_VG, 0) + disk[constants.IDISK_SIZE] + payload
-
-    return vgs
-
-  # Required free disk space as a function of disk and swap space
-  req_size_dict = {
-    constants.DT_DISKLESS: {},
-    constants.DT_PLAIN: _compute(disks, 0),
-    # 128 MB are added for drbd metadata for each disk
-    constants.DT_DRBD8: _compute(disks, constants.DRBD_META_SIZE),
-    constants.DT_FILE: {},
-    constants.DT_SHARED_FILE: {},
-    }
-
-  if disk_template not in req_size_dict:
-    raise errors.ProgrammerError("Disk template '%s' size requirement"
-                                 " is unknown" % disk_template)
-
-  return req_size_dict[disk_template]
-
-
-def _CheckNodesFreeDiskOnVG(lu, nodenames, vg, requested):
-  """Checks if nodes have enough free disk space in the specified VG.
-
-  This function checks if all given nodes have the needed amount of
-  free disk. In case any node has less disk or we cannot get the
-  information from the node, this function raises an OpPrereqError
-  exception.
-
-  @type lu: C{LogicalUnit}
-  @param lu: a logical unit from which we get configuration data
-  @type nodenames: C{list}
-  @param nodenames: the list of node names to check
-  @type vg: C{str}
-  @param vg: the volume group to check
-  @type requested: C{int}
-  @param requested: the amount of disk in MiB to check for
-  @raise errors.OpPrereqError: if the node doesn't have enough disk,
-      or we cannot check the node
-
-  """
-  es_flags = rpc.GetExclusiveStorageForNodeNames(lu.cfg, nodenames)
-  nodeinfo = lu.rpc.call_node_info(nodenames, [vg], None, es_flags)
-  for node in nodenames:
-    info = nodeinfo[node]
-    info.Raise("Cannot get current information from node %s" % node,
-               prereq=True, ecode=errors.ECODE_ENVIRON)
-    (_, (vg_info, ), _) = info.payload
-    vg_free = vg_info.get("vg_free", None)
-    if not isinstance(vg_free, int):
-      raise errors.OpPrereqError("Can't compute free disk space on node"
-                                 " %s for vg %s, result was '%s'" %
-                                 (node, vg, vg_free), errors.ECODE_ENVIRON)
-    if requested > vg_free:
-      raise errors.OpPrereqError("Not enough disk space on target node %s"
-                                 " vg %s: required %d MiB, available %d MiB" %
-                                 (node, vg, requested, vg_free),
-                                 errors.ECODE_NORES)
-
-
-def _CheckNodesFreeDiskPerVG(lu, nodenames, req_sizes):
-  """Checks if nodes have enough free disk space in all the VGs.
-
-  This function checks if all given nodes have the needed amount of
-  free disk. In case any node has less disk or we cannot get the
-  information from the node, this function raises an OpPrereqError
-  exception.
-
-  @type lu: C{LogicalUnit}
-  @param lu: a logical unit from which we get configuration data
-  @type nodenames: C{list}
-  @param nodenames: the list of node names to check
-  @type req_sizes: C{dict}
-  @param req_sizes: the hash of vg and corresponding amount of disk in
-      MiB to check for
-  @raise errors.OpPrereqError: if the node doesn't have enough disk,
-      or we cannot check the node
-
-  """
-  for vg, req_size in req_sizes.items():
-    _CheckNodesFreeDiskOnVG(lu, nodenames, vg, req_size)
-
-
-def _CheckNodeVmCapable(lu, node):
-  """Ensure that a given node is vm capable.
-
-  @param lu: the LU on behalf of which we make the check
-  @param node: the node to check
-  @raise errors.OpPrereqError: if the node is not vm capable
-
-  """
-  if not lu.cfg.GetNodeInfo(node).vm_capable:
-    raise errors.OpPrereqError("Can't use non-vm_capable node %s" % node,
-                               errors.ECODE_STATE)
-
-
 def _ComputeIPolicyInstanceSpecViolation(
   ipolicy, instance_spec, disk_template,
-  _compute_fn=_ComputeIPolicySpecViolation):
+  _compute_fn=ComputeIPolicySpecViolation):
   """Compute if instance specs meets the specs of ipolicy.
 
   @type ipolicy: dict
@@ -611,7 +275,7 @@ def _ComputeIPolicyInstanceSpecViolation(
   @type disk_template: string
   @param disk_template: the disk template of the instance
   @param _compute_fn: The function to verify ipolicy (unittest only)
-  @see: L{_ComputeIPolicySpecViolation}
+  @see: L{ComputeIPolicySpecViolation}
 
   """
   mem_size = instance_spec.get(constants.ISPEC_MEM_SIZE, None)
@@ -649,531 +313,6 @@ def _CheckOSVariant(os_obj, name):
     raise errors.OpPrereqError("Unsupported OS variant", errors.ECODE_INVAL)
 
 
-def _CheckNodeHasOS(lu, node, os_name, force_variant):
-  """Ensure that a node supports a given OS.
-
-  @param lu: the LU on behalf of which we make the check
-  @param node: the node to check
-  @param os_name: the OS to query about
-  @param force_variant: whether to ignore variant errors
-  @raise errors.OpPrereqError: if the node is not supporting the OS
-
-  """
-  result = lu.rpc.call_os_get(node, os_name)
-  result.Raise("OS '%s' not in supported OS list for node %s" %
-               (os_name, node),
-               prereq=True, ecode=errors.ECODE_INVAL)
-  if not force_variant:
-    _CheckOSVariant(result.payload, os_name)
-
-
-def _CheckNicsBridgesExist(lu, target_nics, target_node):
-  """Check that the brigdes needed by a list of nics exist.
-
-  """
-  cluster = lu.cfg.GetClusterInfo()
-  paramslist = [cluster.SimpleFillNIC(nic.nicparams) for nic in target_nics]
-  brlist = [params[constants.NIC_LINK] for params in paramslist
-            if params[constants.NIC_MODE] == constants.NIC_MODE_BRIDGED]
-  if brlist:
-    result = lu.rpc.call_bridges_exist(target_node, brlist)
-    result.Raise("Error checking bridges on destination node '%s'" %
-                 target_node, prereq=True, ecode=errors.ECODE_ENVIRON)
-
-
-def _CheckNodeFreeMemory(lu, node, reason, requested, hypervisor_name):
-  """Checks if a node has enough free memory.
-
-  This function checks if a given node has the needed amount of free
-  memory. In case the node has less memory or we cannot get the
-  information from the node, this function raises an OpPrereqError
-  exception.
-
-  @type lu: C{LogicalUnit}
-  @param lu: a logical unit from which we get configuration data
-  @type node: C{str}
-  @param node: the node to check
-  @type reason: C{str}
-  @param reason: string to use in the error message
-  @type requested: C{int}
-  @param requested: the amount of memory in MiB to check for
-  @type hypervisor_name: C{str}
-  @param hypervisor_name: the hypervisor to ask for memory stats
-  @rtype: integer
-  @return: node current free memory
-  @raise errors.OpPrereqError: if the node doesn't have enough memory, or
-      we cannot check the node
-
-  """
-  nodeinfo = lu.rpc.call_node_info([node], None, [hypervisor_name], False)
-  nodeinfo[node].Raise("Can't get data from node %s" % node,
-                       prereq=True, ecode=errors.ECODE_ENVIRON)
-  (_, _, (hv_info, )) = nodeinfo[node].payload
-
-  free_mem = hv_info.get("memory_free", None)
-  if not isinstance(free_mem, int):
-    raise errors.OpPrereqError("Can't compute free memory on node %s, result"
-                               " was '%s'" % (node, free_mem),
-                               errors.ECODE_ENVIRON)
-  if requested > free_mem:
-    raise errors.OpPrereqError("Not enough memory on node %s for %s:"
-                               " needed %s MiB, available %s MiB" %
-                               (node, reason, requested, free_mem),
-                               errors.ECODE_NORES)
-  return free_mem
-
-
-def _GenerateUniqueNames(lu, exts):
-  """Generate a suitable LV name.
-
-  This will generate a logical volume name for the given instance.
-
-  """
-  results = []
-  for val in exts:
-    new_id = lu.cfg.GenerateUniqueID(lu.proc.GetECId())
-    results.append("%s%s" % (new_id, val))
-  return results
-
-
-def _GenerateDRBD8Branch(lu, primary, secondary, size, vgnames, names,
-                         iv_name, p_minor, s_minor):
-  """Generate a drbd8 device complete with its children.
-
-  """
-  assert len(vgnames) == len(names) == 2
-  port = lu.cfg.AllocatePort()
-  shared_secret = lu.cfg.GenerateDRBDSecret(lu.proc.GetECId())
-
-  dev_data = objects.Disk(dev_type=constants.LD_LV, size=size,
-                          logical_id=(vgnames[0], names[0]),
-                          params={})
-  dev_data.uuid = lu.cfg.GenerateUniqueID(lu.proc.GetECId())
-  dev_meta = objects.Disk(dev_type=constants.LD_LV,
-                          size=constants.DRBD_META_SIZE,
-                          logical_id=(vgnames[1], names[1]),
-                          params={})
-  dev_meta.uuid = lu.cfg.GenerateUniqueID(lu.proc.GetECId())
-  drbd_dev = objects.Disk(dev_type=constants.LD_DRBD8, size=size,
-                          logical_id=(primary, secondary, port,
-                                      p_minor, s_minor,
-                                      shared_secret),
-                          children=[dev_data, dev_meta],
-                          iv_name=iv_name, params={})
-  drbd_dev.uuid = lu.cfg.GenerateUniqueID(lu.proc.GetECId())
-  return drbd_dev
-
-
-def _GenerateDiskTemplate(
-  lu, template_name, instance_name, primary_node, secondary_nodes,
-  disk_info, file_storage_dir, file_driver, base_index,
-  feedback_fn, full_disk_params, _req_file_storage=opcodes.RequireFileStorage,
-  _req_shr_file_storage=opcodes.RequireSharedFileStorage):
-  """Generate the entire disk layout for a given template type.
-
-  """
-  vgname = lu.cfg.GetVGName()
-  disk_count = len(disk_info)
-  disks = []
-
-  if template_name == constants.DT_DISKLESS:
-    pass
-  elif template_name == constants.DT_DRBD8:
-    if len(secondary_nodes) != 1:
-      raise errors.ProgrammerError("Wrong template configuration")
-    remote_node = secondary_nodes[0]
-    minors = lu.cfg.AllocateDRBDMinor(
-      [primary_node, remote_node] * len(disk_info), instance_name)
-
-    (drbd_params, _, _) = objects.Disk.ComputeLDParams(template_name,
-                                                       full_disk_params)
-    drbd_default_metavg = drbd_params[constants.LDP_DEFAULT_METAVG]
-
-    names = []
-    for lv_prefix in _GenerateUniqueNames(lu, [".disk%d" % (base_index + i)
-                                               for i in range(disk_count)]):
-      names.append(lv_prefix + "_data")
-      names.append(lv_prefix + "_meta")
-    for idx, disk in enumerate(disk_info):
-      disk_index = idx + base_index
-      data_vg = disk.get(constants.IDISK_VG, vgname)
-      meta_vg = disk.get(constants.IDISK_METAVG, drbd_default_metavg)
-      disk_dev = _GenerateDRBD8Branch(lu, primary_node, remote_node,
-                                      disk[constants.IDISK_SIZE],
-                                      [data_vg, meta_vg],
-                                      names[idx * 2:idx * 2 + 2],
-                                      "disk/%d" % disk_index,
-                                      minors[idx * 2], minors[idx * 2 + 1])
-      disk_dev.mode = disk[constants.IDISK_MODE]
-      disk_dev.name = disk.get(constants.IDISK_NAME, None)
-      disks.append(disk_dev)
-  else:
-    if secondary_nodes:
-      raise errors.ProgrammerError("Wrong template configuration")
-
-    if template_name == constants.DT_FILE:
-      _req_file_storage()
-    elif template_name == constants.DT_SHARED_FILE:
-      _req_shr_file_storage()
-
-    name_prefix = _DISK_TEMPLATE_NAME_PREFIX.get(template_name, None)
-    if name_prefix is None:
-      names = None
-    else:
-      names = _GenerateUniqueNames(lu, ["%s.disk%s" %
-                                        (name_prefix, base_index + i)
-                                        for i in range(disk_count)])
-
-    if template_name == constants.DT_PLAIN:
-
-      def logical_id_fn(idx, _, disk):
-        vg = disk.get(constants.IDISK_VG, vgname)
-        return (vg, names[idx])
-
-    elif template_name in (constants.DT_FILE, constants.DT_SHARED_FILE):
-      logical_id_fn = \
-        lambda _, disk_index, disk: (file_driver,
-                                     "%s/disk%d" % (file_storage_dir,
-                                                    disk_index))
-    elif template_name == constants.DT_BLOCK:
-      logical_id_fn = \
-        lambda idx, disk_index, disk: (constants.BLOCKDEV_DRIVER_MANUAL,
-                                       disk[constants.IDISK_ADOPT])
-    elif template_name == constants.DT_RBD:
-      logical_id_fn = lambda idx, _, disk: ("rbd", names[idx])
-    elif template_name == constants.DT_EXT:
-      def logical_id_fn(idx, _, disk):
-        provider = disk.get(constants.IDISK_PROVIDER, None)
-        if provider is None:
-          raise errors.ProgrammerError("Disk template is %s, but '%s' is"
-                                       " not found", constants.DT_EXT,
-                                       constants.IDISK_PROVIDER)
-        return (provider, names[idx])
-    else:
-      raise errors.ProgrammerError("Unknown disk template '%s'" % template_name)
-
-    dev_type = _DISK_TEMPLATE_DEVICE_TYPE[template_name]
-
-    for idx, disk in enumerate(disk_info):
-      params = {}
-      # Only for the Ext template add disk_info to params
-      if template_name == constants.DT_EXT:
-        params[constants.IDISK_PROVIDER] = disk[constants.IDISK_PROVIDER]
-        for key in disk:
-          if key not in constants.IDISK_PARAMS:
-            params[key] = disk[key]
-      disk_index = idx + base_index
-      size = disk[constants.IDISK_SIZE]
-      feedback_fn("* disk %s, size %s" %
-                  (disk_index, utils.FormatUnit(size, "h")))
-      disk_dev = objects.Disk(dev_type=dev_type, size=size,
-                              logical_id=logical_id_fn(idx, disk_index, disk),
-                              iv_name="disk/%d" % disk_index,
-                              mode=disk[constants.IDISK_MODE],
-                              params=params)
-      disk_dev.name = disk.get(constants.IDISK_NAME, None)
-      disk_dev.uuid = lu.cfg.GenerateUniqueID(lu.proc.GetECId())
-      disks.append(disk_dev)
-
-  return disks
-
-
-def _CreateSingleBlockDev(lu, node, instance, device, info, force_open,
-                          excl_stor):
-  """Create a single block device on a given node.
-
-  This will not recurse over children of the device, so they must be
-  created in advance.
-
-  @param lu: the lu on whose behalf we execute
-  @param node: the node on which to create the device
-  @type instance: L{objects.Instance}
-  @param instance: the instance which owns the device
-  @type device: L{objects.Disk}
-  @param device: the device to create
-  @param info: the extra 'metadata' we should attach to the device
-      (this will be represented as a LVM tag)
-  @type force_open: boolean
-  @param force_open: this parameter will be passes to the
-      L{backend.BlockdevCreate} function where it specifies
-      whether we run on primary or not, and it affects both
-      the child assembly and the device own Open() execution
-  @type excl_stor: boolean
-  @param excl_stor: Whether exclusive_storage is active for the node
-
-  """
-  lu.cfg.SetDiskID(device, node)
-  result = lu.rpc.call_blockdev_create(node, device, device.size,
-                                       instance.name, force_open, info,
-                                       excl_stor)
-  result.Raise("Can't create block device %s on"
-               " node %s for instance %s" % (device, node, instance.name))
-  if device.physical_id is None:
-    device.physical_id = result.payload
-
-
-def _CreateBlockDevInner(lu, node, instance, device, force_create,
-                         info, force_open, excl_stor):
-  """Create a tree of block devices on a given node.
-
-  If this device type has to be created on secondaries, create it and
-  all its children.
-
-  If not, just recurse to children keeping the same 'force' value.
-
-  @attention: The device has to be annotated already.
-
-  @param lu: the lu on whose behalf we execute
-  @param node: the node on which to create the device
-  @type instance: L{objects.Instance}
-  @param instance: the instance which owns the device
-  @type device: L{objects.Disk}
-  @param device: the device to create
-  @type force_create: boolean
-  @param force_create: whether to force creation of this device; this
-      will be change to True whenever we find a device which has
-      CreateOnSecondary() attribute
-  @param info: the extra 'metadata' we should attach to the device
-      (this will be represented as a LVM tag)
-  @type force_open: boolean
-  @param force_open: this parameter will be passes to the
-      L{backend.BlockdevCreate} function where it specifies
-      whether we run on primary or not, and it affects both
-      the child assembly and the device own Open() execution
-  @type excl_stor: boolean
-  @param excl_stor: Whether exclusive_storage is active for the node
-
-  @return: list of created devices
-  """
-  created_devices = []
-  try:
-    if device.CreateOnSecondary():
-      force_create = True
-
-    if device.children:
-      for child in device.children:
-        devs = _CreateBlockDevInner(lu, node, instance, child, force_create,
-                                    info, force_open, excl_stor)
-        created_devices.extend(devs)
-
-    if not force_create:
-      return created_devices
-
-    _CreateSingleBlockDev(lu, node, instance, device, info, force_open,
-                          excl_stor)
-    # The device has been completely created, so there is no point in keeping
-    # its subdevices in the list. We just add the device itself instead.
-    created_devices = [(node, device)]
-    return created_devices
-
-  except errors.DeviceCreationError, e:
-    e.created_devices.extend(created_devices)
-    raise e
-  except errors.OpExecError, e:
-    raise errors.DeviceCreationError(str(e), created_devices)
-
-
-def _IsExclusiveStorageEnabledNodeName(cfg, nodename):
-  """Whether exclusive_storage is in effect for the given node.
-
-  @type cfg: L{config.ConfigWriter}
-  @param cfg: The cluster configuration
-  @type nodename: string
-  @param nodename: The node
-  @rtype: bool
-  @return: The effective value of exclusive_storage
-  @raise errors.OpPrereqError: if no node exists with the given name
-
-  """
-  ni = cfg.GetNodeInfo(nodename)
-  if ni is None:
-    raise errors.OpPrereqError("Invalid node name %s" % nodename,
-                               errors.ECODE_NOENT)
-  return _IsExclusiveStorageEnabledNode(cfg, ni)
-
-
-def _CreateBlockDev(lu, node, instance, device, force_create, info,
-                    force_open):
-  """Wrapper around L{_CreateBlockDevInner}.
-
-  This method annotates the root device first.
-
-  """
-  (disk,) = _AnnotateDiskParams(instance, [device], lu.cfg)
-  excl_stor = _IsExclusiveStorageEnabledNodeName(lu.cfg, node)
-  return _CreateBlockDevInner(lu, node, instance, disk, force_create, info,
-                              force_open, excl_stor)
-
-
-def _CreateDisks(lu, instance, to_skip=None, target_node=None):
-  """Create all disks for an instance.
-
-  This abstracts away some work from AddInstance.
-
-  @type lu: L{LogicalUnit}
-  @param lu: the logical unit on whose behalf we execute
-  @type instance: L{objects.Instance}
-  @param instance: the instance whose disks we should create
-  @type to_skip: list
-  @param to_skip: list of indices to skip
-  @type target_node: string
-  @param target_node: if passed, overrides the target node for creation
-  @rtype: boolean
-  @return: the success of the creation
-
-  """
-  info = _GetInstanceInfoText(instance)
-  if target_node is None:
-    pnode = instance.primary_node
-    all_nodes = instance.all_nodes
-  else:
-    pnode = target_node
-    all_nodes = [pnode]
-
-  if instance.disk_template in constants.DTS_FILEBASED:
-    file_storage_dir = os.path.dirname(instance.disks[0].logical_id[1])
-    result = lu.rpc.call_file_storage_dir_create(pnode, file_storage_dir)
-
-    result.Raise("Failed to create directory '%s' on"
-                 " node %s" % (file_storage_dir, pnode))
-
-  disks_created = []
-  # Note: this needs to be kept in sync with adding of disks in
-  # LUInstanceSetParams
-  for idx, device in enumerate(instance.disks):
-    if to_skip and idx in to_skip:
-      continue
-    logging.info("Creating disk %s for instance '%s'", idx, instance.name)
-    #HARDCODE
-    for node in all_nodes:
-      f_create = node == pnode
-      try:
-        _CreateBlockDev(lu, node, instance, device, f_create, info, f_create)
-        disks_created.append((node, device))
-      except errors.OpExecError:
-        logging.warning("Creating disk %s for instance '%s' failed",
-                        idx, instance.name)
-      except errors.DeviceCreationError, e:
-        logging.warning("Creating disk %s for instance '%s' failed",
-                        idx, instance.name)
-        disks_created.extend(e.created_devices)
-        for (node, disk) in disks_created:
-          lu.cfg.SetDiskID(disk, node)
-          result = lu.rpc.call_blockdev_remove(node, disk)
-          if result.fail_msg:
-            logging.warning("Failed to remove newly-created disk %s on node %s:"
-                            " %s", device, node, result.fail_msg)
-        raise errors.OpExecError(e.message)
-
-
-def _CalcEta(time_taken, written, total_size):
-  """Calculates the ETA based on size written and total size.
-
-  @param time_taken: The time taken so far
-  @param written: amount written so far
-  @param total_size: The total size of data to be written
-  @return: The remaining time in seconds
-
-  """
-  avg_time = time_taken / float(written)
-  return (total_size - written) * avg_time
-
-
-def _WipeDisks(lu, instance, disks=None):
-  """Wipes instance disks.
-
-  @type lu: L{LogicalUnit}
-  @param lu: the logical unit on whose behalf we execute
-  @type instance: L{objects.Instance}
-  @param instance: the instance whose disks we should create
-  @type disks: None or list of tuple of (number, L{objects.Disk}, number)
-  @param disks: Disk details; tuple contains disk index, disk object and the
-    start offset
-
-  """
-  node = instance.primary_node
-
-  if disks is None:
-    disks = [(idx, disk, 0)
-             for (idx, disk) in enumerate(instance.disks)]
-
-  for (_, device, _) in disks:
-    lu.cfg.SetDiskID(device, node)
-
-  logging.info("Pausing synchronization of disks of instance '%s'",
-               instance.name)
-  result = lu.rpc.call_blockdev_pause_resume_sync(node,
-                                                  (map(compat.snd, disks),
-                                                   instance),
-                                                  True)
-  result.Raise("Failed to pause disk synchronization on node '%s'" % node)
-
-  for idx, success in enumerate(result.payload):
-    if not success:
-      logging.warn("Pausing synchronization of disk %s of instance '%s'"
-                   " failed", idx, instance.name)
-
-  try:
-    for (idx, device, offset) in disks:
-      # The wipe size is MIN_WIPE_CHUNK_PERCENT % of the instance disk but
-      # MAX_WIPE_CHUNK at max. Truncating to integer to avoid rounding errors.
-      wipe_chunk_size = \
-        int(min(constants.MAX_WIPE_CHUNK,
-                device.size / 100.0 * constants.MIN_WIPE_CHUNK_PERCENT))
-
-      size = device.size
-      last_output = 0
-      start_time = time.time()
-
-      if offset == 0:
-        info_text = ""
-      else:
-        info_text = (" (from %s to %s)" %
-                     (utils.FormatUnit(offset, "h"),
-                      utils.FormatUnit(size, "h")))
-
-      lu.LogInfo("* Wiping disk %s%s", idx, info_text)
-
-      logging.info("Wiping disk %d for instance %s on node %s using"
-                   " chunk size %s", idx, instance.name, node, wipe_chunk_size)
-
-      while offset < size:
-        wipe_size = min(wipe_chunk_size, size - offset)
-
-        logging.debug("Wiping disk %d, offset %s, chunk %s",
-                      idx, offset, wipe_size)
-
-        result = lu.rpc.call_blockdev_wipe(node, (device, instance), offset,
-                                           wipe_size)
-        result.Raise("Could not wipe disk %d at offset %d for size %d" %
-                     (idx, offset, wipe_size))
-
-        now = time.time()
-        offset += wipe_size
-        if now - last_output >= 60:
-          eta = _CalcEta(now - start_time, offset, size)
-          lu.LogInfo(" - done: %.1f%% ETA: %s",
-                     offset / float(size) * 100, utils.FormatSeconds(eta))
-          last_output = now
-  finally:
-    logging.info("Resuming synchronization of disks for instance '%s'",
-                 instance.name)
-
-    result = lu.rpc.call_blockdev_pause_resume_sync(node,
-                                                    (map(compat.snd, disks),
-                                                     instance),
-                                                    False)
-
-    if result.fail_msg:
-      lu.LogWarning("Failed to resume disk synchronization on node '%s': %s",
-                    node, result.fail_msg)
-    else:
-      for idx, success in enumerate(result.payload):
-        if not success:
-          lu.LogWarning("Resuming synchronization of disk %s of instance '%s'"
-                        " failed", idx, instance.name)
-
-
 class LUInstanceCreate(LogicalUnit):
   """Create an instance.
 
@@ -1265,13 +404,19 @@ class LUInstanceCreate(LogicalUnit):
       raise errors.OpPrereqError("Invalid file driver name '%s'" %
                                  self.op.file_driver, errors.ECODE_INVAL)
 
+    # set default file_driver if unset and required
+    if (not self.op.file_driver and
+        self.op.disk_template in [constants.DT_FILE,
+                                  constants.DT_SHARED_FILE]):
+      self.op.file_driver = constants.FD_DEFAULT
+
     if self.op.disk_template == constants.DT_FILE:
       opcodes.RequireFileStorage()
     elif self.op.disk_template == constants.DT_SHARED_FILE:
       opcodes.RequireSharedFileStorage()
 
     ### Node/iallocator related checks
-    _CheckIAllocatorOrNode(self, "iallocator", "pnode")
+    CheckIAllocatorOrNode(self, "iallocator", "pnode")
 
     if self.op.pnode is not None:
       if self.op.disk_template in constants.DTS_INT_MIRROR:
@@ -1285,7 +430,7 @@ class LUInstanceCreate(LogicalUnit):
 
     _CheckOpportunisticLocking(self.op)
 
-    self._cds = _GetClusterDomainSecret()
+    self._cds = GetClusterDomainSecret()
 
     if self.op.mode == constants.INSTANCE_IMPORT:
       # On import force_variant must be True, because if we forced it at
@@ -1379,12 +524,11 @@ class LUInstanceCreate(LogicalUnit):
 
       if self.op.opportunistic_locking:
         self.opportunistic_locks[locking.LEVEL_NODE] = True
-        self.opportunistic_locks[locking.LEVEL_NODE_RES] = True
     else:
-      self.op.pnode = _ExpandNodeName(self.cfg, self.op.pnode)
+      self.op.pnode = ExpandNodeName(self.cfg, self.op.pnode)
       nodelist = [self.op.pnode]
       if self.op.snode is not None:
-        self.op.snode = _ExpandNodeName(self.cfg, self.op.snode)
+        self.op.snode = ExpandNodeName(self.cfg, self.op.snode)
         nodelist.append(self.op.snode)
       self.needed_locks[locking.LEVEL_NODE] = nodelist
 
@@ -1405,7 +549,7 @@ class LUInstanceCreate(LogicalUnit):
                                      " requires a source node option",
                                      errors.ECODE_INVAL)
       else:
-        self.op.src_node = src_node = _ExpandNodeName(self.cfg, src_node)
+        self.op.src_node = src_node = ExpandNodeName(self.cfg, src_node)
         if self.needed_locks[locking.LEVEL_NODE] is not locking.ALL_SET:
           self.needed_locks[locking.LEVEL_NODE].append(src_node)
         if not os.path.isabs(src_path):
@@ -1413,7 +557,15 @@ class LUInstanceCreate(LogicalUnit):
             utils.PathJoin(pathutils.EXPORT_DIR, src_path)
 
     self.needed_locks[locking.LEVEL_NODE_RES] = \
-      _CopyLockList(self.needed_locks[locking.LEVEL_NODE])
+      CopyLockList(self.needed_locks[locking.LEVEL_NODE])
+
+  def DeclareLocks(self, level):
+    if level == locking.LEVEL_NODE_RES and \
+      self.opportunistic_locks[locking.LEVEL_NODE]:
+      # Even when using opportunistic locking, we require the same set of
+      # NODE_RES locks as we got NODE locks
+      self.needed_locks[locking.LEVEL_NODE_RES] = \
+        self.owned_locks(locking.LEVEL_NODE)
 
   def _RunAllocator(self):
     """Run the allocator based on input opcode.
@@ -1470,7 +622,7 @@ class LUInstanceCreate(LogicalUnit):
       env["SRC_PATH"] = self.op.src_path
       env["SRC_IMAGES"] = self.src_images
 
-    env.update(_BuildInstanceHookEnv(
+    env.update(BuildInstanceHookEnv(
       name=self.op.instance_name,
       primary_node=self.op.pnode,
       secondary_nodes=self.secondaries,
@@ -1479,10 +631,11 @@ class LUInstanceCreate(LogicalUnit):
       minmem=self.be_full[constants.BE_MINMEM],
       maxmem=self.be_full[constants.BE_MAXMEM],
       vcpus=self.be_full[constants.BE_VCPUS],
-      nics=_NICListToTuple(self, self.nics),
+      nics=NICListToTuple(self, self.nics),
       disk_template=self.op.disk_template,
-      disks=[(d[constants.IDISK_NAME], d[constants.IDISK_SIZE],
-              d[constants.IDISK_MODE]) for d in self.disks],
+      disks=[(d[constants.IDISK_NAME], d.get("uuid", ""),
+              d[constants.IDISK_SIZE], d[constants.IDISK_MODE])
+             for d in self.disks],
       bep=self.be_full,
       hvp=self.hv_full,
       hypervisor_name=self.op.hypervisor,
@@ -1529,7 +682,7 @@ class LUInstanceCreate(LogicalUnit):
         raise errors.OpPrereqError("No export found for relative path %s" %
                                    src_path, errors.ECODE_INVAL)
 
-    _CheckNodeOnline(self, src_node)
+    CheckNodeOnline(self, src_node)
     result = self.rpc.call_export_info(src_node, src_path)
     result.Raise("No export or invalid export found in dir %s" % src_path)
 
@@ -1731,8 +884,8 @@ class LUInstanceCreate(LogicalUnit):
     hv_type.CheckParameterSyntax(filled_hvp)
     self.hv_full = filled_hvp
     # check that we don't specify global parameters on an instance
-    _CheckParamsNotGlobal(self.op.hvparams, constants.HVC_GLOBALS, "hypervisor",
-                          "instance", "cluster")
+    CheckParamsNotGlobal(self.op.hvparams, constants.HVC_GLOBALS, "hypervisor",
+                         "instance", "cluster")
 
     # fill and remember the beparams dict
     self.be_full = _ComputeFullBeParams(self.op, cluster)
@@ -1751,7 +904,7 @@ class LUInstanceCreate(LogicalUnit):
 
     # disk checks/pre-build
     default_vg = self.cfg.GetVGName()
-    self.disks = _ComputeDisks(self.op, default_vg)
+    self.disks = ComputeDisks(self.op, default_vg)
 
     if self.op.mode == constants.INSTANCE_IMPORT:
       disk_images = []
@@ -1801,9 +954,9 @@ class LUInstanceCreate(LogicalUnit):
 
     # Release all unneeded node locks
     keep_locks = filter(None, [self.op.pnode, self.op.snode, self.op.src_node])
-    _ReleaseLocks(self, locking.LEVEL_NODE, keep=keep_locks)
-    _ReleaseLocks(self, locking.LEVEL_NODE_RES, keep=keep_locks)
-    _ReleaseLocks(self, locking.LEVEL_NODE_ALLOC)
+    ReleaseLocks(self, locking.LEVEL_NODE, keep=keep_locks)
+    ReleaseLocks(self, locking.LEVEL_NODE_RES, keep=keep_locks)
+    ReleaseLocks(self, locking.LEVEL_NODE_ALLOC)
 
     assert (self.owned_locks(locking.LEVEL_NODE) ==
             self.owned_locks(locking.LEVEL_NODE_RES)), \
@@ -1870,9 +1023,9 @@ class LUInstanceCreate(LogicalUnit):
       if self.op.snode == pnode.name:
         raise errors.OpPrereqError("The secondary node cannot be the"
                                    " primary node", errors.ECODE_INVAL)
-      _CheckNodeOnline(self, self.op.snode)
-      _CheckNodeNotDrained(self, self.op.snode)
-      _CheckNodeVmCapable(self, self.op.snode)
+      CheckNodeOnline(self, self.op.snode)
+      CheckNodeNotDrained(self, self.op.snode)
+      CheckNodeVmCapable(self, self.op.snode)
       self.secondaries.append(self.op.snode)
 
       snode = self.cfg.GetNodeInfo(self.op.snode)
@@ -1886,7 +1039,7 @@ class LUInstanceCreate(LogicalUnit):
       nodes = [pnode]
       if self.op.disk_template in constants.DTS_INT_MIRROR:
         nodes.append(snode)
-      has_es = lambda n: _IsExclusiveStorageEnabledNode(self.cfg, n)
+      has_es = lambda n: IsExclusiveStorageEnabledNode(self.cfg, n)
       if compat.any(map(has_es, nodes)):
         raise errors.OpPrereqError("Disk template %s not supported with"
                                    " exclusive storage" % self.op.disk_template,
@@ -1899,14 +1052,14 @@ class LUInstanceCreate(LogicalUnit):
         # _CheckRADOSFreeSpace() is just a placeholder.
         # Any function that checks prerequisites can be placed here.
         # Check if there is enough space on the RADOS cluster.
-        _CheckRADOSFreeSpace()
+        CheckRADOSFreeSpace()
       elif self.op.disk_template == constants.DT_EXT:
         # FIXME: Function that checks prereqs if needed
         pass
       else:
         # Check lv size requirements, if not adopting
-        req_sizes = _ComputeDiskSizePerVG(self.op.disk_template, self.disks)
-        _CheckNodesFreeDiskPerVG(self, nodenames, req_sizes)
+        req_sizes = ComputeDiskSizePerVG(self.op.disk_template, self.disks)
+        CheckNodesFreeDiskPerVG(self, nodenames, req_sizes)
 
     elif self.op.disk_template == constants.DT_PLAIN: # Check the adoption data
       all_lvs = set(["%s/%s" % (disk[constants.IDISK_VG],
@@ -1999,13 +1152,13 @@ class LUInstanceCreate(LogicalUnit):
              (pnode.group, group_info.name, utils.CommaJoin(res)))
       raise errors.OpPrereqError(msg, errors.ECODE_INVAL)
 
-    _CheckHVParams(self, nodenames, self.op.hypervisor, self.op.hvparams)
+    CheckHVParams(self, nodenames, self.op.hypervisor, self.op.hvparams)
 
-    _CheckNodeHasOS(self, pnode.name, self.op.os_type, self.op.force_variant)
+    CheckNodeHasOS(self, pnode.name, self.op.os_type, self.op.force_variant)
     # check OS parameters (remotely)
-    _CheckOSParams(self, True, nodenames, self.op.os_type, self.os_full)
+    CheckOSParams(self, True, nodenames, self.op.os_type, self.os_full)
 
-    _CheckNicsBridgesExist(self, self.nics, self.pnode.name)
+    CheckNicsBridgesExist(self, self.nics, self.pnode.name)
 
     #TODO: _CheckExtParams (remotely)
     # Check parameters for extstorage
@@ -2013,10 +1166,10 @@ class LUInstanceCreate(LogicalUnit):
     # memory check on primary node
     #TODO(dynmem): use MINMEM for checking
     if self.op.start:
-      _CheckNodeFreeMemory(self, self.pnode.name,
-                           "creating instance %s" % self.op.instance_name,
-                           self.be_full[constants.BE_MAXMEM],
-                           self.op.hypervisor)
+      CheckNodeFreeMemory(self, self.pnode.name,
+                          "creating instance %s" % self.op.instance_name,
+                          self.be_full[constants.BE_MAXMEM],
+                          self.op.hypervisor)
 
     self.dry_run_result = list(nodenames)
 
@@ -2043,21 +1196,22 @@ class LUInstanceCreate(LogicalUnit):
     # has no disks yet (we are generating them right here).
     node = self.cfg.GetNodeInfo(pnode_name)
     nodegroup = self.cfg.GetNodeGroup(node.group)
-    disks = _GenerateDiskTemplate(self,
-                                  self.op.disk_template,
-                                  instance, pnode_name,
-                                  self.secondaries,
-                                  self.disks,
-                                  self.instance_file_storage_dir,
-                                  self.op.file_driver,
-                                  0,
-                                  feedback_fn,
-                                  self.cfg.GetGroupDiskParams(nodegroup))
+    disks = GenerateDiskTemplate(self,
+                                 self.op.disk_template,
+                                 instance, pnode_name,
+                                 self.secondaries,
+                                 self.disks,
+                                 self.instance_file_storage_dir,
+                                 self.op.file_driver,
+                                 0,
+                                 feedback_fn,
+                                 self.cfg.GetGroupDiskParams(nodegroup))
 
     iobj = objects.Instance(name=instance, os=self.op.os_type,
                             primary_node=pnode_name,
                             nics=self.nics, disks=disks,
                             disk_template=self.op.disk_template,
+                            disks_active=False,
                             admin_state=constants.ADMINST_DOWN,
                             network_port=network_port,
                             beparams=self.op.beparams,
@@ -2086,7 +1240,7 @@ class LUInstanceCreate(LogicalUnit):
     else:
       feedback_fn("* creating instance disks...")
       try:
-        _CreateDisks(self, iobj)
+        CreateDisks(self, iobj)
       except errors.OpExecError:
         self.LogWarning("Device creation failed")
         self.cfg.ReleaseDRBDMinors(instance)
@@ -2102,16 +1256,16 @@ class LUInstanceCreate(LogicalUnit):
 
     if self.op.mode == constants.INSTANCE_IMPORT:
       # Release unused nodes
-      _ReleaseLocks(self, locking.LEVEL_NODE, keep=[self.op.src_node])
+      ReleaseLocks(self, locking.LEVEL_NODE, keep=[self.op.src_node])
     else:
       # Release all nodes
-      _ReleaseLocks(self, locking.LEVEL_NODE)
+      ReleaseLocks(self, locking.LEVEL_NODE)
 
     disk_abort = False
     if not self.adopt_disks and self.cfg.GetClusterInfo().prealloc_wipe_disks:
       feedback_fn("* wiping instance disks...")
       try:
-        _WipeDisks(self, iobj)
+        WipeDisks(self, iobj)
       except errors.OpExecError, err:
         logging.exception("Wiping disks failed")
         self.LogWarning("Wiping instance disks failed (%s)", err)
@@ -2121,24 +1275,27 @@ class LUInstanceCreate(LogicalUnit):
       # Something is already wrong with the disks, don't do anything else
       pass
     elif self.op.wait_for_sync:
-      disk_abort = not _WaitForSync(self, iobj)
+      disk_abort = not WaitForSync(self, iobj)
     elif iobj.disk_template in constants.DTS_INT_MIRROR:
       # make sure the disks are not degraded (still sync-ing is ok)
       feedback_fn("* checking mirrors status")
-      disk_abort = not _WaitForSync(self, iobj, oneshot=True)
+      disk_abort = not WaitForSync(self, iobj, oneshot=True)
     else:
       disk_abort = False
 
     if disk_abort:
-      _RemoveDisks(self, iobj)
+      RemoveDisks(self, iobj)
       self.cfg.RemoveInstance(iobj.name)
       # Make sure the instance lock gets removed
       self.remove_locks[locking.LEVEL_INSTANCE] = iobj.name
       raise errors.OpExecError("There are some degraded disks for"
                                " this instance")
 
+    # instance disks are now active
+    iobj.disks_active = True
+
     # Release all node resource locks
-    _ReleaseLocks(self, locking.LEVEL_NODE_RES)
+    ReleaseLocks(self, locking.LEVEL_NODE_RES)
 
     if iobj.disk_template != constants.DT_DISKLESS and not self.adopt_disks:
       # we need to set the disks ID to the primary node, since the
@@ -2259,13 +1416,6 @@ class LUInstanceCreate(LogicalUnit):
     return list(iobj.all_nodes)
 
 
-def _GetInstanceInfoText(instance):
-  """Compute that text that should be added to the disk's metadata.
-
-  """
-  return "originstname+%s" % instance.name
-
-
 class LUInstanceRename(LogicalUnit):
   """Rename an instance.
 
@@ -2288,7 +1438,7 @@ class LUInstanceRename(LogicalUnit):
     This runs on master, primary and secondary nodes of the instance.
 
     """
-    env = _BuildInstanceHookEnvByObject(self, self.instance)
+    env = BuildInstanceHookEnvByObject(self, self.instance)
     env["INSTANCE_NEW_NAME"] = self.op.new_name
     return env
 
@@ -2305,13 +1455,13 @@ class LUInstanceRename(LogicalUnit):
     This checks that the instance is in the cluster and is not running.
 
     """
-    self.op.instance_name = _ExpandInstanceName(self.cfg,
-                                                self.op.instance_name)
+    self.op.instance_name = ExpandInstanceName(self.cfg,
+                                               self.op.instance_name)
     instance = self.cfg.GetInstanceInfo(self.op.instance_name)
     assert instance is not None
-    _CheckNodeOnline(self, instance.primary_node)
-    _CheckInstanceState(self, instance, INSTANCE_NOT_RUNNING,
-                        msg="cannot rename")
+    CheckNodeOnline(self, instance.primary_node)
+    CheckInstanceState(self, instance, INSTANCE_NOT_RUNNING,
+                       msg="cannot rename")
     self.instance = instance
 
     new_name = self.op.new_name
@@ -2363,9 +1513,9 @@ class LUInstanceRename(LogicalUnit):
                    (inst.primary_node, old_file_storage_dir,
                     new_file_storage_dir))
 
-    _StartInstanceDisks(self, inst, None)
+    StartInstanceDisks(self, inst, None)
     # update info on disks
-    info = _GetInstanceInfoText(inst)
+    info = GetInstanceInfoText(inst)
     for (idx, disk) in enumerate(inst.disks):
       for node in inst.all_nodes:
         self.cfg.SetDiskID(disk, node)
@@ -2383,7 +1533,7 @@ class LUInstanceRename(LogicalUnit):
                (inst.name, inst.primary_node, msg))
         self.LogWarning(msg)
     finally:
-      _ShutdownInstanceDisks(self, inst)
+      ShutdownInstanceDisks(self, inst)
 
     return inst.name
 
@@ -2408,7 +1558,7 @@ class LUInstanceRemove(LogicalUnit):
     elif level == locking.LEVEL_NODE_RES:
       # Copy node locks
       self.needed_locks[locking.LEVEL_NODE_RES] = \
-        _CopyLockList(self.needed_locks[locking.LEVEL_NODE])
+        CopyLockList(self.needed_locks[locking.LEVEL_NODE])
 
   def BuildHooksEnv(self):
     """Build hooks env.
@@ -2416,7 +1566,7 @@ class LUInstanceRemove(LogicalUnit):
     This runs on master, primary and secondary nodes of the instance.
 
     """
-    env = _BuildInstanceHookEnvByObject(self, self.instance)
+    env = BuildInstanceHookEnvByObject(self, self.instance)
     env["SHUTDOWN_TIMEOUT"] = self.op.shutdown_timeout
     return env
 
@@ -2464,63 +1614,7 @@ class LUInstanceRemove(LogicalUnit):
                 self.owned_locks(locking.LEVEL_NODE)), \
       "Not owning correct locks"
 
-    _RemoveInstance(self, feedback_fn, instance, self.op.ignore_failures)
-
-
-def _CheckInstanceBridgesExist(lu, instance, node=None):
-  """Check that the brigdes needed by an instance exist.
-
-  """
-  if node is None:
-    node = instance.primary_node
-  _CheckNicsBridgesExist(lu, instance.nics, node)
-
-
-def _ComputeIPolicyNodeViolation(ipolicy, instance, current_group,
-                                 target_group, cfg,
-                                 _compute_fn=_ComputeIPolicyInstanceViolation):
-  """Compute if instance meets the specs of the new target group.
-
-  @param ipolicy: The ipolicy to verify
-  @param instance: The instance object to verify
-  @param current_group: The current group of the instance
-  @param target_group: The new group of the instance
-  @type cfg: L{config.ConfigWriter}
-  @param cfg: Cluster configuration
-  @param _compute_fn: The function to verify ipolicy (unittest only)
-  @see: L{_ComputeIPolicySpecViolation}
-
-  """
-  if current_group == target_group:
-    return []
-  else:
-    return _compute_fn(ipolicy, instance, cfg)
-
-
-def _CheckTargetNodeIPolicy(lu, ipolicy, instance, node, cfg, ignore=False,
-                            _compute_fn=_ComputeIPolicyNodeViolation):
-  """Checks that the target node is correct in terms of instance policy.
-
-  @param ipolicy: The ipolicy to verify
-  @param instance: The instance object to verify
-  @param node: The new node to relocate
-  @type cfg: L{config.ConfigWriter}
-  @param cfg: Cluster configuration
-  @param ignore: Ignore violations of the ipolicy
-  @param _compute_fn: The function to verify ipolicy (unittest only)
-  @see: L{_ComputeIPolicySpecViolation}
-
-  """
-  primary_node = lu.cfg.GetNodeInfo(instance.primary_node)
-  res = _compute_fn(ipolicy, instance, primary_node.group, node.group, cfg)
-
-  if res:
-    msg = ("Instance does not meet target node group's (%s) instance"
-           " policy: %s") % (node.group, utils.CommaJoin(res))
-    if ignore:
-      lu.LogWarning(msg)
-    else:
-      raise errors.OpPrereqError(msg, errors.ECODE_INVAL)
+    RemoveInstance(self, feedback_fn, instance, self.op.ignore_failures)
 
 
 class LUInstanceMove(LogicalUnit):
@@ -2533,7 +1627,7 @@ class LUInstanceMove(LogicalUnit):
 
   def ExpandNames(self):
     self._ExpandAndLockInstance()
-    target_node = _ExpandNodeName(self.cfg, self.op.target_node)
+    target_node = ExpandNodeName(self.cfg, self.op.target_node)
     self.op.target_node = target_node
     self.needed_locks[locking.LEVEL_NODE] = [target_node]
     self.needed_locks[locking.LEVEL_NODE_RES] = []
@@ -2545,7 +1639,7 @@ class LUInstanceMove(LogicalUnit):
     elif level == locking.LEVEL_NODE_RES:
       # Copy node locks
       self.needed_locks[locking.LEVEL_NODE_RES] = \
-        _CopyLockList(self.needed_locks[locking.LEVEL_NODE])
+        CopyLockList(self.needed_locks[locking.LEVEL_NODE])
 
   def BuildHooksEnv(self):
     """Build hooks env.
@@ -2557,7 +1651,7 @@ class LUInstanceMove(LogicalUnit):
       "TARGET_NODE": self.op.target_node,
       "SHUTDOWN_TIMEOUT": self.op.shutdown_timeout,
       }
-    env.update(_BuildInstanceHookEnvByObject(self, self.instance))
+    env.update(BuildInstanceHookEnvByObject(self, self.instance))
     return env
 
   def BuildHooksNodes(self):
@@ -2603,27 +1697,27 @@ class LUInstanceMove(LogicalUnit):
         raise errors.OpPrereqError("Instance disk %d has a complex layout,"
                                    " cannot copy" % idx, errors.ECODE_STATE)
 
-    _CheckNodeOnline(self, target_node)
-    _CheckNodeNotDrained(self, target_node)
-    _CheckNodeVmCapable(self, target_node)
+    CheckNodeOnline(self, target_node)
+    CheckNodeNotDrained(self, target_node)
+    CheckNodeVmCapable(self, target_node)
     cluster = self.cfg.GetClusterInfo()
     group_info = self.cfg.GetNodeGroup(node.group)
     ipolicy = ganeti.masterd.instance.CalculateGroupIPolicy(cluster, group_info)
-    _CheckTargetNodeIPolicy(self, ipolicy, instance, node, self.cfg,
-                            ignore=self.op.ignore_ipolicy)
+    CheckTargetNodeIPolicy(self, ipolicy, instance, node, self.cfg,
+                           ignore=self.op.ignore_ipolicy)
 
     if instance.admin_state == constants.ADMINST_UP:
       # check memory requirements on the secondary node
-      _CheckNodeFreeMemory(self, target_node,
-                           "failing over instance %s" %
-                           instance.name, bep[constants.BE_MAXMEM],
-                           instance.hypervisor)
+      CheckNodeFreeMemory(self, target_node,
+                          "failing over instance %s" %
+                          instance.name, bep[constants.BE_MAXMEM],
+                          instance.hypervisor)
     else:
       self.LogInfo("Not checking memory on the secondary node as"
                    " instance will not be started")
 
     # check bridge existance
-    _CheckInstanceBridgesExist(self, instance, node=target_node)
+    CheckInstanceBridgesExist(self, instance, node=target_node)
 
   def Exec(self, feedback_fn):
     """Move an instance.
@@ -2660,7 +1754,7 @@ class LUInstanceMove(LogicalUnit):
 
     # create the target disks
     try:
-      _CreateDisks(self, instance, target_node=target_node)
+      CreateDisks(self, instance, target_node=target_node)
     except errors.OpExecError:
       self.LogWarning("Device creation failed")
       self.cfg.ReleaseDRBDMinors(instance.name)
@@ -2692,7 +1786,7 @@ class LUInstanceMove(LogicalUnit):
     if errs:
       self.LogWarning("Some disks failed to copy, aborting")
       try:
-        _RemoveDisks(self, instance, target_node=target_node)
+        RemoveDisks(self, instance, target_node=target_node)
       finally:
         self.cfg.ReleaseDRBDMinors(instance.name)
         raise errors.OpExecError("Errors during disk copy: %s" %
@@ -2702,17 +1796,17 @@ class LUInstanceMove(LogicalUnit):
     self.cfg.Update(instance, feedback_fn)
 
     self.LogInfo("Removing the disks on the original node")
-    _RemoveDisks(self, instance, target_node=source_node)
+    RemoveDisks(self, instance, target_node=source_node)
 
     # Only start the instance if it's marked as up
     if instance.admin_state == constants.ADMINST_UP:
       self.LogInfo("Starting instance %s on node %s",
                    instance.name, target_node)
 
-      disks_ok, _ = _AssembleInstanceDisks(self, instance,
-                                           ignore_secondaries=True)
+      disks_ok, _ = AssembleInstanceDisks(self, instance,
+                                          ignore_secondaries=True)
       if not disks_ok:
-        _ShutdownInstanceDisks(self, instance)
+        ShutdownInstanceDisks(self, instance)
         raise errors.OpExecError("Can't activate the instance's disks")
 
       result = self.rpc.call_instance_start(target_node,
@@ -2720,793 +1814,621 @@ class LUInstanceMove(LogicalUnit):
                                             self.op.reason)
       msg = result.fail_msg
       if msg:
-        _ShutdownInstanceDisks(self, instance)
+        ShutdownInstanceDisks(self, instance)
         raise errors.OpExecError("Could not start instance %s on node %s: %s" %
                                  (instance.name, target_node, msg))
 
 
-def _GetInstanceConsole(cluster, instance):
-  """Returns console information for an instance.
-
-  @type cluster: L{objects.Cluster}
-  @type instance: L{objects.Instance}
-  @rtype: dict
+class LUInstanceMultiAlloc(NoHooksLU):
+  """Allocates multiple instances at the same time.
 
   """
-  hyper = hypervisor.GetHypervisorClass(instance.hypervisor)
-  # beparams and hvparams are passed separately, to avoid editing the
-  # instance and then saving the defaults in the instance itself.
-  hvparams = cluster.FillHV(instance)
-  beparams = cluster.FillBE(instance)
-  console = hyper.GetInstanceConsole(instance, hvparams, beparams)
-
-  assert console.instance == instance.name
-  assert console.Validate()
-
-  return console.ToDict()
+  REQ_BGL = False
 
+  def CheckArguments(self):
+    """Check arguments.
 
-class _InstanceQuery(_QueryBase):
-  FIELDS = query.INSTANCE_FIELDS
+    """
+    nodes = []
+    for inst in self.op.instances:
+      if inst.iallocator is not None:
+        raise errors.OpPrereqError("iallocator are not allowed to be set on"
+                                   " instance objects", errors.ECODE_INVAL)
+      nodes.append(bool(inst.pnode))
+      if inst.disk_template in constants.DTS_INT_MIRROR:
+        nodes.append(bool(inst.snode))
 
-  def ExpandNames(self, lu):
-    lu.needed_locks = {}
-    lu.share_locks = _ShareAll()
+    has_nodes = compat.any(nodes)
+    if compat.all(nodes) ^ has_nodes:
+      raise errors.OpPrereqError("There are instance objects providing"
+                                 " pnode/snode while others do not",
+                                 errors.ECODE_INVAL)
 
-    if self.names:
-      self.wanted = _GetWantedInstances(lu, self.names)
-    else:
-      self.wanted = locking.ALL_SET
-
-    self.do_locking = (self.use_locking and
-                       query.IQ_LIVE in self.requested_data)
-    if self.do_locking:
-      lu.needed_locks[locking.LEVEL_INSTANCE] = self.wanted
-      lu.needed_locks[locking.LEVEL_NODEGROUP] = []
-      lu.needed_locks[locking.LEVEL_NODE] = []
-      lu.needed_locks[locking.LEVEL_NETWORK] = []
-      lu.recalculate_locks[locking.LEVEL_NODE] = constants.LOCKS_REPLACE
-
-    self.do_grouplocks = (self.do_locking and
-                          query.IQ_NODES in self.requested_data)
-
-  def DeclareLocks(self, lu, level):
-    if self.do_locking:
-      if level == locking.LEVEL_NODEGROUP and self.do_grouplocks:
-        assert not lu.needed_locks[locking.LEVEL_NODEGROUP]
-
-        # Lock all groups used by instances optimistically; this requires going
-        # via the node before it's locked, requiring verification later on
-        lu.needed_locks[locking.LEVEL_NODEGROUP] = \
-          set(group_uuid
-              for instance_name in lu.owned_locks(locking.LEVEL_INSTANCE)
-              for group_uuid in lu.cfg.GetInstanceNodeGroups(instance_name))
-      elif level == locking.LEVEL_NODE:
-        lu._LockInstancesNodes() # pylint: disable=W0212
-
-      elif level == locking.LEVEL_NETWORK:
-        lu.needed_locks[locking.LEVEL_NETWORK] = \
-          frozenset(net_uuid
-                    for instance_name in lu.owned_locks(locking.LEVEL_INSTANCE)
-                    for net_uuid in lu.cfg.GetInstanceNetworks(instance_name))
+    if not has_nodes and self.op.iallocator is None:
+      default_iallocator = self.cfg.GetDefaultIAllocator()
+      if default_iallocator:
+        self.op.iallocator = default_iallocator
+      else:
+        raise errors.OpPrereqError("No iallocator or nodes on the instances"
+                                   " given and no cluster-wide default"
+                                   " iallocator found; please specify either"
+                                   " an iallocator or nodes on the instances"
+                                   " or set a cluster-wide default iallocator",
+                                   errors.ECODE_INVAL)
 
-  @staticmethod
-  def _CheckGroupLocks(lu):
-    owned_instances = frozenset(lu.owned_locks(locking.LEVEL_INSTANCE))
-    owned_groups = frozenset(lu.owned_locks(locking.LEVEL_NODEGROUP))
+    _CheckOpportunisticLocking(self.op)
 
-    # Check if node groups for locked instances are still correct
-    for instance_name in owned_instances:
-      _CheckInstanceNodeGroups(lu.cfg, instance_name, owned_groups)
+    dups = utils.FindDuplicates([op.instance_name for op in self.op.instances])
+    if dups:
+      raise errors.OpPrereqError("There are duplicate instance names: %s" %
+                                 utils.CommaJoin(dups), errors.ECODE_INVAL)
 
-  def _GetQueryData(self, lu):
-    """Computes the list of instances and their attributes.
+  def ExpandNames(self):
+    """Calculate the locks.
 
     """
-    if self.do_grouplocks:
-      self._CheckGroupLocks(lu)
-
-    cluster = lu.cfg.GetClusterInfo()
-    all_info = lu.cfg.GetAllInstancesInfo()
-
-    instance_names = self._GetNames(lu, all_info.keys(), locking.LEVEL_INSTANCE)
-
-    instance_list = [all_info[name] for name in instance_names]
-    nodes = frozenset(itertools.chain(*(inst.all_nodes
-                                        for inst in instance_list)))
-    hv_list = list(set([inst.hypervisor for inst in instance_list]))
-    bad_nodes = []
-    offline_nodes = []
-    wrongnode_inst = set()
-
-    # Gather data as requested
-    if self.requested_data & set([query.IQ_LIVE, query.IQ_CONSOLE]):
-      live_data = {}
-      node_data = lu.rpc.call_all_instances_info(nodes, hv_list)
-      for name in nodes:
-        result = node_data[name]
-        if result.offline:
-          # offline nodes will be in both lists
-          assert result.fail_msg
-          offline_nodes.append(name)
-        if result.fail_msg:
-          bad_nodes.append(name)
-        elif result.payload:
-          for inst in result.payload:
-            if inst in all_info:
-              if all_info[inst].primary_node == name:
-                live_data.update(result.payload)
-              else:
-                wrongnode_inst.add(inst)
-            else:
-              # orphan instance; we don't list it here as we don't
-              # handle this case yet in the output of instance listing
-              logging.warning("Orphan instance '%s' found on node %s",
-                              inst, name)
-              # else no instance is alive
-    else:
-      live_data = {}
-
-    if query.IQ_DISKUSAGE in self.requested_data:
-      gmi = ganeti.masterd.instance
-      disk_usage = dict((inst.name,
-                         gmi.ComputeDiskSize(inst.disk_template,
-                                             [{constants.IDISK_SIZE: disk.size}
-                                              for disk in inst.disks]))
-                        for inst in instance_list)
-    else:
-      disk_usage = None
-
-    if query.IQ_CONSOLE in self.requested_data:
-      consinfo = {}
-      for inst in instance_list:
-        if inst.name in live_data:
-          # Instance is running
-          consinfo[inst.name] = _GetInstanceConsole(cluster, inst)
-        else:
-          consinfo[inst.name] = None
-      assert set(consinfo.keys()) == set(instance_names)
-    else:
-      consinfo = None
-
-    if query.IQ_NODES in self.requested_data:
-      node_names = set(itertools.chain(*map(operator.attrgetter("all_nodes"),
-                                            instance_list)))
-      nodes = dict(lu.cfg.GetMultiNodeInfo(node_names))
-      groups = dict((uuid, lu.cfg.GetNodeGroup(uuid))
-                    for uuid in set(map(operator.attrgetter("group"),
-                                        nodes.values())))
-    else:
-      nodes = None
-      groups = None
+    self.share_locks = ShareAll()
+    self.needed_locks = {
+      # iallocator will select nodes and even if no iallocator is used,
+      # collisions with LUInstanceCreate should be avoided
+      locking.LEVEL_NODE_ALLOC: locking.ALL_SET,
+      }
 
-    if query.IQ_NETWORKS in self.requested_data:
-      net_uuids = itertools.chain(*(lu.cfg.GetInstanceNetworks(i.name)
-                                    for i in instance_list))
-      networks = dict((uuid, lu.cfg.GetNetwork(uuid)) for uuid in net_uuids)
-    else:
-      networks = None
+    if self.op.iallocator:
+      self.needed_locks[locking.LEVEL_NODE] = locking.ALL_SET
+      self.needed_locks[locking.LEVEL_NODE_RES] = locking.ALL_SET
 
-    return query.InstanceQueryData(instance_list, lu.cfg.GetClusterInfo(),
-                                   disk_usage, offline_nodes, bad_nodes,
-                                   live_data, wrongnode_inst, consinfo,
-                                   nodes, groups, networks)
+      if self.op.opportunistic_locking:
+        self.opportunistic_locks[locking.LEVEL_NODE] = True
+    else:
+      nodeslist = []
+      for inst in self.op.instances:
+        inst.pnode = ExpandNodeName(self.cfg, inst.pnode)
+        nodeslist.append(inst.pnode)
+        if inst.snode is not None:
+          inst.snode = ExpandNodeName(self.cfg, inst.snode)
+          nodeslist.append(inst.snode)
 
+      self.needed_locks[locking.LEVEL_NODE] = nodeslist
+      # Lock resources of instance's primary and secondary nodes (copy to
+      # prevent accidential modification)
+      self.needed_locks[locking.LEVEL_NODE_RES] = list(nodeslist)
 
-class LUInstanceQuery(NoHooksLU):
-  """Logical unit for querying instances.
+  def DeclareLocks(self, level):
+    if level == locking.LEVEL_NODE_RES and \
+      self.opportunistic_locks[locking.LEVEL_NODE]:
+      # Even when using opportunistic locking, we require the same set of
+      # NODE_RES locks as we got NODE locks
+      self.needed_locks[locking.LEVEL_NODE_RES] = \
+        self.owned_locks(locking.LEVEL_NODE)
 
-  """
-  # pylint: disable=W0142
-  REQ_BGL = False
+  def CheckPrereq(self):
+    """Check prerequisite.
 
-  def CheckArguments(self):
-    self.iq = _InstanceQuery(qlang.MakeSimpleFilter("name", self.op.names),
-                             self.op.output_fields, self.op.use_locking)
+    """
+    if self.op.iallocator:
+      cluster = self.cfg.GetClusterInfo()
+      default_vg = self.cfg.GetVGName()
+      ec_id = self.proc.GetECId()
 
-  def ExpandNames(self):
-    self.iq.ExpandNames(self)
+      if self.op.opportunistic_locking:
+        # Only consider nodes for which a lock is held
+        node_whitelist = list(self.owned_locks(locking.LEVEL_NODE))
+      else:
+        node_whitelist = None
 
-  def DeclareLocks(self, level):
-    self.iq.DeclareLocks(self, level)
+      insts = [_CreateInstanceAllocRequest(op, ComputeDisks(op, default_vg),
+                                           _ComputeNics(op, cluster, None,
+                                                        self.cfg, ec_id),
+                                           _ComputeFullBeParams(op, cluster),
+                                           node_whitelist)
+               for op in self.op.instances]
 
-  def Exec(self, feedback_fn):
-    return self.iq.OldStyleQuery(self)
+      req = iallocator.IAReqMultiInstanceAlloc(instances=insts)
+      ial = iallocator.IAllocator(self.cfg, self.rpc, req)
 
+      ial.Run(self.op.iallocator)
 
-class LUInstanceQueryData(NoHooksLU):
-  """Query runtime instance data.
+      if not ial.success:
+        raise errors.OpPrereqError("Can't compute nodes using"
+                                   " iallocator '%s': %s" %
+                                   (self.op.iallocator, ial.info),
+                                   errors.ECODE_NORES)
 
-  """
-  REQ_BGL = False
+      self.ia_result = ial.result
 
-  def ExpandNames(self):
-    self.needed_locks = {}
+    if self.op.dry_run:
+      self.dry_run_result = objects.FillDict(self._ConstructPartialResult(), {
+        constants.JOB_IDS_KEY: [],
+        })
 
-    # Use locking if requested or when non-static information is wanted
-    if not (self.op.static or self.op.use_locking):
-      self.LogWarning("Non-static data requested, locks need to be acquired")
-      self.op.use_locking = True
+  def _ConstructPartialResult(self):
+    """Contructs the partial result.
 
-    if self.op.instances or not self.op.use_locking:
-      # Expand instance names right here
-      self.wanted_names = _GetWantedInstances(self, self.op.instances)
+    """
+    if self.op.iallocator:
+      (allocatable, failed_insts) = self.ia_result
+      allocatable_insts = map(compat.fst, allocatable)
     else:
-      # Will use acquired locks
-      self.wanted_names = None
-
-    if self.op.use_locking:
-      self.share_locks = _ShareAll()
+      allocatable_insts = [op.instance_name for op in self.op.instances]
+      failed_insts = []
 
-      if self.wanted_names is None:
-        self.needed_locks[locking.LEVEL_INSTANCE] = locking.ALL_SET
-      else:
-        self.needed_locks[locking.LEVEL_INSTANCE] = self.wanted_names
+    return {
+      opcodes.OpInstanceMultiAlloc.ALLOCATABLE_KEY: allocatable_insts,
+      opcodes.OpInstanceMultiAlloc.FAILED_KEY: failed_insts,
+      }
 
-      self.needed_locks[locking.LEVEL_NODEGROUP] = []
-      self.needed_locks[locking.LEVEL_NODE] = []
-      self.needed_locks[locking.LEVEL_NETWORK] = []
-      self.recalculate_locks[locking.LEVEL_NODE] = constants.LOCKS_REPLACE
+  def Exec(self, feedback_fn):
+    """Executes the opcode.
 
-  def DeclareLocks(self, level):
-    if self.op.use_locking:
-      owned_instances = self.owned_locks(locking.LEVEL_INSTANCE)
-      if level == locking.LEVEL_NODEGROUP:
+    """
+    jobs = []
+    if self.op.iallocator:
+      op2inst = dict((op.instance_name, op) for op in self.op.instances)
+      (allocatable, failed) = self.ia_result
 
-        # Lock all groups used by instances optimistically; this requires going
-        # via the node before it's locked, requiring verification later on
-        self.needed_locks[locking.LEVEL_NODEGROUP] = \
-          frozenset(group_uuid
-                    for instance_name in owned_instances
-                    for group_uuid in
-                    self.cfg.GetInstanceNodeGroups(instance_name))
+      for (name, nodes) in allocatable:
+        op = op2inst.pop(name)
 
-      elif level == locking.LEVEL_NODE:
-        self._LockInstancesNodes()
+        if len(nodes) > 1:
+          (op.pnode, op.snode) = nodes
+        else:
+          (op.pnode,) = nodes
 
-      elif level == locking.LEVEL_NETWORK:
-        self.needed_locks[locking.LEVEL_NETWORK] = \
-          frozenset(net_uuid
-                    for instance_name in owned_instances
-                    for net_uuid in
-                    self.cfg.GetInstanceNetworks(instance_name))
+        jobs.append([op])
 
-  def CheckPrereq(self):
-    """Check prerequisites.
+      missing = set(op2inst.keys()) - set(failed)
+      assert not missing, \
+        "Iallocator did return incomplete result: %s" % \
+        utils.CommaJoin(missing)
+    else:
+      jobs.extend([op] for op in self.op.instances)
 
-    This only checks the optional instance list against the existing names.
+    return ResultWithJobs(jobs, **self._ConstructPartialResult())
 
-    """
-    owned_instances = frozenset(self.owned_locks(locking.LEVEL_INSTANCE))
-    owned_groups = frozenset(self.owned_locks(locking.LEVEL_NODEGROUP))
-    owned_nodes = frozenset(self.owned_locks(locking.LEVEL_NODE))
-    owned_networks = frozenset(self.owned_locks(locking.LEVEL_NETWORK))
 
-    if self.wanted_names is None:
-      assert self.op.use_locking, "Locking was not used"
-      self.wanted_names = owned_instances
+class _InstNicModPrivate:
+  """Data structure for network interface modifications.
 
-    instances = dict(self.cfg.GetMultiInstanceInfo(self.wanted_names))
+  Used by L{LUInstanceSetParams}.
 
-    if self.op.use_locking:
-      _CheckInstancesNodeGroups(self.cfg, instances, owned_groups, owned_nodes,
-                                None)
-    else:
-      assert not (owned_instances or owned_groups or
-                  owned_nodes or owned_networks)
+  """
+  def __init__(self):
+    self.params = None
+    self.filled = None
 
-    self.wanted_instances = instances.values()
 
-  def _ComputeBlockdevStatus(self, node, instance, dev):
-    """Returns the status of a block device
+def _PrepareContainerMods(mods, private_fn):
+  """Prepares a list of container modifications by adding a private data field.
 
-    """
-    if self.op.static or not node:
-      return None
+  @type mods: list of tuples; (operation, index, parameters)
+  @param mods: List of modifications
+  @type private_fn: callable or None
+  @param private_fn: Callable for constructing a private data field for a
+    modification
+  @rtype: list
 
-    self.cfg.SetDiskID(dev, node)
+  """
+  if private_fn is None:
+    fn = lambda: None
+  else:
+    fn = private_fn
 
-    result = self.rpc.call_blockdev_find(node, dev)
-    if result.offline:
-      return None
+  return [(op, idx, params, fn()) for (op, idx, params) in mods]
 
-    result.Raise("Can't compute disk status for %s" % instance.name)
 
-    status = result.payload
-    if status is None:
-      return None
+def _CheckNodesPhysicalCPUs(lu, nodenames, requested, hypervisor_name):
+  """Checks if nodes have enough physical CPUs
 
-    return (status.dev_path, status.major, status.minor,
-            status.sync_percent, status.estimated_time,
-            status.is_degraded, status.ldisk_status)
+  This function checks if all given nodes have the needed number of
+  physical CPUs. In case any node has less CPUs or we cannot get the
+  information from the node, this function raises an OpPrereqError
+  exception.
 
-  def _ComputeDiskStatus(self, instance, snode, dev):
-    """Compute block device status.
+  @type lu: C{LogicalUnit}
+  @param lu: a logical unit from which we get configuration data
+  @type nodenames: C{list}
+  @param nodenames: the list of node names to check
+  @type requested: C{int}
+  @param requested: the minimum acceptable number of physical CPUs
+  @raise errors.OpPrereqError: if the node doesn't have enough CPUs,
+      or we cannot check the node
 
-    """
-    (anno_dev,) = _AnnotateDiskParams(instance, [dev], self.cfg)
+  """
+  nodeinfo = lu.rpc.call_node_info(nodenames, None, [hypervisor_name], None)
+  for node in nodenames:
+    info = nodeinfo[node]
+    info.Raise("Cannot get current information from node %s" % node,
+               prereq=True, ecode=errors.ECODE_ENVIRON)
+    (_, _, (hv_info, )) = info.payload
+    num_cpus = hv_info.get("cpu_total", None)
+    if not isinstance(num_cpus, int):
+      raise errors.OpPrereqError("Can't compute the number of physical CPUs"
+                                 " on node %s, result was '%s'" %
+                                 (node, num_cpus), errors.ECODE_ENVIRON)
+    if requested > num_cpus:
+      raise errors.OpPrereqError("Node %s has %s physical CPUs, but %s are "
+                                 "required" % (node, num_cpus, requested),
+                                 errors.ECODE_NORES)
 
-    return self._ComputeDiskStatusInner(instance, snode, anno_dev)
 
-  def _ComputeDiskStatusInner(self, instance, snode, dev):
-    """Compute block device status.
+def GetItemFromContainer(identifier, kind, container):
+  """Return the item refered by the identifier.
 
-    @attention: The device has to be annotated already.
+  @type identifier: string
+  @param identifier: Item index or name or UUID
+  @type kind: string
+  @param kind: One-word item description
+  @type container: list
+  @param container: Container to get the item from
 
-    """
-    if dev.dev_type in constants.LDS_DRBD:
-      # we change the snode then (otherwise we use the one passed in)
-      if dev.logical_id[0] == instance.primary_node:
-        snode = dev.logical_id[1]
-      else:
-        snode = dev.logical_id[0]
+  """
+  # Index
+  try:
+    idx = int(identifier)
+    if idx == -1:
+      # Append
+      absidx = len(container) - 1
+    elif idx < 0:
+      raise IndexError("Not accepting negative indices other than -1")
+    elif idx > len(container):
+      raise IndexError("Got %s index %s, but there are only %s" %
+                       (kind, idx, len(container)))
+    else:
+      absidx = idx
+    return (absidx, container[idx])
+  except ValueError:
+    pass
 
-    dev_pstatus = self._ComputeBlockdevStatus(instance.primary_node,
-                                              instance, dev)
-    dev_sstatus = self._ComputeBlockdevStatus(snode, instance, dev)
+  for idx, item in enumerate(container):
+    if item.uuid == identifier or item.name == identifier:
+      return (idx, item)
 
-    if dev.children:
-      dev_children = map(compat.partial(self._ComputeDiskStatusInner,
-                                        instance, snode),
-                         dev.children)
-    else:
-      dev_children = []
+  raise errors.OpPrereqError("Cannot find %s with identifier %s" %
+                             (kind, identifier), errors.ECODE_NOENT)
 
-    return {
-      "iv_name": dev.iv_name,
-      "dev_type": dev.dev_type,
-      "logical_id": dev.logical_id,
-      "physical_id": dev.physical_id,
-      "pstatus": dev_pstatus,
-      "sstatus": dev_sstatus,
-      "children": dev_children,
-      "mode": dev.mode,
-      "size": dev.size,
-      "name": dev.name,
-      "uuid": dev.uuid,
-      }
 
-  def Exec(self, feedback_fn):
-    """Gather and return data"""
-    result = {}
+def _ApplyContainerMods(kind, container, chgdesc, mods,
+                        create_fn, modify_fn, remove_fn):
+  """Applies descriptions in C{mods} to C{container}.
 
-    cluster = self.cfg.GetClusterInfo()
+  @type kind: string
+  @param kind: One-word item description
+  @type container: list
+  @param container: Container to modify
+  @type chgdesc: None or list
+  @param chgdesc: List of applied changes
+  @type mods: list
+  @param mods: Modifications as returned by L{_PrepareContainerMods}
+  @type create_fn: callable
+  @param create_fn: Callback for creating a new item (L{constants.DDM_ADD});
+    receives absolute item index, parameters and private data object as added
+    by L{_PrepareContainerMods}, returns tuple containing new item and changes
+    as list
+  @type modify_fn: callable
+  @param modify_fn: Callback for modifying an existing item
+    (L{constants.DDM_MODIFY}); receives absolute item index, item, parameters
+    and private data object as added by L{_PrepareContainerMods}, returns
+    changes as list
+  @type remove_fn: callable
+  @param remove_fn: Callback on removing item; receives absolute item index,
+    item and private data object as added by L{_PrepareContainerMods}
 
-    node_names = itertools.chain(*(i.all_nodes for i in self.wanted_instances))
-    nodes = dict(self.cfg.GetMultiNodeInfo(node_names))
+  """
+  for (op, identifier, params, private) in mods:
+    changes = None
 
-    groups = dict(self.cfg.GetMultiNodeGroupInfo(node.group
-                                                 for node in nodes.values()))
+    if op == constants.DDM_ADD:
+      # Calculate where item will be added
+      # When adding an item, identifier can only be an index
+      try:
+        idx = int(identifier)
+      except ValueError:
+        raise errors.OpPrereqError("Only possitive integer or -1 is accepted as"
+                                   " identifier for %s" % constants.DDM_ADD,
+                                   errors.ECODE_INVAL)
+      if idx == -1:
+        addidx = len(container)
+      else:
+        if idx < 0:
+          raise IndexError("Not accepting negative indices other than -1")
+        elif idx > len(container):
+          raise IndexError("Got %s index %s, but there are only %s" %
+                           (kind, idx, len(container)))
+        addidx = idx
 
-    group2name_fn = lambda uuid: groups[uuid].name
-    for instance in self.wanted_instances:
-      pnode = nodes[instance.primary_node]
+      if create_fn is None:
+        item = params
+      else:
+        (item, changes) = create_fn(addidx, params, private)
 
-      if self.op.static or pnode.offline:
-        remote_state = None
-        if pnode.offline:
-          self.LogWarning("Primary node %s is marked offline, returning static"
-                          " information only for instance %s" %
-                          (pnode.name, instance.name))
+      if idx == -1:
+        container.append(item)
       else:
-        remote_info = self.rpc.call_instance_info(instance.primary_node,
-                                                  instance.name,
-                                                  instance.hypervisor)
-        remote_info.Raise("Error checking node %s" % instance.primary_node)
-        remote_info = remote_info.payload
-        if remote_info and "state" in remote_info:
-          remote_state = "up"
-        else:
-          if instance.admin_state == constants.ADMINST_UP:
-            remote_state = "down"
-          else:
-            remote_state = instance.admin_state
-
-      disks = map(compat.partial(self._ComputeDiskStatus, instance, None),
-                  instance.disks)
-
-      snodes_group_uuids = [nodes[snode_name].group
-                            for snode_name in instance.secondary_nodes]
-
-      result[instance.name] = {
-        "name": instance.name,
-        "config_state": instance.admin_state,
-        "run_state": remote_state,
-        "pnode": instance.primary_node,
-        "pnode_group_uuid": pnode.group,
-        "pnode_group_name": group2name_fn(pnode.group),
-        "snodes": instance.secondary_nodes,
-        "snodes_group_uuids": snodes_group_uuids,
-        "snodes_group_names": map(group2name_fn, snodes_group_uuids),
-        "os": instance.os,
-        # this happens to be the same format used for hooks
-        "nics": _NICListToTuple(self, instance.nics),
-        "disk_template": instance.disk_template,
-        "disks": disks,
-        "hypervisor": instance.hypervisor,
-        "network_port": instance.network_port,
-        "hv_instance": instance.hvparams,
-        "hv_actual": cluster.FillHV(instance, skip_globals=True),
-        "be_instance": instance.beparams,
-        "be_actual": cluster.FillBE(instance),
-        "os_instance": instance.osparams,
-        "os_actual": cluster.SimpleFillOS(instance.os, instance.osparams),
-        "serial_no": instance.serial_no,
-        "mtime": instance.mtime,
-        "ctime": instance.ctime,
-        "uuid": instance.uuid,
-        }
+        assert idx >= 0
+        assert idx <= len(container)
+        # list.insert does so before the specified index
+        container.insert(idx, item)
+    else:
+      # Retrieve existing item
+      (absidx, item) = GetItemFromContainer(identifier, kind, container)
 
-    return result
+      if op == constants.DDM_REMOVE:
+        assert not params
 
+        if remove_fn is not None:
+          remove_fn(absidx, item, private)
 
-class LUInstanceRecreateDisks(LogicalUnit):
-  """Recreate an instance's missing disks.
+        changes = [("%s/%s" % (kind, absidx), "remove")]
 
-  """
-  HPATH = "instance-recreate-disks"
-  HTYPE = constants.HTYPE_INSTANCE
-  REQ_BGL = False
+        assert container[absidx] == item
+        del container[absidx]
+      elif op == constants.DDM_MODIFY:
+        if modify_fn is not None:
+          changes = modify_fn(absidx, item, params, private)
+      else:
+        raise errors.ProgrammerError("Unhandled operation '%s'" % op)
 
-  _MODIFYABLE = compat.UniqueFrozenset([
-    constants.IDISK_SIZE,
-    constants.IDISK_MODE,
-    ])
+    assert _TApplyContModsCbChanges(changes)
 
-  # New or changed disk parameters may have different semantics
-  assert constants.IDISK_PARAMS == (_MODIFYABLE | frozenset([
-    constants.IDISK_ADOPT,
+    if not (chgdesc is None or changes is None):
+      chgdesc.extend(changes)
 
-    # TODO: Implement support changing VG while recreating
-    constants.IDISK_VG,
-    constants.IDISK_METAVG,
-    constants.IDISK_PROVIDER,
-    constants.IDISK_NAME,
-    ]))
 
-  def _RunAllocator(self):
-    """Run the allocator based on input opcode.
+def _UpdateIvNames(base_index, disks):
+  """Updates the C{iv_name} attribute of disks.
 
-    """
-    be_full = self.cfg.GetClusterInfo().FillBE(self.instance)
-
-    # FIXME
-    # The allocator should actually run in "relocate" mode, but current
-    # allocators don't support relocating all the nodes of an instance at
-    # the same time. As a workaround we use "allocate" mode, but this is
-    # suboptimal for two reasons:
-    # - The instance name passed to the allocator is present in the list of
-    #   existing instances, so there could be a conflict within the
-    #   internal structures of the allocator. This doesn't happen with the
-    #   current allocators, but it's a liability.
-    # - The allocator counts the resources used by the instance twice: once
-    #   because the instance exists already, and once because it tries to
-    #   allocate a new instance.
-    # The allocator could choose some of the nodes on which the instance is
-    # running, but that's not a problem. If the instance nodes are broken,
-    # they should be already be marked as drained or offline, and hence
-    # skipped by the allocator. If instance disks have been lost for other
-    # reasons, then recreating the disks on the same nodes should be fine.
-    disk_template = self.instance.disk_template
-    spindle_use = be_full[constants.BE_SPINDLE_USE]
-    req = iallocator.IAReqInstanceAlloc(name=self.op.instance_name,
-                                        disk_template=disk_template,
-                                        tags=list(self.instance.GetTags()),
-                                        os=self.instance.os,
-                                        nics=[{}],
-                                        vcpus=be_full[constants.BE_VCPUS],
-                                        memory=be_full[constants.BE_MAXMEM],
-                                        spindle_use=spindle_use,
-                                        disks=[{constants.IDISK_SIZE: d.size,
-                                                constants.IDISK_MODE: d.mode}
-                                               for d in self.instance.disks],
-                                        hypervisor=self.instance.hypervisor,
-                                        node_whitelist=None)
-    ial = iallocator.IAllocator(self.cfg, self.rpc, req)
+  @type disks: list of L{objects.Disk}
 
-    ial.Run(self.op.iallocator)
+  """
+  for (idx, disk) in enumerate(disks):
+    disk.iv_name = "disk/%s" % (base_index + idx, )
 
-    assert req.RequiredNodes() == len(self.instance.all_nodes)
 
-    if not ial.success:
-      raise errors.OpPrereqError("Can't compute nodes using iallocator '%s':"
-                                 " %s" % (self.op.iallocator, ial.info),
-                                 errors.ECODE_NORES)
+class LUInstanceSetParams(LogicalUnit):
+  """Modifies an instances's parameters.
 
-    self.op.nodes = ial.result
-    self.LogInfo("Selected nodes for instance %s via iallocator %s: %s",
-                 self.op.instance_name, self.op.iallocator,
-                 utils.CommaJoin(ial.result))
-
-  def CheckArguments(self):
-    if self.op.disks and ht.TNonNegativeInt(self.op.disks[0]):
-      # Normalize and convert deprecated list of disk indices
-      self.op.disks = [(idx, {}) for idx in sorted(frozenset(self.op.disks))]
-
-    duplicates = utils.FindDuplicates(map(compat.fst, self.op.disks))
-    if duplicates:
-      raise errors.OpPrereqError("Some disks have been specified more than"
-                                 " once: %s" % utils.CommaJoin(duplicates),
-                                 errors.ECODE_INVAL)
-
-    # We don't want _CheckIAllocatorOrNode selecting the default iallocator
-    # when neither iallocator nor nodes are specified
-    if self.op.iallocator or self.op.nodes:
-      _CheckIAllocatorOrNode(self, "iallocator", "nodes")
-
-    for (idx, params) in self.op.disks:
-      utils.ForceDictType(params, constants.IDISK_PARAMS_TYPES)
-      unsupported = frozenset(params.keys()) - self._MODIFYABLE
-      if unsupported:
-        raise errors.OpPrereqError("Parameters for disk %s try to change"
-                                   " unmodifyable parameter(s): %s" %
-                                   (idx, utils.CommaJoin(unsupported)),
-                                   errors.ECODE_INVAL)
+  """
+  HPATH = "instance-modify"
+  HTYPE = constants.HTYPE_INSTANCE
+  REQ_BGL = False
 
-  def ExpandNames(self):
-    self._ExpandAndLockInstance()
-    self.recalculate_locks[locking.LEVEL_NODE] = constants.LOCKS_APPEND
+  @staticmethod
+  def _UpgradeDiskNicMods(kind, mods, verify_fn):
+    assert ht.TList(mods)
+    assert not mods or len(mods[0]) in (2, 3)
 
-    if self.op.nodes:
-      self.op.nodes = [_ExpandNodeName(self.cfg, n) for n in self.op.nodes]
-      self.needed_locks[locking.LEVEL_NODE] = list(self.op.nodes)
-    else:
-      self.needed_locks[locking.LEVEL_NODE] = []
-      if self.op.iallocator:
-        # iallocator will select a new node in the same group
-        self.needed_locks[locking.LEVEL_NODEGROUP] = []
-        self.needed_locks[locking.LEVEL_NODE_ALLOC] = locking.ALL_SET
+    if mods and len(mods[0]) == 2:
+      result = []
 
-    self.needed_locks[locking.LEVEL_NODE_RES] = []
+      addremove = 0
+      for op, params in mods:
+        if op in (constants.DDM_ADD, constants.DDM_REMOVE):
+          result.append((op, -1, params))
+          addremove += 1
 
-  def DeclareLocks(self, level):
-    if level == locking.LEVEL_NODEGROUP:
-      assert self.op.iallocator is not None
-      assert not self.op.nodes
-      assert not self.needed_locks[locking.LEVEL_NODEGROUP]
-      self.share_locks[locking.LEVEL_NODEGROUP] = 1
-      # Lock the primary group used by the instance optimistically; this
-      # requires going via the node before it's locked, requiring
-      # verification later on
-      self.needed_locks[locking.LEVEL_NODEGROUP] = \
-        self.cfg.GetInstanceNodeGroups(self.op.instance_name, primary_only=True)
+          if addremove > 1:
+            raise errors.OpPrereqError("Only one %s add or remove operation is"
+                                       " supported at a time" % kind,
+                                       errors.ECODE_INVAL)
+        else:
+          result.append((constants.DDM_MODIFY, op, params))
 
-    elif level == locking.LEVEL_NODE:
-      # If an allocator is used, then we lock all the nodes in the current
-      # instance group, as we don't know yet which ones will be selected;
-      # if we replace the nodes without using an allocator, locks are
-      # already declared in ExpandNames; otherwise, we need to lock all the
-      # instance nodes for disk re-creation
-      if self.op.iallocator:
-        assert not self.op.nodes
-        assert not self.needed_locks[locking.LEVEL_NODE]
-        assert len(self.owned_locks(locking.LEVEL_NODEGROUP)) == 1
-
-        # Lock member nodes of the group of the primary node
-        for group_uuid in self.owned_locks(locking.LEVEL_NODEGROUP):
-          self.needed_locks[locking.LEVEL_NODE].extend(
-            self.cfg.GetNodeGroup(group_uuid).members)
-
-        assert locking.NAL in self.owned_locks(locking.LEVEL_NODE_ALLOC)
-      elif not self.op.nodes:
-        self._LockInstancesNodes(primary_only=False)
-    elif level == locking.LEVEL_NODE_RES:
-      # Copy node locks
-      self.needed_locks[locking.LEVEL_NODE_RES] = \
-        _CopyLockList(self.needed_locks[locking.LEVEL_NODE])
+      assert verify_fn(result)
+    else:
+      result = mods
 
-  def BuildHooksEnv(self):
-    """Build hooks env.
+    return result
 
-    This runs on master, primary and secondary nodes of the instance.
+  @staticmethod
+  def _CheckMods(kind, mods, key_types, item_fn):
+    """Ensures requested disk/NIC modifications are valid.
 
     """
-    return _BuildInstanceHookEnvByObject(self, self.instance)
-
-  def BuildHooksNodes(self):
-    """Build hooks nodes.
+    for (op, _, params) in mods:
+      assert ht.TDict(params)
 
-    """
-    nl = [self.cfg.GetMasterNode()] + list(self.instance.all_nodes)
-    return (nl, nl)
+      # If 'key_types' is an empty dict, we assume we have an
+      # 'ext' template and thus do not ForceDictType
+      if key_types:
+        utils.ForceDictType(params, key_types)
 
-  def CheckPrereq(self):
-    """Check prerequisites.
+      if op == constants.DDM_REMOVE:
+        if params:
+          raise errors.OpPrereqError("No settings should be passed when"
+                                     " removing a %s" % kind,
+                                     errors.ECODE_INVAL)
+      elif op in (constants.DDM_ADD, constants.DDM_MODIFY):
+        item_fn(op, params)
+      else:
+        raise errors.ProgrammerError("Unhandled operation '%s'" % op)
 
-    This checks that the instance is in the cluster and is not running.
+  @staticmethod
+  def _VerifyDiskModification(op, params):
+    """Verifies a disk modification.
 
     """
-    instance = self.cfg.GetInstanceInfo(self.op.instance_name)
-    assert instance is not None, \
-      "Cannot retrieve locked instance %s" % self.op.instance_name
-    if self.op.nodes:
-      if len(self.op.nodes) != len(instance.all_nodes):
-        raise errors.OpPrereqError("Instance %s currently has %d nodes, but"
-                                   " %d replacement nodes were specified" %
-                                   (instance.name, len(instance.all_nodes),
-                                    len(self.op.nodes)),
+    if op == constants.DDM_ADD:
+      mode = params.setdefault(constants.IDISK_MODE, constants.DISK_RDWR)
+      if mode not in constants.DISK_ACCESS_SET:
+        raise errors.OpPrereqError("Invalid disk access mode '%s'" % mode,
                                    errors.ECODE_INVAL)
-      assert instance.disk_template != constants.DT_DRBD8 or \
-             len(self.op.nodes) == 2
-      assert instance.disk_template != constants.DT_PLAIN or \
-             len(self.op.nodes) == 1
-      primary_node = self.op.nodes[0]
-    else:
-      primary_node = instance.primary_node
-    if not self.op.iallocator:
-      _CheckNodeOnline(self, primary_node)
-
-    if instance.disk_template == constants.DT_DISKLESS:
-      raise errors.OpPrereqError("Instance '%s' has no disks" %
-                                 self.op.instance_name, errors.ECODE_INVAL)
-
-    # Verify if node group locks are still correct
-    owned_groups = self.owned_locks(locking.LEVEL_NODEGROUP)
-    if owned_groups:
-      # Node group locks are acquired only for the primary node (and only
-      # when the allocator is used)
-      _CheckInstanceNodeGroups(self.cfg, self.op.instance_name, owned_groups,
-                               primary_only=True)
-
-    # if we replace nodes *and* the old primary is offline, we don't
-    # check the instance state
-    old_pnode = self.cfg.GetNodeInfo(instance.primary_node)
-    if not ((self.op.iallocator or self.op.nodes) and old_pnode.offline):
-      _CheckInstanceState(self, instance, INSTANCE_NOT_RUNNING,
-                          msg="cannot recreate disks")
-
-    if self.op.disks:
-      self.disks = dict(self.op.disks)
-    else:
-      self.disks = dict((idx, {}) for idx in range(len(instance.disks)))
-
-    maxidx = max(self.disks.keys())
-    if maxidx >= len(instance.disks):
-      raise errors.OpPrereqError("Invalid disk index '%s'" % maxidx,
-                                 errors.ECODE_INVAL)
-
-    if ((self.op.nodes or self.op.iallocator) and
-         sorted(self.disks.keys()) != range(len(instance.disks))):
-      raise errors.OpPrereqError("Can't recreate disks partially and"
-                                 " change the nodes at the same time",
-                                 errors.ECODE_INVAL)
-
-    self.instance = instance
-
-    if self.op.iallocator:
-      self._RunAllocator()
-      # Release unneeded node and node resource locks
-      _ReleaseLocks(self, locking.LEVEL_NODE, keep=self.op.nodes)
-      _ReleaseLocks(self, locking.LEVEL_NODE_RES, keep=self.op.nodes)
-      _ReleaseLocks(self, locking.LEVEL_NODE_ALLOC)
-
-    assert not self.glm.is_owned(locking.LEVEL_NODE_ALLOC)
-
-  def Exec(self, feedback_fn):
-    """Recreate the disks.
-
-    """
-    instance = self.instance
 
-    assert (self.owned_locks(locking.LEVEL_NODE) ==
-            self.owned_locks(locking.LEVEL_NODE_RES))
-
-    to_skip = []
-    mods = [] # keeps track of needed changes
+      size = params.get(constants.IDISK_SIZE, None)
+      if size is None:
+        raise errors.OpPrereqError("Required disk parameter '%s' missing" %
+                                   constants.IDISK_SIZE, errors.ECODE_INVAL)
 
-    for idx, disk in enumerate(instance.disks):
       try:
-        changes = self.disks[idx]
-      except KeyError:
-        # Disk should not be recreated
-        to_skip.append(idx)
-        continue
-
-      # update secondaries for disks, if needed
-      if self.op.nodes and disk.dev_type == constants.LD_DRBD8:
-        # need to update the nodes and minors
-        assert len(self.op.nodes) == 2
-        assert len(disk.logical_id) == 6 # otherwise disk internals
-                                         # have changed
-        (_, _, old_port, _, _, old_secret) = disk.logical_id
-        new_minors = self.cfg.AllocateDRBDMinor(self.op.nodes, instance.name)
-        new_id = (self.op.nodes[0], self.op.nodes[1], old_port,
-                  new_minors[0], new_minors[1], old_secret)
-        assert len(disk.logical_id) == len(new_id)
-      else:
-        new_id = None
-
-      mods.append((idx, new_id, changes))
-
-    # now that we have passed all asserts above, we can apply the mods
-    # in a single run (to avoid partial changes)
-    for idx, new_id, changes in mods:
-      disk = instance.disks[idx]
-      if new_id is not None:
-        assert disk.dev_type == constants.LD_DRBD8
-        disk.logical_id = new_id
-      if changes:
-        disk.Update(size=changes.get(constants.IDISK_SIZE, None),
-                    mode=changes.get(constants.IDISK_MODE, None))
-
-    # change primary node, if needed
-    if self.op.nodes:
-      instance.primary_node = self.op.nodes[0]
-      self.LogWarning("Changing the instance's nodes, you will have to"
-                      " remove any disks left on the older nodes manually")
+        size = int(size)
+      except (TypeError, ValueError), err:
+        raise errors.OpPrereqError("Invalid disk size parameter: %s" % err,
+                                   errors.ECODE_INVAL)
 
-    if self.op.nodes:
-      self.cfg.Update(instance, feedback_fn)
+      params[constants.IDISK_SIZE] = size
+      name = params.get(constants.IDISK_NAME, None)
+      if name is not None and name.lower() == constants.VALUE_NONE:
+        params[constants.IDISK_NAME] = None
 
-    # All touched nodes must be locked
-    mylocks = self.owned_locks(locking.LEVEL_NODE)
-    assert mylocks.issuperset(frozenset(instance.all_nodes))
-    _CreateDisks(self, instance, to_skip=to_skip)
+    elif op == constants.DDM_MODIFY:
+      if constants.IDISK_SIZE in params:
+        raise errors.OpPrereqError("Disk size change not possible, use"
+                                   " grow-disk", errors.ECODE_INVAL)
+      if len(params) > 2:
+        raise errors.OpPrereqError("Disk modification doesn't support"
+                                   " additional arbitrary parameters",
+                                   errors.ECODE_INVAL)
+      name = params.get(constants.IDISK_NAME, None)
+      if name is not None and name.lower() == constants.VALUE_NONE:
+        params[constants.IDISK_NAME] = None
 
+  @staticmethod
+  def _VerifyNicModification(op, params):
+    """Verifies a network interface modification.
 
-def _SafeShutdownInstanceDisks(lu, instance, disks=None):
-  """Shutdown block devices of an instance.
+    """
+    if op in (constants.DDM_ADD, constants.DDM_MODIFY):
+      ip = params.get(constants.INIC_IP, None)
+      name = params.get(constants.INIC_NAME, None)
+      req_net = params.get(constants.INIC_NETWORK, None)
+      link = params.get(constants.NIC_LINK, None)
+      mode = params.get(constants.NIC_MODE, None)
+      if name is not None and name.lower() == constants.VALUE_NONE:
+        params[constants.INIC_NAME] = None
+      if req_net is not None:
+        if req_net.lower() == constants.VALUE_NONE:
+          params[constants.INIC_NETWORK] = None
+          req_net = None
+        elif link is not None or mode is not None:
+          raise errors.OpPrereqError("If network is given"
+                                     " mode or link should not",
+                                     errors.ECODE_INVAL)
 
-  This function checks if an instance is running, before calling
-  _ShutdownInstanceDisks.
+      if op == constants.DDM_ADD:
+        macaddr = params.get(constants.INIC_MAC, None)
+        if macaddr is None:
+          params[constants.INIC_MAC] = constants.VALUE_AUTO
 
-  """
-  _CheckInstanceState(lu, instance, INSTANCE_DOWN, msg="cannot shutdown disks")
-  _ShutdownInstanceDisks(lu, instance, disks=disks)
+      if ip is not None:
+        if ip.lower() == constants.VALUE_NONE:
+          params[constants.INIC_IP] = None
+        else:
+          if ip.lower() == constants.NIC_IP_POOL:
+            if op == constants.DDM_ADD and req_net is None:
+              raise errors.OpPrereqError("If ip=pool, parameter network"
+                                         " cannot be none",
+                                         errors.ECODE_INVAL)
+          else:
+            if not netutils.IPAddress.IsValid(ip):
+              raise errors.OpPrereqError("Invalid IP address '%s'" % ip,
+                                         errors.ECODE_INVAL)
 
+      if constants.INIC_MAC in params:
+        macaddr = params[constants.INIC_MAC]
+        if macaddr not in (constants.VALUE_AUTO, constants.VALUE_GENERATE):
+          macaddr = utils.NormalizeAndValidateMac(macaddr)
 
-def _DiskSizeInBytesToMebibytes(lu, size):
-  """Converts a disk size in bytes to mebibytes.
+        if op == constants.DDM_MODIFY and macaddr == constants.VALUE_AUTO:
+          raise errors.OpPrereqError("'auto' is not a valid MAC address when"
+                                     " modifying an existing NIC",
+                                     errors.ECODE_INVAL)
 
-  Warns and rounds up if the size isn't an even multiple of 1 MiB.
+  def CheckArguments(self):
+    if not (self.op.nics or self.op.disks or self.op.disk_template or
+            self.op.hvparams or self.op.beparams or self.op.os_name or
+            self.op.osparams or self.op.offline is not None or
+            self.op.runtime_mem or self.op.pnode):
+      raise errors.OpPrereqError("No changes submitted", errors.ECODE_INVAL)
 
-  """
-  (mib, remainder) = divmod(size, 1024 * 1024)
+    if self.op.hvparams:
+      CheckParamsNotGlobal(self.op.hvparams, constants.HVC_GLOBALS,
+                           "hypervisor", "instance", "cluster")
 
-  if remainder != 0:
-    lu.LogWarning("Disk size is not an even multiple of 1 MiB; rounding up"
-                  " to not overwrite existing data (%s bytes will not be"
-                  " wiped)", (1024 * 1024) - remainder)
-    mib += 1
+    self.op.disks = self._UpgradeDiskNicMods(
+      "disk", self.op.disks, opcodes.OpInstanceSetParams.TestDiskModifications)
+    self.op.nics = self._UpgradeDiskNicMods(
+      "NIC", self.op.nics, opcodes.OpInstanceSetParams.TestNicModifications)
 
-  return mib
+    if self.op.disks and self.op.disk_template is not None:
+      raise errors.OpPrereqError("Disk template conversion and other disk"
+                                 " changes not supported at the same time",
+                                 errors.ECODE_INVAL)
 
+    if (self.op.disk_template and
+        self.op.disk_template in constants.DTS_INT_MIRROR and
+        self.op.remote_node is None):
+      raise errors.OpPrereqError("Changing the disk template to a mirrored"
+                                 " one requires specifying a secondary node",
+                                 errors.ECODE_INVAL)
 
-class LUInstanceGrowDisk(LogicalUnit):
-  """Grow a disk of an instance.
+    # Check NIC modifications
+    self._CheckMods("NIC", self.op.nics, constants.INIC_PARAMS_TYPES,
+                    self._VerifyNicModification)
 
-  """
-  HPATH = "disk-grow"
-  HTYPE = constants.HTYPE_INSTANCE
-  REQ_BGL = False
+    if self.op.pnode:
+      self.op.pnode = ExpandNodeName(self.cfg, self.op.pnode)
 
   def ExpandNames(self):
     self._ExpandAndLockInstance()
+    self.needed_locks[locking.LEVEL_NODEGROUP] = []
+    # Can't even acquire node locks in shared mode as upcoming changes in
+    # Ganeti 2.6 will start to modify the node object on disk conversion
     self.needed_locks[locking.LEVEL_NODE] = []
     self.needed_locks[locking.LEVEL_NODE_RES] = []
     self.recalculate_locks[locking.LEVEL_NODE] = constants.LOCKS_REPLACE
-    self.recalculate_locks[locking.LEVEL_NODE_RES] = constants.LOCKS_REPLACE
+    # Look node group to look up the ipolicy
+    self.share_locks[locking.LEVEL_NODEGROUP] = 1
 
   def DeclareLocks(self, level):
-    if level == locking.LEVEL_NODE:
+    if level == locking.LEVEL_NODEGROUP:
+      assert not self.needed_locks[locking.LEVEL_NODEGROUP]
+      # Acquire locks for the instance's nodegroups optimistically. Needs
+      # to be verified in CheckPrereq
+      self.needed_locks[locking.LEVEL_NODEGROUP] = \
+        self.cfg.GetInstanceNodeGroups(self.op.instance_name)
+    elif level == locking.LEVEL_NODE:
       self._LockInstancesNodes()
-    elif level == locking.LEVEL_NODE_RES:
+      if self.op.disk_template and self.op.remote_node:
+        self.op.remote_node = ExpandNodeName(self.cfg, self.op.remote_node)
+        self.needed_locks[locking.LEVEL_NODE].append(self.op.remote_node)
+    elif level == locking.LEVEL_NODE_RES and self.op.disk_template:
       # Copy node locks
       self.needed_locks[locking.LEVEL_NODE_RES] = \
-        _CopyLockList(self.needed_locks[locking.LEVEL_NODE])
+        CopyLockList(self.needed_locks[locking.LEVEL_NODE])
 
   def BuildHooksEnv(self):
     """Build hooks env.
 
-    This runs on the master, the primary and all the secondaries.
+    This runs on the master, primary and secondaries.
 
     """
-    env = {
-      "DISK": self.op.disk,
-      "AMOUNT": self.op.amount,
-      "ABSOLUTE": self.op.absolute,
-      }
-    env.update(_BuildInstanceHookEnvByObject(self, self.instance))
+    args = {}
+    if constants.BE_MINMEM in self.be_new:
+      args["minmem"] = self.be_new[constants.BE_MINMEM]
+    if constants.BE_MAXMEM in self.be_new:
+      args["maxmem"] = self.be_new[constants.BE_MAXMEM]
+    if constants.BE_VCPUS in self.be_new:
+      args["vcpus"] = self.be_new[constants.BE_VCPUS]
+    # TODO: export disk changes. Note: _BuildInstanceHookEnv* don't export disk
+    # information at all.
+
+    if self._new_nics is not None:
+      nics = []
+
+      for nic in self._new_nics:
+        n = copy.deepcopy(nic)
+        nicparams = self.cluster.SimpleFillNIC(n.nicparams)
+        n.nicparams = nicparams
+        nics.append(NICToTuple(self, n))
+
+      args["nics"] = nics
+
+    env = BuildInstanceHookEnvByObject(self, self.instance, override=args)
+    if self.op.disk_template:
+      env["NEW_DISK_TEMPLATE"] = self.op.disk_template
+    if self.op.runtime_mem:
+      env["RUNTIME_MEMORY"] = self.op.runtime_mem
+
     return env
 
   def BuildHooksNodes(self):
@@ -3516,4170 +2438,1056 @@ class LUInstanceGrowDisk(LogicalUnit):
     nl = [self.cfg.GetMasterNode()] + list(self.instance.all_nodes)
     return (nl, nl)
 
-  def CheckPrereq(self):
-    """Check prerequisites.
-
-    This checks that the instance is in the cluster.
+  def _PrepareNicModification(self, params, private, old_ip, old_net_uuid,
+                              old_params, cluster, pnode):
 
-    """
-    instance = self.cfg.GetInstanceInfo(self.op.instance_name)
-    assert instance is not None, \
-      "Cannot retrieve locked instance %s" % self.op.instance_name
-    nodenames = list(instance.all_nodes)
-    for node in nodenames:
-      _CheckNodeOnline(self, node)
+    update_params_dict = dict([(key, params[key])
+                               for key in constants.NICS_PARAMETERS
+                               if key in params])
 
-    self.instance = instance
+    req_link = update_params_dict.get(constants.NIC_LINK, None)
+    req_mode = update_params_dict.get(constants.NIC_MODE, None)
 
-    if instance.disk_template not in constants.DTS_GROWABLE:
-      raise errors.OpPrereqError("Instance's disk layout does not support"
-                                 " growing", errors.ECODE_INVAL)
+    new_net_uuid = None
+    new_net_uuid_or_name = params.get(constants.INIC_NETWORK, old_net_uuid)
+    if new_net_uuid_or_name:
+      new_net_uuid = self.cfg.LookupNetwork(new_net_uuid_or_name)
+      new_net_obj = self.cfg.GetNetwork(new_net_uuid)
 
-    self.disk = instance.FindDisk(self.op.disk)
+    if old_net_uuid:
+      old_net_obj = self.cfg.GetNetwork(old_net_uuid)
 
-    if self.op.absolute:
-      self.target = self.op.amount
-      self.delta = self.target - self.disk.size
-      if self.delta < 0:
-        raise errors.OpPrereqError("Requested size (%s) is smaller than "
-                                   "current disk size (%s)" %
-                                   (utils.FormatUnit(self.target, "h"),
-                                    utils.FormatUnit(self.disk.size, "h")),
-                                   errors.ECODE_STATE)
+    if new_net_uuid:
+      netparams = self.cfg.GetGroupNetParams(new_net_uuid, pnode)
+      if not netparams:
+        raise errors.OpPrereqError("No netparams found for the network"
+                                   " %s, probably not connected" %
+                                   new_net_obj.name, errors.ECODE_INVAL)
+      new_params = dict(netparams)
     else:
-      self.delta = self.op.amount
-      self.target = self.disk.size + self.delta
-      if self.delta < 0:
-        raise errors.OpPrereqError("Requested increment (%s) is negative" %
-                                   utils.FormatUnit(self.delta, "h"),
-                                   errors.ECODE_INVAL)
+      new_params = GetUpdatedParams(old_params, update_params_dict)
 
-    self._CheckDiskSpace(nodenames, self.disk.ComputeGrowth(self.delta))
-
-  def _CheckDiskSpace(self, nodenames, req_vgspace):
-    template = self.instance.disk_template
-    if template not in (constants.DTS_NO_FREE_SPACE_CHECK):
-      # TODO: check the free disk space for file, when that feature will be
-      # supported
-      nodes = map(self.cfg.GetNodeInfo, nodenames)
-      es_nodes = filter(lambda n: _IsExclusiveStorageEnabledNode(self.cfg, n),
-                        nodes)
-      if es_nodes:
-        # With exclusive storage we need to something smarter than just looking
-        # at free space; for now, let's simply abort the operation.
-        raise errors.OpPrereqError("Cannot grow disks when exclusive_storage"
-                                   " is enabled", errors.ECODE_STATE)
-      _CheckNodesFreeDiskPerVG(self, nodenames, req_vgspace)
-
-  def Exec(self, feedback_fn):
-    """Execute disk grow.
-
-    """
-    instance = self.instance
-    disk = self.disk
+    utils.ForceDictType(new_params, constants.NICS_PARAMETER_TYPES)
 
-    assert set([instance.name]) == self.owned_locks(locking.LEVEL_INSTANCE)
-    assert (self.owned_locks(locking.LEVEL_NODE) ==
-            self.owned_locks(locking.LEVEL_NODE_RES))
+    new_filled_params = cluster.SimpleFillNIC(new_params)
+    objects.NIC.CheckParameterSyntax(new_filled_params)
 
-    wipe_disks = self.cfg.GetClusterInfo().prealloc_wipe_disks
+    new_mode = new_filled_params[constants.NIC_MODE]
+    if new_mode == constants.NIC_MODE_BRIDGED:
+      bridge = new_filled_params[constants.NIC_LINK]
+      msg = self.rpc.call_bridges_exist(pnode, [bridge]).fail_msg
+      if msg:
+        msg = "Error checking bridges on node '%s': %s" % (pnode, msg)
+        if self.op.force:
+          self.warn.append(msg)
+        else:
+          raise errors.OpPrereqError(msg, errors.ECODE_ENVIRON)
 
-    disks_ok, _ = _AssembleInstanceDisks(self, self.instance, disks=[disk])
-    if not disks_ok:
-      raise errors.OpExecError("Cannot activate block device to grow")
+    elif new_mode == constants.NIC_MODE_ROUTED:
+      ip = params.get(constants.INIC_IP, old_ip)
+      if ip is None:
+        raise errors.OpPrereqError("Cannot set the NIC IP address to None"
+                                   " on a routed NIC", errors.ECODE_INVAL)
 
-    feedback_fn("Growing disk %s of instance '%s' by %s to %s" %
-                (self.op.disk, instance.name,
-                 utils.FormatUnit(self.delta, "h"),
-                 utils.FormatUnit(self.target, "h")))
+    elif new_mode == constants.NIC_MODE_OVS:
+      # TODO: check OVS link
+      self.LogInfo("OVS links are currently not checked for correctness")
 
-    # First run all grow ops in dry-run mode
-    for node in instance.all_nodes:
-      self.cfg.SetDiskID(disk, node)
-      result = self.rpc.call_blockdev_grow(node, (disk, instance), self.delta,
-                                           True, True)
-      result.Raise("Dry-run grow request failed to node %s" % node)
+    if constants.INIC_MAC in params:
+      mac = params[constants.INIC_MAC]
+      if mac is None:
+        raise errors.OpPrereqError("Cannot unset the NIC MAC address",
+                                   errors.ECODE_INVAL)
+      elif mac in (constants.VALUE_AUTO, constants.VALUE_GENERATE):
+        # otherwise generate the MAC address
+        params[constants.INIC_MAC] = \
+          self.cfg.GenerateMAC(new_net_uuid, self.proc.GetECId())
+      else:
+        # or validate/reserve the current one
+        try:
+          self.cfg.ReserveMAC(mac, self.proc.GetECId())
+        except errors.ReservationError:
+          raise errors.OpPrereqError("MAC address '%s' already in use"
+                                     " in cluster" % mac,
+                                     errors.ECODE_NOTUNIQUE)
+    elif new_net_uuid != old_net_uuid:
 
-    if wipe_disks:
-      # Get disk size from primary node for wiping
-      result = self.rpc.call_blockdev_getsize(instance.primary_node, [disk])
-      result.Raise("Failed to retrieve disk size from node '%s'" %
-                   instance.primary_node)
+      def get_net_prefix(net_uuid):
+        mac_prefix = None
+        if net_uuid:
+          nobj = self.cfg.GetNetwork(net_uuid)
+          mac_prefix = nobj.mac_prefix
 
-      (disk_size_in_bytes, ) = result.payload
+        return mac_prefix
 
-      if disk_size_in_bytes is None:
-        raise errors.OpExecError("Failed to retrieve disk size from primary"
-                                 " node '%s'" % instance.primary_node)
+      new_prefix = get_net_prefix(new_net_uuid)
+      old_prefix = get_net_prefix(old_net_uuid)
+      if old_prefix != new_prefix:
+        params[constants.INIC_MAC] = \
+          self.cfg.GenerateMAC(new_net_uuid, self.proc.GetECId())
 
-      old_disk_size = _DiskSizeInBytesToMebibytes(self, disk_size_in_bytes)
+    # if there is a change in (ip, network) tuple
+    new_ip = params.get(constants.INIC_IP, old_ip)
+    if (new_ip, new_net_uuid) != (old_ip, old_net_uuid):
+      if new_ip:
+        # if IP is pool then require a network and generate one IP
+        if new_ip.lower() == constants.NIC_IP_POOL:
+          if new_net_uuid:
+            try:
+              new_ip = self.cfg.GenerateIp(new_net_uuid, self.proc.GetECId())
+            except errors.ReservationError:
+              raise errors.OpPrereqError("Unable to get a free IP"
+                                         " from the address pool",
+                                         errors.ECODE_STATE)
+            self.LogInfo("Chose IP %s from network %s",
+                         new_ip,
+                         new_net_obj.name)
+            params[constants.INIC_IP] = new_ip
+          else:
+            raise errors.OpPrereqError("ip=pool, but no network found",
+                                       errors.ECODE_INVAL)
+        # Reserve new IP if in the new network if any
+        elif new_net_uuid:
+          try:
+            self.cfg.ReserveIp(new_net_uuid, new_ip, self.proc.GetECId())
+            self.LogInfo("Reserving IP %s in network %s",
+                         new_ip, new_net_obj.name)
+          except errors.ReservationError:
+            raise errors.OpPrereqError("IP %s not available in network %s" %
+                                       (new_ip, new_net_obj.name),
+                                       errors.ECODE_NOTUNIQUE)
+        # new network is None so check if new IP is a conflicting IP
+        elif self.op.conflicts_check:
+          _CheckForConflictingIp(self, new_ip, pnode)
 
-      assert old_disk_size >= disk.size, \
-        ("Retrieved disk size too small (got %s, should be at least %s)" %
-         (old_disk_size, disk.size))
-    else:
-      old_disk_size = None
+      # release old IP if old network is not None
+      if old_ip and old_net_uuid:
+        try:
+          self.cfg.ReleaseIp(old_net_uuid, old_ip, self.proc.GetECId())
+        except errors.AddressPoolError:
+          logging.warning("Release IP %s not contained in network %s",
+                          old_ip, old_net_obj.name)
 
-    # We know that (as far as we can test) operations across different
-    # nodes will succeed, time to run it for real on the backing storage
-    for node in instance.all_nodes:
-      self.cfg.SetDiskID(disk, node)
-      result = self.rpc.call_blockdev_grow(node, (disk, instance), self.delta,
-                                           False, True)
-      result.Raise("Grow request failed to node %s" % node)
-
-    # And now execute it for logical storage, on the primary node
-    node = instance.primary_node
-    self.cfg.SetDiskID(disk, node)
-    result = self.rpc.call_blockdev_grow(node, (disk, instance), self.delta,
-                                         False, False)
-    result.Raise("Grow request failed to node %s" % node)
-
-    disk.RecordGrow(self.delta)
-    self.cfg.Update(instance, feedback_fn)
+    # there are no changes in (ip, network) tuple and old network is not None
+    elif (old_net_uuid is not None and
+          (req_link is not None or req_mode is not None)):
+      raise errors.OpPrereqError("Not allowed to change link or mode of"
+                                 " a NIC that is connected to a network",
+                                 errors.ECODE_INVAL)
 
-    # Changes have been recorded, release node lock
-    _ReleaseLocks(self, locking.LEVEL_NODE)
+    private.params = new_params
+    private.filled = new_filled_params
 
-    # Downgrade lock while waiting for sync
-    self.glm.downgrade(locking.LEVEL_INSTANCE)
+  def _PreCheckDiskTemplate(self, pnode_info):
+    """CheckPrereq checks related to a new disk template."""
+    # Arguments are passed to avoid configuration lookups
+    instance = self.instance
+    pnode = instance.primary_node
+    cluster = self.cluster
+    if instance.disk_template == self.op.disk_template:
+      raise errors.OpPrereqError("Instance already has disk template %s" %
+                                 instance.disk_template, errors.ECODE_INVAL)
 
-    assert wipe_disks ^ (old_disk_size is None)
+    if (instance.disk_template,
+        self.op.disk_template) not in self._DISK_CONVERSIONS:
+      raise errors.OpPrereqError("Unsupported disk template conversion from"
+                                 " %s to %s" % (instance.disk_template,
+                                                self.op.disk_template),
+                                 errors.ECODE_INVAL)
+    CheckInstanceState(self, instance, INSTANCE_DOWN,
+                       msg="cannot change disk template")
+    if self.op.disk_template in constants.DTS_INT_MIRROR:
+      if self.op.remote_node == pnode:
+        raise errors.OpPrereqError("Given new secondary node %s is the same"
+                                   " as the primary node of the instance" %
+                                   self.op.remote_node, errors.ECODE_STATE)
+      CheckNodeOnline(self, self.op.remote_node)
+      CheckNodeNotDrained(self, self.op.remote_node)
+      # FIXME: here we assume that the old instance type is DT_PLAIN
+      assert instance.disk_template == constants.DT_PLAIN
+      disks = [{constants.IDISK_SIZE: d.size,
+                constants.IDISK_VG: d.logical_id[0]}
+               for d in instance.disks]
+      required = ComputeDiskSizePerVG(self.op.disk_template, disks)
+      CheckNodesFreeDiskPerVG(self, [self.op.remote_node], required)
 
-    if wipe_disks:
-      assert instance.disks[self.op.disk] == disk
+      snode_info = self.cfg.GetNodeInfo(self.op.remote_node)
+      snode_group = self.cfg.GetNodeGroup(snode_info.group)
+      ipolicy = ganeti.masterd.instance.CalculateGroupIPolicy(cluster,
+                                                              snode_group)
+      CheckTargetNodeIPolicy(self, ipolicy, instance, snode_info, self.cfg,
+                             ignore=self.op.ignore_ipolicy)
+      if pnode_info.group != snode_info.group:
+        self.LogWarning("The primary and secondary nodes are in two"
+                        " different node groups; the disk parameters"
+                        " from the first disk's node group will be"
+                        " used")
 
-      # Wipe newly added disk space
-      _WipeDisks(self, instance,
-                 disks=[(self.op.disk, disk, old_disk_size)])
+    if not self.op.disk_template in constants.DTS_EXCL_STORAGE:
+      # Make sure none of the nodes require exclusive storage
+      nodes = [pnode_info]
+      if self.op.disk_template in constants.DTS_INT_MIRROR:
+        assert snode_info
+        nodes.append(snode_info)
+      has_es = lambda n: IsExclusiveStorageEnabledNode(self.cfg, n)
+      if compat.any(map(has_es, nodes)):
+        errmsg = ("Cannot convert disk template from %s to %s when exclusive"
+                  " storage is enabled" % (instance.disk_template,
+                                           self.op.disk_template))
+        raise errors.OpPrereqError(errmsg, errors.ECODE_STATE)
 
-    if self.op.wait_for_sync:
-      disk_abort = not _WaitForSync(self, instance, disks=[disk])
-      if disk_abort:
-        self.LogWarning("Disk syncing has not returned a good status; check"
-                        " the instance")
-      if instance.admin_state != constants.ADMINST_UP:
-        _SafeShutdownInstanceDisks(self, instance, disks=[disk])
-    elif instance.admin_state != constants.ADMINST_UP:
-      self.LogWarning("Not shutting down the disk even if the instance is"
-                      " not supposed to be running because no wait for"
-                      " sync mode was requested")
+  def CheckPrereq(self):
+    """Check prerequisites.
 
-    assert self.owned_locks(locking.LEVEL_NODE_RES)
-    assert set([instance.name]) == self.owned_locks(locking.LEVEL_INSTANCE)
+    This only checks the instance list against the existing names.
 
+    """
+    assert self.op.instance_name in self.owned_locks(locking.LEVEL_INSTANCE)
+    instance = self.instance = self.cfg.GetInstanceInfo(self.op.instance_name)
 
-class LUInstanceReplaceDisks(LogicalUnit):
-  """Replace the disks of an instance.
+    cluster = self.cluster = self.cfg.GetClusterInfo()
+    assert self.instance is not None, \
+      "Cannot retrieve locked instance %s" % self.op.instance_name
 
-  """
-  HPATH = "mirrors-replace"
-  HTYPE = constants.HTYPE_INSTANCE
-  REQ_BGL = False
+    pnode = instance.primary_node
 
-  def CheckArguments(self):
-    """Check arguments.
+    self.warn = []
 
-    """
-    remote_node = self.op.remote_node
-    ialloc = self.op.iallocator
-    if self.op.mode == constants.REPLACE_DISK_CHG:
-      if remote_node is None and ialloc is None:
-        raise errors.OpPrereqError("When changing the secondary either an"
-                                   " iallocator script must be used or the"
-                                   " new node given", errors.ECODE_INVAL)
-      else:
-        _CheckIAllocatorOrNode(self, "iallocator", "remote_node")
+    if (self.op.pnode is not None and self.op.pnode != pnode and
+        not self.op.force):
+      # verify that the instance is not up
+      instance_info = self.rpc.call_instance_info(pnode, instance.name,
+                                                  instance.hypervisor)
+      if instance_info.fail_msg:
+        self.warn.append("Can't get instance runtime information: %s" %
+                         instance_info.fail_msg)
+      elif instance_info.payload:
+        raise errors.OpPrereqError("Instance is still running on %s" % pnode,
+                                   errors.ECODE_STATE)
 
-    elif remote_node is not None or ialloc is not None:
-      # Not replacing the secondary
-      raise errors.OpPrereqError("The iallocator and new node options can"
-                                 " only be used when changing the"
-                                 " secondary node", errors.ECODE_INVAL)
+    assert pnode in self.owned_locks(locking.LEVEL_NODE)
+    nodelist = list(instance.all_nodes)
+    pnode_info = self.cfg.GetNodeInfo(pnode)
+    self.diskparams = self.cfg.GetInstanceDiskParams(instance)
 
-  def ExpandNames(self):
-    self._ExpandAndLockInstance()
+    #_CheckInstanceNodeGroups(self.cfg, self.op.instance_name, owned_groups)
+    assert pnode_info.group in self.owned_locks(locking.LEVEL_NODEGROUP)
+    group_info = self.cfg.GetNodeGroup(pnode_info.group)
 
-    assert locking.LEVEL_NODE not in self.needed_locks
-    assert locking.LEVEL_NODE_RES not in self.needed_locks
-    assert locking.LEVEL_NODEGROUP not in self.needed_locks
+    # dictionary with instance information after the modification
+    ispec = {}
 
-    assert self.op.iallocator is None or self.op.remote_node is None, \
-      "Conflicting options"
+    # Check disk modifications. This is done here and not in CheckArguments
+    # (as with NICs), because we need to know the instance's disk template
+    if instance.disk_template == constants.DT_EXT:
+      self._CheckMods("disk", self.op.disks, {},
+                      self._VerifyDiskModification)
+    else:
+      self._CheckMods("disk", self.op.disks, constants.IDISK_PARAMS_TYPES,
+                      self._VerifyDiskModification)
 
-    if self.op.remote_node is not None:
-      self.op.remote_node = _ExpandNodeName(self.cfg, self.op.remote_node)
+    # Prepare disk/NIC modifications
+    self.diskmod = _PrepareContainerMods(self.op.disks, None)
+    self.nicmod = _PrepareContainerMods(self.op.nics, _InstNicModPrivate)
 
-      # Warning: do not remove the locking of the new secondary here
-      # unless DRBD8.AddChildren is changed to work in parallel;
-      # currently it doesn't since parallel invocations of
-      # FindUnusedMinor will conflict
-      self.needed_locks[locking.LEVEL_NODE] = [self.op.remote_node]
-      self.recalculate_locks[locking.LEVEL_NODE] = constants.LOCKS_APPEND
+    # Check the validity of the `provider' parameter
+    if instance.disk_template in constants.DT_EXT:
+      for mod in self.diskmod:
+        ext_provider = mod[2].get(constants.IDISK_PROVIDER, None)
+        if mod[0] == constants.DDM_ADD:
+          if ext_provider is None:
+            raise errors.OpPrereqError("Instance template is '%s' and parameter"
+                                       " '%s' missing, during disk add" %
+                                       (constants.DT_EXT,
+                                        constants.IDISK_PROVIDER),
+                                       errors.ECODE_NOENT)
+        elif mod[0] == constants.DDM_MODIFY:
+          if ext_provider:
+            raise errors.OpPrereqError("Parameter '%s' is invalid during disk"
+                                       " modification" %
+                                       constants.IDISK_PROVIDER,
+                                       errors.ECODE_INVAL)
     else:
-      self.needed_locks[locking.LEVEL_NODE] = []
-      self.recalculate_locks[locking.LEVEL_NODE] = constants.LOCKS_REPLACE
+      for mod in self.diskmod:
+        ext_provider = mod[2].get(constants.IDISK_PROVIDER, None)
+        if ext_provider is not None:
+          raise errors.OpPrereqError("Parameter '%s' is only valid for"
+                                     " instances of type '%s'" %
+                                     (constants.IDISK_PROVIDER,
+                                      constants.DT_EXT),
+                                     errors.ECODE_INVAL)
 
-      if self.op.iallocator is not None:
-        # iallocator will select a new node in the same group
-        self.needed_locks[locking.LEVEL_NODEGROUP] = []
-        self.needed_locks[locking.LEVEL_NODE_ALLOC] = locking.ALL_SET
-
-    self.needed_locks[locking.LEVEL_NODE_RES] = []
-
-    self.replacer = TLReplaceDisks(self, self.op.instance_name, self.op.mode,
-                                   self.op.iallocator, self.op.remote_node,
-                                   self.op.disks, self.op.early_release,
-                                   self.op.ignore_ipolicy)
-
-    self.tasklets = [self.replacer]
-
-  def DeclareLocks(self, level):
-    if level == locking.LEVEL_NODEGROUP:
-      assert self.op.remote_node is None
-      assert self.op.iallocator is not None
-      assert not self.needed_locks[locking.LEVEL_NODEGROUP]
-
-      self.share_locks[locking.LEVEL_NODEGROUP] = 1
-      # Lock all groups used by instance optimistically; this requires going
-      # via the node before it's locked, requiring verification later on
-      self.needed_locks[locking.LEVEL_NODEGROUP] = \
-        self.cfg.GetInstanceNodeGroups(self.op.instance_name)
-
-    elif level == locking.LEVEL_NODE:
-      if self.op.iallocator is not None:
-        assert self.op.remote_node is None
-        assert not self.needed_locks[locking.LEVEL_NODE]
-        assert locking.NAL in self.owned_locks(locking.LEVEL_NODE_ALLOC)
-
-        # Lock member nodes of all locked groups
-        self.needed_locks[locking.LEVEL_NODE] = \
-          [node_name
-           for group_uuid in self.owned_locks(locking.LEVEL_NODEGROUP)
-           for node_name in self.cfg.GetNodeGroup(group_uuid).members]
-      else:
-        assert not self.glm.is_owned(locking.LEVEL_NODE_ALLOC)
-
-        self._LockInstancesNodes()
-
-    elif level == locking.LEVEL_NODE_RES:
-      # Reuse node locks
-      self.needed_locks[locking.LEVEL_NODE_RES] = \
-        self.needed_locks[locking.LEVEL_NODE]
-
-  def BuildHooksEnv(self):
-    """Build hooks env.
-
-    This runs on the master, the primary and all the secondaries.
-
-    """
-    instance = self.replacer.instance
-    env = {
-      "MODE": self.op.mode,
-      "NEW_SECONDARY": self.op.remote_node,
-      "OLD_SECONDARY": instance.secondary_nodes[0],
-      }
-    env.update(_BuildInstanceHookEnvByObject(self, instance))
-    return env
-
-  def BuildHooksNodes(self):
-    """Build hooks nodes.
-
-    """
-    instance = self.replacer.instance
-    nl = [
-      self.cfg.GetMasterNode(),
-      instance.primary_node,
-      ]
-    if self.op.remote_node is not None:
-      nl.append(self.op.remote_node)
-    return nl, nl
-
-  def CheckPrereq(self):
-    """Check prerequisites.
-
-    """
-    assert (self.glm.is_owned(locking.LEVEL_NODEGROUP) or
-            self.op.iallocator is None)
-
-    # Verify if node group locks are still correct
-    owned_groups = self.owned_locks(locking.LEVEL_NODEGROUP)
-    if owned_groups:
-      _CheckInstanceNodeGroups(self.cfg, self.op.instance_name, owned_groups)
-
-    return LogicalUnit.CheckPrereq(self)
-
-
-class LUInstanceActivateDisks(NoHooksLU):
-  """Bring up an instance's disks.
-
-  """
-  REQ_BGL = False
-
-  def ExpandNames(self):
-    self._ExpandAndLockInstance()
-    self.needed_locks[locking.LEVEL_NODE] = []
-    self.recalculate_locks[locking.LEVEL_NODE] = constants.LOCKS_REPLACE
-
-  def DeclareLocks(self, level):
-    if level == locking.LEVEL_NODE:
-      self._LockInstancesNodes()
-
-  def CheckPrereq(self):
-    """Check prerequisites.
-
-    This checks that the instance is in the cluster.
-
-    """
-    self.instance = self.cfg.GetInstanceInfo(self.op.instance_name)
-    assert self.instance is not None, \
-      "Cannot retrieve locked instance %s" % self.op.instance_name
-    _CheckNodeOnline(self, self.instance.primary_node)
-
-  def Exec(self, feedback_fn):
-    """Activate the disks.
-
-    """
-    disks_ok, disks_info = \
-              _AssembleInstanceDisks(self, self.instance,
-                                     ignore_size=self.op.ignore_size)
-    if not disks_ok:
-      raise errors.OpExecError("Cannot activate block devices")
-
-    if self.op.wait_for_sync:
-      if not _WaitForSync(self, self.instance):
-        raise errors.OpExecError("Some disks of the instance are degraded!")
-
-    return disks_info
-
-
-class LUInstanceDeactivateDisks(NoHooksLU):
-  """Shutdown an instance's disks.
-
-  """
-  REQ_BGL = False
-
-  def ExpandNames(self):
-    self._ExpandAndLockInstance()
-    self.needed_locks[locking.LEVEL_NODE] = []
-    self.recalculate_locks[locking.LEVEL_NODE] = constants.LOCKS_REPLACE
-
-  def DeclareLocks(self, level):
-    if level == locking.LEVEL_NODE:
-      self._LockInstancesNodes()
-
-  def CheckPrereq(self):
-    """Check prerequisites.
-
-    This checks that the instance is in the cluster.
-
-    """
-    self.instance = self.cfg.GetInstanceInfo(self.op.instance_name)
-    assert self.instance is not None, \
-      "Cannot retrieve locked instance %s" % self.op.instance_name
-
-  def Exec(self, feedback_fn):
-    """Deactivate the disks
-
-    """
-    instance = self.instance
-    if self.op.force:
-      _ShutdownInstanceDisks(self, instance)
-    else:
-      _SafeShutdownInstanceDisks(self, instance)
-
-
-class LUInstanceStartup(LogicalUnit):
-  """Starts an instance.
-
-  """
-  HPATH = "instance-start"
-  HTYPE = constants.HTYPE_INSTANCE
-  REQ_BGL = False
-
-  def CheckArguments(self):
-    # extra beparams
-    if self.op.beparams:
-      # fill the beparams dict
-      objects.UpgradeBeParams(self.op.beparams)
-      utils.ForceDictType(self.op.beparams, constants.BES_PARAMETER_TYPES)
-
-  def ExpandNames(self):
-    self._ExpandAndLockInstance()
-    self.recalculate_locks[locking.LEVEL_NODE_RES] = constants.LOCKS_REPLACE
-
-  def DeclareLocks(self, level):
-    if level == locking.LEVEL_NODE_RES:
-      self._LockInstancesNodes(primary_only=True, level=locking.LEVEL_NODE_RES)
-
-  def BuildHooksEnv(self):
-    """Build hooks env.
-
-    This runs on master, primary and secondary nodes of the instance.
-
-    """
-    env = {
-      "FORCE": self.op.force,
-      }
-
-    env.update(_BuildInstanceHookEnvByObject(self, self.instance))
-
-    return env
-
-  def BuildHooksNodes(self):
-    """Build hooks nodes.
-
-    """
-    nl = [self.cfg.GetMasterNode()] + list(self.instance.all_nodes)
-    return (nl, nl)
-
-  def CheckPrereq(self):
-    """Check prerequisites.
-
-    This checks that the instance is in the cluster.
-
-    """
-    self.instance = instance = self.cfg.GetInstanceInfo(self.op.instance_name)
-    assert self.instance is not None, \
-      "Cannot retrieve locked instance %s" % self.op.instance_name
-
-    # extra hvparams
-    if self.op.hvparams:
-      # check hypervisor parameter syntax (locally)
-      cluster = self.cfg.GetClusterInfo()
-      utils.ForceDictType(self.op.hvparams, constants.HVS_PARAMETER_TYPES)
-      filled_hvp = cluster.FillHV(instance)
-      filled_hvp.update(self.op.hvparams)
-      hv_type = hypervisor.GetHypervisorClass(instance.hypervisor)
-      hv_type.CheckParameterSyntax(filled_hvp)
-      _CheckHVParams(self, instance.all_nodes, instance.hypervisor, filled_hvp)
-
-    _CheckInstanceState(self, instance, INSTANCE_ONLINE)
-
-    self.primary_offline = self.cfg.GetNodeInfo(instance.primary_node).offline
-
-    if self.primary_offline and self.op.ignore_offline_nodes:
-      self.LogWarning("Ignoring offline primary node")
-
-      if self.op.hvparams or self.op.beparams:
-        self.LogWarning("Overridden parameters are ignored")
-    else:
-      _CheckNodeOnline(self, instance.primary_node)
-
-      bep = self.cfg.GetClusterInfo().FillBE(instance)
-      bep.update(self.op.beparams)
-
-      # check bridges existence
-      _CheckInstanceBridgesExist(self, instance)
-
-      remote_info = self.rpc.call_instance_info(instance.primary_node,
-                                                instance.name,
-                                                instance.hypervisor)
-      remote_info.Raise("Error checking node %s" % instance.primary_node,
-                        prereq=True, ecode=errors.ECODE_ENVIRON)
-      if not remote_info.payload: # not running already
-        _CheckNodeFreeMemory(self, instance.primary_node,
-                             "starting instance %s" % instance.name,
-                             bep[constants.BE_MINMEM], instance.hypervisor)
-
-  def Exec(self, feedback_fn):
-    """Start the instance.
-
-    """
-    instance = self.instance
-    force = self.op.force
-    reason = self.op.reason
-
-    if not self.op.no_remember:
-      self.cfg.MarkInstanceUp(instance.name)
-
-    if self.primary_offline:
-      assert self.op.ignore_offline_nodes
-      self.LogInfo("Primary node offline, marked instance as started")
-    else:
-      node_current = instance.primary_node
-
-      _StartInstanceDisks(self, instance, force)
-
-      result = \
-        self.rpc.call_instance_start(node_current,
-                                     (instance, self.op.hvparams,
-                                      self.op.beparams),
-                                     self.op.startup_paused, reason)
-      msg = result.fail_msg
-      if msg:
-        _ShutdownInstanceDisks(self, instance)
-        raise errors.OpExecError("Could not start instance: %s" % msg)
-
-
-class LUInstanceShutdown(LogicalUnit):
-  """Shutdown an instance.
-
-  """
-  HPATH = "instance-stop"
-  HTYPE = constants.HTYPE_INSTANCE
-  REQ_BGL = False
-
-  def ExpandNames(self):
-    self._ExpandAndLockInstance()
-
-  def BuildHooksEnv(self):
-    """Build hooks env.
-
-    This runs on master, primary and secondary nodes of the instance.
-
-    """
-    env = _BuildInstanceHookEnvByObject(self, self.instance)
-    env["TIMEOUT"] = self.op.timeout
-    return env
-
-  def BuildHooksNodes(self):
-    """Build hooks nodes.
-
-    """
-    nl = [self.cfg.GetMasterNode()] + list(self.instance.all_nodes)
-    return (nl, nl)
-
-  def CheckPrereq(self):
-    """Check prerequisites.
-
-    This checks that the instance is in the cluster.
-
-    """
-    self.instance = self.cfg.GetInstanceInfo(self.op.instance_name)
-    assert self.instance is not None, \
-      "Cannot retrieve locked instance %s" % self.op.instance_name
-
-    if not self.op.force:
-      _CheckInstanceState(self, self.instance, INSTANCE_ONLINE)
-    else:
-      self.LogWarning("Ignoring offline instance check")
-
-    self.primary_offline = \
-      self.cfg.GetNodeInfo(self.instance.primary_node).offline
-
-    if self.primary_offline and self.op.ignore_offline_nodes:
-      self.LogWarning("Ignoring offline primary node")
-    else:
-      _CheckNodeOnline(self, self.instance.primary_node)
-
-  def Exec(self, feedback_fn):
-    """Shutdown the instance.
-
-    """
-    instance = self.instance
-    node_current = instance.primary_node
-    timeout = self.op.timeout
-    reason = self.op.reason
-
-    # If the instance is offline we shouldn't mark it as down, as that
-    # resets the offline flag.
-    if not self.op.no_remember and instance.admin_state in INSTANCE_ONLINE:
-      self.cfg.MarkInstanceDown(instance.name)
-
-    if self.primary_offline:
-      assert self.op.ignore_offline_nodes
-      self.LogInfo("Primary node offline, marked instance as stopped")
-    else:
-      result = self.rpc.call_instance_shutdown(node_current, instance, timeout,
-                                               reason)
-      msg = result.fail_msg
-      if msg:
-        self.LogWarning("Could not shutdown instance: %s", msg)
-
-      _ShutdownInstanceDisks(self, instance)
-
-
-class LUInstanceReinstall(LogicalUnit):
-  """Reinstall an instance.
-
-  """
-  HPATH = "instance-reinstall"
-  HTYPE = constants.HTYPE_INSTANCE
-  REQ_BGL = False
-
-  def ExpandNames(self):
-    self._ExpandAndLockInstance()
-
-  def BuildHooksEnv(self):
-    """Build hooks env.
-
-    This runs on master, primary and secondary nodes of the instance.
-
-    """
-    return _BuildInstanceHookEnvByObject(self, self.instance)
-
-  def BuildHooksNodes(self):
-    """Build hooks nodes.
-
-    """
-    nl = [self.cfg.GetMasterNode()] + list(self.instance.all_nodes)
-    return (nl, nl)
-
-  def CheckPrereq(self):
-    """Check prerequisites.
-
-    This checks that the instance is in the cluster and is not running.
-
-    """
-    instance = self.cfg.GetInstanceInfo(self.op.instance_name)
-    assert instance is not None, \
-      "Cannot retrieve locked instance %s" % self.op.instance_name
-    _CheckNodeOnline(self, instance.primary_node, "Instance primary node"
-                     " offline, cannot reinstall")
-
-    if instance.disk_template == constants.DT_DISKLESS:
-      raise errors.OpPrereqError("Instance '%s' has no disks" %
-                                 self.op.instance_name,
-                                 errors.ECODE_INVAL)
-    _CheckInstanceState(self, instance, INSTANCE_DOWN, msg="cannot reinstall")
-
-    if self.op.os_type is not None:
-      # OS verification
-      pnode = _ExpandNodeName(self.cfg, instance.primary_node)
-      _CheckNodeHasOS(self, pnode, self.op.os_type, self.op.force_variant)
-      instance_os = self.op.os_type
-    else:
-      instance_os = instance.os
-
-    nodelist = list(instance.all_nodes)
-
-    if self.op.osparams:
-      i_osdict = _GetUpdatedParams(instance.osparams, self.op.osparams)
-      _CheckOSParams(self, True, nodelist, instance_os, i_osdict)
-      self.os_inst = i_osdict # the new dict (without defaults)
-    else:
-      self.os_inst = None
-
-    self.instance = instance
-
-  def Exec(self, feedback_fn):
-    """Reinstall the instance.
-
-    """
-    inst = self.instance
-
-    if self.op.os_type is not None:
-      feedback_fn("Changing OS to '%s'..." % self.op.os_type)
-      inst.os = self.op.os_type
-      # Write to configuration
-      self.cfg.Update(inst, feedback_fn)
-
-    _StartInstanceDisks(self, inst, None)
-    try:
-      feedback_fn("Running the instance OS create scripts...")
-      # FIXME: pass debug option from opcode to backend
-      result = self.rpc.call_instance_os_add(inst.primary_node,
-                                             (inst, self.os_inst), True,
-                                             self.op.debug_level)
-      result.Raise("Could not install OS for instance %s on node %s" %
-                   (inst.name, inst.primary_node))
-    finally:
-      _ShutdownInstanceDisks(self, inst)
-
-
-class LUInstanceReboot(LogicalUnit):
-  """Reboot an instance.
-
-  """
-  HPATH = "instance-reboot"
-  HTYPE = constants.HTYPE_INSTANCE
-  REQ_BGL = False
-
-  def ExpandNames(self):
-    self._ExpandAndLockInstance()
-
-  def BuildHooksEnv(self):
-    """Build hooks env.
-
-    This runs on master, primary and secondary nodes of the instance.
-
-    """
-    env = {
-      "IGNORE_SECONDARIES": self.op.ignore_secondaries,
-      "REBOOT_TYPE": self.op.reboot_type,
-      "SHUTDOWN_TIMEOUT": self.op.shutdown_timeout,
-      }
-
-    env.update(_BuildInstanceHookEnvByObject(self, self.instance))
-
-    return env
-
-  def BuildHooksNodes(self):
-    """Build hooks nodes.
-
-    """
-    nl = [self.cfg.GetMasterNode()] + list(self.instance.all_nodes)
-    return (nl, nl)
-
-  def CheckPrereq(self):
-    """Check prerequisites.
-
-    This checks that the instance is in the cluster.
-
-    """
-    self.instance = instance = self.cfg.GetInstanceInfo(self.op.instance_name)
-    assert self.instance is not None, \
-      "Cannot retrieve locked instance %s" % self.op.instance_name
-    _CheckInstanceState(self, instance, INSTANCE_ONLINE)
-    _CheckNodeOnline(self, instance.primary_node)
-
-    # check bridges existence
-    _CheckInstanceBridgesExist(self, instance)
-
-  def Exec(self, feedback_fn):
-    """Reboot the instance.
-
-    """
-    instance = self.instance
-    ignore_secondaries = self.op.ignore_secondaries
-    reboot_type = self.op.reboot_type
-    reason = self.op.reason
-
-    remote_info = self.rpc.call_instance_info(instance.primary_node,
-                                              instance.name,
-                                              instance.hypervisor)
-    remote_info.Raise("Error checking node %s" % instance.primary_node)
-    instance_running = bool(remote_info.payload)
-
-    node_current = instance.primary_node
-
-    if instance_running and reboot_type in [constants.INSTANCE_REBOOT_SOFT,
-                                            constants.INSTANCE_REBOOT_HARD]:
-      for disk in instance.disks:
-        self.cfg.SetDiskID(disk, node_current)
-      result = self.rpc.call_instance_reboot(node_current, instance,
-                                             reboot_type,
-                                             self.op.shutdown_timeout, reason)
-      result.Raise("Could not reboot instance")
-    else:
-      if instance_running:
-        result = self.rpc.call_instance_shutdown(node_current, instance,
-                                                 self.op.shutdown_timeout,
-                                                 reason)
-        result.Raise("Could not shutdown instance for full reboot")
-        _ShutdownInstanceDisks(self, instance)
-      else:
-        self.LogInfo("Instance %s was already stopped, starting now",
-                     instance.name)
-      _StartInstanceDisks(self, instance, ignore_secondaries)
-      result = self.rpc.call_instance_start(node_current,
-                                            (instance, None, None), False,
-                                            reason)
-      msg = result.fail_msg
-      if msg:
-        _ShutdownInstanceDisks(self, instance)
-        raise errors.OpExecError("Could not start instance for"
-                                 " full reboot: %s" % msg)
-
-    self.cfg.MarkInstanceUp(instance.name)
-
-
-class LUInstanceConsole(NoHooksLU):
-  """Connect to an instance's console.
-
-  This is somewhat special in that it returns the command line that
-  you need to run on the master node in order to connect to the
-  console.
-
-  """
-  REQ_BGL = False
-
-  def ExpandNames(self):
-    self.share_locks = _ShareAll()
-    self._ExpandAndLockInstance()
-
-  def CheckPrereq(self):
-    """Check prerequisites.
-
-    This checks that the instance is in the cluster.
-
-    """
-    self.instance = self.cfg.GetInstanceInfo(self.op.instance_name)
-    assert self.instance is not None, \
-      "Cannot retrieve locked instance %s" % self.op.instance_name
-    _CheckNodeOnline(self, self.instance.primary_node)
-
-  def Exec(self, feedback_fn):
-    """Connect to the console of an instance
-
-    """
-    instance = self.instance
-    node = instance.primary_node
-
-    node_insts = self.rpc.call_instance_list([node],
-                                             [instance.hypervisor])[node]
-    node_insts.Raise("Can't get node information from %s" % node)
-
-    if instance.name not in node_insts.payload:
-      if instance.admin_state == constants.ADMINST_UP:
-        state = constants.INSTST_ERRORDOWN
-      elif instance.admin_state == constants.ADMINST_DOWN:
-        state = constants.INSTST_ADMINDOWN
-      else:
-        state = constants.INSTST_ADMINOFFLINE
-      raise errors.OpExecError("Instance %s is not running (state %s)" %
-                               (instance.name, state))
-
-    logging.debug("Connecting to console of %s on %s", instance.name, node)
-
-    return _GetInstanceConsole(self.cfg.GetClusterInfo(), instance)
-
-
-def _DeclareLocksForMigration(lu, level):
-  """Declares locks for L{TLMigrateInstance}.
-
-  @type lu: L{LogicalUnit}
-  @param level: Lock level
-
-  """
-  if level == locking.LEVEL_NODE_ALLOC:
-    assert lu.op.instance_name in lu.owned_locks(locking.LEVEL_INSTANCE)
-
-    instance = lu.cfg.GetInstanceInfo(lu.op.instance_name)
-
-    # Node locks are already declared here rather than at LEVEL_NODE as we need
-    # the instance object anyway to declare the node allocation lock.
-    if instance.disk_template in constants.DTS_EXT_MIRROR:
-      if lu.op.target_node is None:
-        lu.needed_locks[locking.LEVEL_NODE] = locking.ALL_SET
-        lu.needed_locks[locking.LEVEL_NODE_ALLOC] = locking.ALL_SET
-      else:
-        lu.needed_locks[locking.LEVEL_NODE] = [instance.primary_node,
-                                               lu.op.target_node]
-      del lu.recalculate_locks[locking.LEVEL_NODE]
-    else:
-      lu._LockInstancesNodes() # pylint: disable=W0212
-
-  elif level == locking.LEVEL_NODE:
-    # Node locks are declared together with the node allocation lock
-    assert (lu.needed_locks[locking.LEVEL_NODE] or
-            lu.needed_locks[locking.LEVEL_NODE] is locking.ALL_SET)
-
-  elif level == locking.LEVEL_NODE_RES:
-    # Copy node locks
-    lu.needed_locks[locking.LEVEL_NODE_RES] = \
-      _CopyLockList(lu.needed_locks[locking.LEVEL_NODE])
-
-
-def _ExpandNamesForMigration(lu):
-  """Expands names for use with L{TLMigrateInstance}.
-
-  @type lu: L{LogicalUnit}
-
-  """
-  if lu.op.target_node is not None:
-    lu.op.target_node = _ExpandNodeName(lu.cfg, lu.op.target_node)
-
-  lu.needed_locks[locking.LEVEL_NODE] = []
-  lu.recalculate_locks[locking.LEVEL_NODE] = constants.LOCKS_REPLACE
-
-  lu.needed_locks[locking.LEVEL_NODE_RES] = []
-  lu.recalculate_locks[locking.LEVEL_NODE_RES] = constants.LOCKS_REPLACE
-
-  # The node allocation lock is actually only needed for externally replicated
-  # instances (e.g. sharedfile or RBD) and if an iallocator is used.
-  lu.needed_locks[locking.LEVEL_NODE_ALLOC] = []
-
-
-class LUInstanceFailover(LogicalUnit):
-  """Failover an instance.
-
-  """
-  HPATH = "instance-failover"
-  HTYPE = constants.HTYPE_INSTANCE
-  REQ_BGL = False
-
-  def CheckArguments(self):
-    """Check the arguments.
-
-    """
-    self.iallocator = getattr(self.op, "iallocator", None)
-    self.target_node = getattr(self.op, "target_node", None)
-
-  def ExpandNames(self):
-    self._ExpandAndLockInstance()
-    _ExpandNamesForMigration(self)
-
-    self._migrater = \
-      TLMigrateInstance(self, self.op.instance_name, False, True, False,
-                        self.op.ignore_consistency, True,
-                        self.op.shutdown_timeout, self.op.ignore_ipolicy)
-
-    self.tasklets = [self._migrater]
-
-  def DeclareLocks(self, level):
-    _DeclareLocksForMigration(self, level)
-
-  def BuildHooksEnv(self):
-    """Build hooks env.
-
-    This runs on master, primary and secondary nodes of the instance.
-
-    """
-    instance = self._migrater.instance
-    source_node = instance.primary_node
-    target_node = self.op.target_node
-    env = {
-      "IGNORE_CONSISTENCY": self.op.ignore_consistency,
-      "SHUTDOWN_TIMEOUT": self.op.shutdown_timeout,
-      "OLD_PRIMARY": source_node,
-      "NEW_PRIMARY": target_node,
-      }
-
-    if instance.disk_template in constants.DTS_INT_MIRROR:
-      env["OLD_SECONDARY"] = instance.secondary_nodes[0]
-      env["NEW_SECONDARY"] = source_node
-    else:
-      env["OLD_SECONDARY"] = env["NEW_SECONDARY"] = ""
-
-    env.update(_BuildInstanceHookEnvByObject(self, instance))
-
-    return env
-
-  def BuildHooksNodes(self):
-    """Build hooks nodes.
-
-    """
-    instance = self._migrater.instance
-    nl = [self.cfg.GetMasterNode()] + list(instance.secondary_nodes)
-    return (nl, nl + [instance.primary_node])
-
-
-class LUInstanceMigrate(LogicalUnit):
-  """Migrate an instance.
-
-  This is migration without shutting down, compared to the failover,
-  which is done with shutdown.
-
-  """
-  HPATH = "instance-migrate"
-  HTYPE = constants.HTYPE_INSTANCE
-  REQ_BGL = False
-
-  def ExpandNames(self):
-    self._ExpandAndLockInstance()
-    _ExpandNamesForMigration(self)
-
-    self._migrater = \
-      TLMigrateInstance(self, self.op.instance_name, self.op.cleanup,
-                        False, self.op.allow_failover, False,
-                        self.op.allow_runtime_changes,
-                        constants.DEFAULT_SHUTDOWN_TIMEOUT,
-                        self.op.ignore_ipolicy)
-
-    self.tasklets = [self._migrater]
-
-  def DeclareLocks(self, level):
-    _DeclareLocksForMigration(self, level)
-
-  def BuildHooksEnv(self):
-    """Build hooks env.
-
-    This runs on master, primary and secondary nodes of the instance.
-
-    """
-    instance = self._migrater.instance
-    source_node = instance.primary_node
-    target_node = self.op.target_node
-    env = _BuildInstanceHookEnvByObject(self, instance)
-    env.update({
-      "MIGRATE_LIVE": self._migrater.live,
-      "MIGRATE_CLEANUP": self.op.cleanup,
-      "OLD_PRIMARY": source_node,
-      "NEW_PRIMARY": target_node,
-      "ALLOW_RUNTIME_CHANGES": self.op.allow_runtime_changes,
-      })
-
-    if instance.disk_template in constants.DTS_INT_MIRROR:
-      env["OLD_SECONDARY"] = target_node
-      env["NEW_SECONDARY"] = source_node
-    else:
-      env["OLD_SECONDARY"] = env["NEW_SECONDARY"] = None
-
-    return env
-
-  def BuildHooksNodes(self):
-    """Build hooks nodes.
-
-    """
-    instance = self._migrater.instance
-    snodes = list(instance.secondary_nodes)
-    nl = [self.cfg.GetMasterNode(), instance.primary_node] + snodes
-    return (nl, nl)
-
-
-class LUInstanceMultiAlloc(NoHooksLU):
-  """Allocates multiple instances at the same time.
-
-  """
-  REQ_BGL = False
-
-  def CheckArguments(self):
-    """Check arguments.
-
-    """
-    nodes = []
-    for inst in self.op.instances:
-      if inst.iallocator is not None:
-        raise errors.OpPrereqError("iallocator are not allowed to be set on"
-                                   " instance objects", errors.ECODE_INVAL)
-      nodes.append(bool(inst.pnode))
-      if inst.disk_template in constants.DTS_INT_MIRROR:
-        nodes.append(bool(inst.snode))
-
-    has_nodes = compat.any(nodes)
-    if compat.all(nodes) ^ has_nodes:
-      raise errors.OpPrereqError("There are instance objects providing"
-                                 " pnode/snode while others do not",
-                                 errors.ECODE_INVAL)
-
-    if self.op.iallocator is None:
-      default_iallocator = self.cfg.GetDefaultIAllocator()
-      if default_iallocator and has_nodes:
-        self.op.iallocator = default_iallocator
-      else:
-        raise errors.OpPrereqError("No iallocator or nodes on the instances"
-                                   " given and no cluster-wide default"
-                                   " iallocator found; please specify either"
-                                   " an iallocator or nodes on the instances"
-                                   " or set a cluster-wide default iallocator",
-                                   errors.ECODE_INVAL)
-
-    _CheckOpportunisticLocking(self.op)
-
-    dups = utils.FindDuplicates([op.instance_name for op in self.op.instances])
-    if dups:
-      raise errors.OpPrereqError("There are duplicate instance names: %s" %
-                                 utils.CommaJoin(dups), errors.ECODE_INVAL)
-
-  def ExpandNames(self):
-    """Calculate the locks.
-
-    """
-    self.share_locks = _ShareAll()
-    self.needed_locks = {
-      # iallocator will select nodes and even if no iallocator is used,
-      # collisions with LUInstanceCreate should be avoided
-      locking.LEVEL_NODE_ALLOC: locking.ALL_SET,
-      }
-
-    if self.op.iallocator:
-      self.needed_locks[locking.LEVEL_NODE] = locking.ALL_SET
-      self.needed_locks[locking.LEVEL_NODE_RES] = locking.ALL_SET
-
-      if self.op.opportunistic_locking:
-        self.opportunistic_locks[locking.LEVEL_NODE] = True
-        self.opportunistic_locks[locking.LEVEL_NODE_RES] = True
-    else:
-      nodeslist = []
-      for inst in self.op.instances:
-        inst.pnode = _ExpandNodeName(self.cfg, inst.pnode)
-        nodeslist.append(inst.pnode)
-        if inst.snode is not None:
-          inst.snode = _ExpandNodeName(self.cfg, inst.snode)
-          nodeslist.append(inst.snode)
-
-      self.needed_locks[locking.LEVEL_NODE] = nodeslist
-      # Lock resources of instance's primary and secondary nodes (copy to
-      # prevent accidential modification)
-      self.needed_locks[locking.LEVEL_NODE_RES] = list(nodeslist)
-
-  def CheckPrereq(self):
-    """Check prerequisite.
-
-    """
-    cluster = self.cfg.GetClusterInfo()
-    default_vg = self.cfg.GetVGName()
-    ec_id = self.proc.GetECId()
-
-    if self.op.opportunistic_locking:
-      # Only consider nodes for which a lock is held
-      node_whitelist = list(self.owned_locks(locking.LEVEL_NODE))
-    else:
-      node_whitelist = None
-
-    insts = [_CreateInstanceAllocRequest(op, _ComputeDisks(op, default_vg),
-                                         _ComputeNics(op, cluster, None,
-                                                      self.cfg, ec_id),
-                                         _ComputeFullBeParams(op, cluster),
-                                         node_whitelist)
-             for op in self.op.instances]
-
-    req = iallocator.IAReqMultiInstanceAlloc(instances=insts)
-    ial = iallocator.IAllocator(self.cfg, self.rpc, req)
-
-    ial.Run(self.op.iallocator)
-
-    if not ial.success:
-      raise errors.OpPrereqError("Can't compute nodes using"
-                                 " iallocator '%s': %s" %
-                                 (self.op.iallocator, ial.info),
-                                 errors.ECODE_NORES)
-
-    self.ia_result = ial.result
-
-    if self.op.dry_run:
-      self.dry_run_result = objects.FillDict(self._ConstructPartialResult(), {
-        constants.JOB_IDS_KEY: [],
-        })
-
-  def _ConstructPartialResult(self):
-    """Contructs the partial result.
-
-    """
-    (allocatable, failed) = self.ia_result
-    return {
-      opcodes.OpInstanceMultiAlloc.ALLOCATABLE_KEY:
-        map(compat.fst, allocatable),
-      opcodes.OpInstanceMultiAlloc.FAILED_KEY: failed,
-      }
-
-  def Exec(self, feedback_fn):
-    """Executes the opcode.
-
-    """
-    op2inst = dict((op.instance_name, op) for op in self.op.instances)
-    (allocatable, failed) = self.ia_result
-
-    jobs = []
-    for (name, nodes) in allocatable:
-      op = op2inst.pop(name)
-
-      if len(nodes) > 1:
-        (op.pnode, op.snode) = nodes
-      else:
-        (op.pnode,) = nodes
-
-      jobs.append([op])
-
-    missing = set(op2inst.keys()) - set(failed)
-    assert not missing, \
-      "Iallocator did return incomplete result: %s" % utils.CommaJoin(missing)
-
-    return ResultWithJobs(jobs, **self._ConstructPartialResult())
-
-
-class _InstNicModPrivate:
-  """Data structure for network interface modifications.
-
-  Used by L{LUInstanceSetParams}.
-
-  """
-  def __init__(self):
-    self.params = None
-    self.filled = None
-
-
-def PrepareContainerMods(mods, private_fn):
-  """Prepares a list of container modifications by adding a private data field.
-
-  @type mods: list of tuples; (operation, index, parameters)
-  @param mods: List of modifications
-  @type private_fn: callable or None
-  @param private_fn: Callable for constructing a private data field for a
-    modification
-  @rtype: list
-
-  """
-  if private_fn is None:
-    fn = lambda: None
-  else:
-    fn = private_fn
-
-  return [(op, idx, params, fn()) for (op, idx, params) in mods]
-
-
-def _CheckNodesPhysicalCPUs(lu, nodenames, requested, hypervisor_name):
-  """Checks if nodes have enough physical CPUs
-
-  This function checks if all given nodes have the needed number of
-  physical CPUs. In case any node has less CPUs or we cannot get the
-  information from the node, this function raises an OpPrereqError
-  exception.
-
-  @type lu: C{LogicalUnit}
-  @param lu: a logical unit from which we get configuration data
-  @type nodenames: C{list}
-  @param nodenames: the list of node names to check
-  @type requested: C{int}
-  @param requested: the minimum acceptable number of physical CPUs
-  @raise errors.OpPrereqError: if the node doesn't have enough CPUs,
-      or we cannot check the node
-
-  """
-  nodeinfo = lu.rpc.call_node_info(nodenames, None, [hypervisor_name], None)
-  for node in nodenames:
-    info = nodeinfo[node]
-    info.Raise("Cannot get current information from node %s" % node,
-               prereq=True, ecode=errors.ECODE_ENVIRON)
-    (_, _, (hv_info, )) = info.payload
-    num_cpus = hv_info.get("cpu_total", None)
-    if not isinstance(num_cpus, int):
-      raise errors.OpPrereqError("Can't compute the number of physical CPUs"
-                                 " on node %s, result was '%s'" %
-                                 (node, num_cpus), errors.ECODE_ENVIRON)
-    if requested > num_cpus:
-      raise errors.OpPrereqError("Node %s has %s physical CPUs, but %s are "
-                                 "required" % (node, num_cpus, requested),
-                                 errors.ECODE_NORES)
-
-
-def GetItemFromContainer(identifier, kind, container):
-  """Return the item refered by the identifier.
-
-  @type identifier: string
-  @param identifier: Item index or name or UUID
-  @type kind: string
-  @param kind: One-word item description
-  @type container: list
-  @param container: Container to get the item from
-
-  """
-  # Index
-  try:
-    idx = int(identifier)
-    if idx == -1:
-      # Append
-      absidx = len(container) - 1
-    elif idx < 0:
-      raise IndexError("Not accepting negative indices other than -1")
-    elif idx > len(container):
-      raise IndexError("Got %s index %s, but there are only %s" %
-                       (kind, idx, len(container)))
-    else:
-      absidx = idx
-    return (absidx, container[idx])
-  except ValueError:
-    pass
-
-  for idx, item in enumerate(container):
-    if item.uuid == identifier or item.name == identifier:
-      return (idx, item)
-
-  raise errors.OpPrereqError("Cannot find %s with identifier %s" %
-                             (kind, identifier), errors.ECODE_NOENT)
-
-
-def ApplyContainerMods(kind, container, chgdesc, mods,
-                       create_fn, modify_fn, remove_fn):
-  """Applies descriptions in C{mods} to C{container}.
-
-  @type kind: string
-  @param kind: One-word item description
-  @type container: list
-  @param container: Container to modify
-  @type chgdesc: None or list
-  @param chgdesc: List of applied changes
-  @type mods: list
-  @param mods: Modifications as returned by L{PrepareContainerMods}
-  @type create_fn: callable
-  @param create_fn: Callback for creating a new item (L{constants.DDM_ADD});
-    receives absolute item index, parameters and private data object as added
-    by L{PrepareContainerMods}, returns tuple containing new item and changes
-    as list
-  @type modify_fn: callable
-  @param modify_fn: Callback for modifying an existing item
-    (L{constants.DDM_MODIFY}); receives absolute item index, item, parameters
-    and private data object as added by L{PrepareContainerMods}, returns
-    changes as list
-  @type remove_fn: callable
-  @param remove_fn: Callback on removing item; receives absolute item index,
-    item and private data object as added by L{PrepareContainerMods}
-
-  """
-  for (op, identifier, params, private) in mods:
-    changes = None
-
-    if op == constants.DDM_ADD:
-      # Calculate where item will be added
-      # When adding an item, identifier can only be an index
-      try:
-        idx = int(identifier)
-      except ValueError:
-        raise errors.OpPrereqError("Only possitive integer or -1 is accepted as"
-                                   " identifier for %s" % constants.DDM_ADD,
-                                   errors.ECODE_INVAL)
-      if idx == -1:
-        addidx = len(container)
-      else:
-        if idx < 0:
-          raise IndexError("Not accepting negative indices other than -1")
-        elif idx > len(container):
-          raise IndexError("Got %s index %s, but there are only %s" %
-                           (kind, idx, len(container)))
-        addidx = idx
-
-      if create_fn is None:
-        item = params
-      else:
-        (item, changes) = create_fn(addidx, params, private)
-
-      if idx == -1:
-        container.append(item)
-      else:
-        assert idx >= 0
-        assert idx <= len(container)
-        # list.insert does so before the specified index
-        container.insert(idx, item)
-    else:
-      # Retrieve existing item
-      (absidx, item) = GetItemFromContainer(identifier, kind, container)
-
-      if op == constants.DDM_REMOVE:
-        assert not params
-
-        if remove_fn is not None:
-          remove_fn(absidx, item, private)
-
-        changes = [("%s/%s" % (kind, absidx), "remove")]
-
-        assert container[absidx] == item
-        del container[absidx]
-      elif op == constants.DDM_MODIFY:
-        if modify_fn is not None:
-          changes = modify_fn(absidx, item, params, private)
-      else:
-        raise errors.ProgrammerError("Unhandled operation '%s'" % op)
-
-    assert _TApplyContModsCbChanges(changes)
-
-    if not (chgdesc is None or changes is None):
-      chgdesc.extend(changes)
-
-
-def _UpdateIvNames(base_index, disks):
-  """Updates the C{iv_name} attribute of disks.
-
-  @type disks: list of L{objects.Disk}
-
-  """
-  for (idx, disk) in enumerate(disks):
-    disk.iv_name = "disk/%s" % (base_index + idx, )
-
-
-class LUInstanceSetParams(LogicalUnit):
-  """Modifies an instances's parameters.
-
-  """
-  HPATH = "instance-modify"
-  HTYPE = constants.HTYPE_INSTANCE
-  REQ_BGL = False
-
-  @staticmethod
-  def _UpgradeDiskNicMods(kind, mods, verify_fn):
-    assert ht.TList(mods)
-    assert not mods or len(mods[0]) in (2, 3)
-
-    if mods and len(mods[0]) == 2:
-      result = []
-
-      addremove = 0
-      for op, params in mods:
-        if op in (constants.DDM_ADD, constants.DDM_REMOVE):
-          result.append((op, -1, params))
-          addremove += 1
-
-          if addremove > 1:
-            raise errors.OpPrereqError("Only one %s add or remove operation is"
-                                       " supported at a time" % kind,
-                                       errors.ECODE_INVAL)
-        else:
-          result.append((constants.DDM_MODIFY, op, params))
-
-      assert verify_fn(result)
-    else:
-      result = mods
-
-    return result
-
-  @staticmethod
-  def _CheckMods(kind, mods, key_types, item_fn):
-    """Ensures requested disk/NIC modifications are valid.
-
-    """
-    for (op, _, params) in mods:
-      assert ht.TDict(params)
-
-      # If 'key_types' is an empty dict, we assume we have an
-      # 'ext' template and thus do not ForceDictType
-      if key_types:
-        utils.ForceDictType(params, key_types)
-
-      if op == constants.DDM_REMOVE:
-        if params:
-          raise errors.OpPrereqError("No settings should be passed when"
-                                     " removing a %s" % kind,
-                                     errors.ECODE_INVAL)
-      elif op in (constants.DDM_ADD, constants.DDM_MODIFY):
-        item_fn(op, params)
-      else:
-        raise errors.ProgrammerError("Unhandled operation '%s'" % op)
-
-  @staticmethod
-  def _VerifyDiskModification(op, params):
-    """Verifies a disk modification.
-
-    """
-    if op == constants.DDM_ADD:
-      mode = params.setdefault(constants.IDISK_MODE, constants.DISK_RDWR)
-      if mode not in constants.DISK_ACCESS_SET:
-        raise errors.OpPrereqError("Invalid disk access mode '%s'" % mode,
-                                   errors.ECODE_INVAL)
-
-      size = params.get(constants.IDISK_SIZE, None)
-      if size is None:
-        raise errors.OpPrereqError("Required disk parameter '%s' missing" %
-                                   constants.IDISK_SIZE, errors.ECODE_INVAL)
-
-      try:
-        size = int(size)
-      except (TypeError, ValueError), err:
-        raise errors.OpPrereqError("Invalid disk size parameter: %s" % err,
-                                   errors.ECODE_INVAL)
-
-      params[constants.IDISK_SIZE] = size
-      name = params.get(constants.IDISK_NAME, None)
-      if name is not None and name.lower() == constants.VALUE_NONE:
-        params[constants.IDISK_NAME] = None
-
-    elif op == constants.DDM_MODIFY:
-      if constants.IDISK_SIZE in params:
-        raise errors.OpPrereqError("Disk size change not possible, use"
-                                   " grow-disk", errors.ECODE_INVAL)
-      if len(params) > 2:
-        raise errors.OpPrereqError("Disk modification doesn't support"
-                                   " additional arbitrary parameters",
-                                   errors.ECODE_INVAL)
-      name = params.get(constants.IDISK_NAME, None)
-      if name is not None and name.lower() == constants.VALUE_NONE:
-        params[constants.IDISK_NAME] = None
-
-  @staticmethod
-  def _VerifyNicModification(op, params):
-    """Verifies a network interface modification.
-
-    """
-    if op in (constants.DDM_ADD, constants.DDM_MODIFY):
-      ip = params.get(constants.INIC_IP, None)
-      name = params.get(constants.INIC_NAME, None)
-      req_net = params.get(constants.INIC_NETWORK, None)
-      link = params.get(constants.NIC_LINK, None)
-      mode = params.get(constants.NIC_MODE, None)
-      if name is not None and name.lower() == constants.VALUE_NONE:
-        params[constants.INIC_NAME] = None
-      if req_net is not None:
-        if req_net.lower() == constants.VALUE_NONE:
-          params[constants.INIC_NETWORK] = None
-          req_net = None
-        elif link is not None or mode is not None:
-          raise errors.OpPrereqError("If network is given"
-                                     " mode or link should not",
-                                     errors.ECODE_INVAL)
-
-      if op == constants.DDM_ADD:
-        macaddr = params.get(constants.INIC_MAC, None)
-        if macaddr is None:
-          params[constants.INIC_MAC] = constants.VALUE_AUTO
-
-      if ip is not None:
-        if ip.lower() == constants.VALUE_NONE:
-          params[constants.INIC_IP] = None
-        else:
-          if ip.lower() == constants.NIC_IP_POOL:
-            if op == constants.DDM_ADD and req_net is None:
-              raise errors.OpPrereqError("If ip=pool, parameter network"
-                                         " cannot be none",
-                                         errors.ECODE_INVAL)
-          else:
-            if not netutils.IPAddress.IsValid(ip):
-              raise errors.OpPrereqError("Invalid IP address '%s'" % ip,
-                                         errors.ECODE_INVAL)
-
-      if constants.INIC_MAC in params:
-        macaddr = params[constants.INIC_MAC]
-        if macaddr not in (constants.VALUE_AUTO, constants.VALUE_GENERATE):
-          macaddr = utils.NormalizeAndValidateMac(macaddr)
-
-        if op == constants.DDM_MODIFY and macaddr == constants.VALUE_AUTO:
-          raise errors.OpPrereqError("'auto' is not a valid MAC address when"
-                                     " modifying an existing NIC",
-                                     errors.ECODE_INVAL)
-
-  def CheckArguments(self):
-    if not (self.op.nics or self.op.disks or self.op.disk_template or
-            self.op.hvparams or self.op.beparams or self.op.os_name or
-            self.op.offline is not None or self.op.runtime_mem or
-            self.op.pnode):
-      raise errors.OpPrereqError("No changes submitted", errors.ECODE_INVAL)
-
-    if self.op.hvparams:
-      _CheckParamsNotGlobal(self.op.hvparams, constants.HVC_GLOBALS,
-                            "hypervisor", "instance", "cluster")
-
-    self.op.disks = self._UpgradeDiskNicMods(
-      "disk", self.op.disks, opcodes.OpInstanceSetParams.TestDiskModifications)
-    self.op.nics = self._UpgradeDiskNicMods(
-      "NIC", self.op.nics, opcodes.OpInstanceSetParams.TestNicModifications)
-
-    if self.op.disks and self.op.disk_template is not None:
-      raise errors.OpPrereqError("Disk template conversion and other disk"
-                                 " changes not supported at the same time",
-                                 errors.ECODE_INVAL)
-
-    if (self.op.disk_template and
-        self.op.disk_template in constants.DTS_INT_MIRROR and
-        self.op.remote_node is None):
-      raise errors.OpPrereqError("Changing the disk template to a mirrored"
-                                 " one requires specifying a secondary node",
-                                 errors.ECODE_INVAL)
-
-    # Check NIC modifications
-    self._CheckMods("NIC", self.op.nics, constants.INIC_PARAMS_TYPES,
-                    self._VerifyNicModification)
-
-    if self.op.pnode:
-      self.op.pnode = _ExpandNodeName(self.cfg, self.op.pnode)
-
-  def ExpandNames(self):
-    self._ExpandAndLockInstance()
-    self.needed_locks[locking.LEVEL_NODEGROUP] = []
-    # Can't even acquire node locks in shared mode as upcoming changes in
-    # Ganeti 2.6 will start to modify the node object on disk conversion
-    self.needed_locks[locking.LEVEL_NODE] = []
-    self.needed_locks[locking.LEVEL_NODE_RES] = []
-    self.recalculate_locks[locking.LEVEL_NODE] = constants.LOCKS_REPLACE
-    # Look node group to look up the ipolicy
-    self.share_locks[locking.LEVEL_NODEGROUP] = 1
-
-  def DeclareLocks(self, level):
-    if level == locking.LEVEL_NODEGROUP:
-      assert not self.needed_locks[locking.LEVEL_NODEGROUP]
-      # Acquire locks for the instance's nodegroups optimistically. Needs
-      # to be verified in CheckPrereq
-      self.needed_locks[locking.LEVEL_NODEGROUP] = \
-        self.cfg.GetInstanceNodeGroups(self.op.instance_name)
-    elif level == locking.LEVEL_NODE:
-      self._LockInstancesNodes()
-      if self.op.disk_template and self.op.remote_node:
-        self.op.remote_node = _ExpandNodeName(self.cfg, self.op.remote_node)
-        self.needed_locks[locking.LEVEL_NODE].append(self.op.remote_node)
-    elif level == locking.LEVEL_NODE_RES and self.op.disk_template:
-      # Copy node locks
-      self.needed_locks[locking.LEVEL_NODE_RES] = \
-        _CopyLockList(self.needed_locks[locking.LEVEL_NODE])
-
-  def BuildHooksEnv(self):
-    """Build hooks env.
-
-    This runs on the master, primary and secondaries.
-
-    """
-    args = {}
-    if constants.BE_MINMEM in self.be_new:
-      args["minmem"] = self.be_new[constants.BE_MINMEM]
-    if constants.BE_MAXMEM in self.be_new:
-      args["maxmem"] = self.be_new[constants.BE_MAXMEM]
-    if constants.BE_VCPUS in self.be_new:
-      args["vcpus"] = self.be_new[constants.BE_VCPUS]
-    # TODO: export disk changes. Note: _BuildInstanceHookEnv* don't export disk
-    # information at all.
-
-    if self._new_nics is not None:
-      nics = []
-
-      for nic in self._new_nics:
-        n = copy.deepcopy(nic)
-        nicparams = self.cluster.SimpleFillNIC(n.nicparams)
-        n.nicparams = nicparams
-        nics.append(_NICToTuple(self, n))
-
-      args["nics"] = nics
-
-    env = _BuildInstanceHookEnvByObject(self, self.instance, override=args)
-    if self.op.disk_template:
-      env["NEW_DISK_TEMPLATE"] = self.op.disk_template
-    if self.op.runtime_mem:
-      env["RUNTIME_MEMORY"] = self.op.runtime_mem
-
-    return env
-
-  def BuildHooksNodes(self):
-    """Build hooks nodes.
-
-    """
-    nl = [self.cfg.GetMasterNode()] + list(self.instance.all_nodes)
-    return (nl, nl)
-
-  def _PrepareNicModification(self, params, private, old_ip, old_net_uuid,
-                              old_params, cluster, pnode):
-
-    update_params_dict = dict([(key, params[key])
-                               for key in constants.NICS_PARAMETERS
-                               if key in params])
-
-    req_link = update_params_dict.get(constants.NIC_LINK, None)
-    req_mode = update_params_dict.get(constants.NIC_MODE, None)
-
-    new_net_uuid = None
-    new_net_uuid_or_name = params.get(constants.INIC_NETWORK, old_net_uuid)
-    if new_net_uuid_or_name:
-      new_net_uuid = self.cfg.LookupNetwork(new_net_uuid_or_name)
-      new_net_obj = self.cfg.GetNetwork(new_net_uuid)
-
-    if old_net_uuid:
-      old_net_obj = self.cfg.GetNetwork(old_net_uuid)
-
-    if new_net_uuid:
-      netparams = self.cfg.GetGroupNetParams(new_net_uuid, pnode)
-      if not netparams:
-        raise errors.OpPrereqError("No netparams found for the network"
-                                   " %s, probably not connected" %
-                                   new_net_obj.name, errors.ECODE_INVAL)
-      new_params = dict(netparams)
-    else:
-      new_params = _GetUpdatedParams(old_params, update_params_dict)
-
-    utils.ForceDictType(new_params, constants.NICS_PARAMETER_TYPES)
-
-    new_filled_params = cluster.SimpleFillNIC(new_params)
-    objects.NIC.CheckParameterSyntax(new_filled_params)
-
-    new_mode = new_filled_params[constants.NIC_MODE]
-    if new_mode == constants.NIC_MODE_BRIDGED:
-      bridge = new_filled_params[constants.NIC_LINK]
-      msg = self.rpc.call_bridges_exist(pnode, [bridge]).fail_msg
-      if msg:
-        msg = "Error checking bridges on node '%s': %s" % (pnode, msg)
-        if self.op.force:
-          self.warn.append(msg)
-        else:
-          raise errors.OpPrereqError(msg, errors.ECODE_ENVIRON)
-
-    elif new_mode == constants.NIC_MODE_ROUTED:
-      ip = params.get(constants.INIC_IP, old_ip)
-      if ip is None:
-        raise errors.OpPrereqError("Cannot set the NIC IP address to None"
-                                   " on a routed NIC", errors.ECODE_INVAL)
-
-    elif new_mode == constants.NIC_MODE_OVS:
-      # TODO: check OVS link
-      self.LogInfo("OVS links are currently not checked for correctness")
-
-    if constants.INIC_MAC in params:
-      mac = params[constants.INIC_MAC]
-      if mac is None:
-        raise errors.OpPrereqError("Cannot unset the NIC MAC address",
-                                   errors.ECODE_INVAL)
-      elif mac in (constants.VALUE_AUTO, constants.VALUE_GENERATE):
-        # otherwise generate the MAC address
-        params[constants.INIC_MAC] = \
-          self.cfg.GenerateMAC(new_net_uuid, self.proc.GetECId())
-      else:
-        # or validate/reserve the current one
-        try:
-          self.cfg.ReserveMAC(mac, self.proc.GetECId())
-        except errors.ReservationError:
-          raise errors.OpPrereqError("MAC address '%s' already in use"
-                                     " in cluster" % mac,
-                                     errors.ECODE_NOTUNIQUE)
-    elif new_net_uuid != old_net_uuid:
-
-      def get_net_prefix(net_uuid):
-        mac_prefix = None
-        if net_uuid:
-          nobj = self.cfg.GetNetwork(net_uuid)
-          mac_prefix = nobj.mac_prefix
-
-        return mac_prefix
-
-      new_prefix = get_net_prefix(new_net_uuid)
-      old_prefix = get_net_prefix(old_net_uuid)
-      if old_prefix != new_prefix:
-        params[constants.INIC_MAC] = \
-          self.cfg.GenerateMAC(new_net_uuid, self.proc.GetECId())
-
-    # if there is a change in (ip, network) tuple
-    new_ip = params.get(constants.INIC_IP, old_ip)
-    if (new_ip, new_net_uuid) != (old_ip, old_net_uuid):
-      if new_ip:
-        # if IP is pool then require a network and generate one IP
-        if new_ip.lower() == constants.NIC_IP_POOL:
-          if new_net_uuid:
-            try:
-              new_ip = self.cfg.GenerateIp(new_net_uuid, self.proc.GetECId())
-            except errors.ReservationError:
-              raise errors.OpPrereqError("Unable to get a free IP"
-                                         " from the address pool",
-                                         errors.ECODE_STATE)
-            self.LogInfo("Chose IP %s from network %s",
-                         new_ip,
-                         new_net_obj.name)
-            params[constants.INIC_IP] = new_ip
-          else:
-            raise errors.OpPrereqError("ip=pool, but no network found",
-                                       errors.ECODE_INVAL)
-        # Reserve new IP if in the new network if any
-        elif new_net_uuid:
-          try:
-            self.cfg.ReserveIp(new_net_uuid, new_ip, self.proc.GetECId())
-            self.LogInfo("Reserving IP %s in network %s",
-                         new_ip, new_net_obj.name)
-          except errors.ReservationError:
-            raise errors.OpPrereqError("IP %s not available in network %s" %
-                                       (new_ip, new_net_obj.name),
-                                       errors.ECODE_NOTUNIQUE)
-        # new network is None so check if new IP is a conflicting IP
-        elif self.op.conflicts_check:
-          _CheckForConflictingIp(self, new_ip, pnode)
-
-      # release old IP if old network is not None
-      if old_ip and old_net_uuid:
-        try:
-          self.cfg.ReleaseIp(old_net_uuid, old_ip, self.proc.GetECId())
-        except errors.AddressPoolError:
-          logging.warning("Release IP %s not contained in network %s",
-                          old_ip, old_net_obj.name)
-
-    # there are no changes in (ip, network) tuple and old network is not None
-    elif (old_net_uuid is not None and
-          (req_link is not None or req_mode is not None)):
-      raise errors.OpPrereqError("Not allowed to change link or mode of"
-                                 " a NIC that is connected to a network",
-                                 errors.ECODE_INVAL)
-
-    private.params = new_params
-    private.filled = new_filled_params
-
-  def _PreCheckDiskTemplate(self, pnode_info):
-    """CheckPrereq checks related to a new disk template."""
-    # Arguments are passed to avoid configuration lookups
-    instance = self.instance
-    pnode = instance.primary_node
-    cluster = self.cluster
-    if instance.disk_template == self.op.disk_template:
-      raise errors.OpPrereqError("Instance already has disk template %s" %
-                                 instance.disk_template, errors.ECODE_INVAL)
-
-    if (instance.disk_template,
-        self.op.disk_template) not in self._DISK_CONVERSIONS:
-      raise errors.OpPrereqError("Unsupported disk template conversion from"
-                                 " %s to %s" % (instance.disk_template,
-                                                self.op.disk_template),
-                                 errors.ECODE_INVAL)
-    _CheckInstanceState(self, instance, INSTANCE_DOWN,
-                        msg="cannot change disk template")
-    if self.op.disk_template in constants.DTS_INT_MIRROR:
-      if self.op.remote_node == pnode:
-        raise errors.OpPrereqError("Given new secondary node %s is the same"
-                                   " as the primary node of the instance" %
-                                   self.op.remote_node, errors.ECODE_STATE)
-      _CheckNodeOnline(self, self.op.remote_node)
-      _CheckNodeNotDrained(self, self.op.remote_node)
-      # FIXME: here we assume that the old instance type is DT_PLAIN
-      assert instance.disk_template == constants.DT_PLAIN
-      disks = [{constants.IDISK_SIZE: d.size,
-                constants.IDISK_VG: d.logical_id[0]}
-               for d in instance.disks]
-      required = _ComputeDiskSizePerVG(self.op.disk_template, disks)
-      _CheckNodesFreeDiskPerVG(self, [self.op.remote_node], required)
-
-      snode_info = self.cfg.GetNodeInfo(self.op.remote_node)
-      snode_group = self.cfg.GetNodeGroup(snode_info.group)
-      ipolicy = ganeti.masterd.instance.CalculateGroupIPolicy(cluster,
-                                                              snode_group)
-      _CheckTargetNodeIPolicy(self, ipolicy, instance, snode_info, self.cfg,
-                              ignore=self.op.ignore_ipolicy)
-      if pnode_info.group != snode_info.group:
-        self.LogWarning("The primary and secondary nodes are in two"
-                        " different node groups; the disk parameters"
-                        " from the first disk's node group will be"
-                        " used")
-
-    if not self.op.disk_template in constants.DTS_EXCL_STORAGE:
-      # Make sure none of the nodes require exclusive storage
-      nodes = [pnode_info]
-      if self.op.disk_template in constants.DTS_INT_MIRROR:
-        assert snode_info
-        nodes.append(snode_info)
-      has_es = lambda n: _IsExclusiveStorageEnabledNode(self.cfg, n)
-      if compat.any(map(has_es, nodes)):
-        errmsg = ("Cannot convert disk template from %s to %s when exclusive"
-                  " storage is enabled" % (instance.disk_template,
-                                           self.op.disk_template))
-        raise errors.OpPrereqError(errmsg, errors.ECODE_STATE)
-
-  def CheckPrereq(self):
-    """Check prerequisites.
-
-    This only checks the instance list against the existing names.
-
-    """
-    assert self.op.instance_name in self.owned_locks(locking.LEVEL_INSTANCE)
-    instance = self.instance = self.cfg.GetInstanceInfo(self.op.instance_name)
-
-    cluster = self.cluster = self.cfg.GetClusterInfo()
-    assert self.instance is not None, \
-      "Cannot retrieve locked instance %s" % self.op.instance_name
-
-    pnode = instance.primary_node
-
-    self.warn = []
-
-    if (self.op.pnode is not None and self.op.pnode != pnode and
-        not self.op.force):
-      # verify that the instance is not up
-      instance_info = self.rpc.call_instance_info(pnode, instance.name,
-                                                  instance.hypervisor)
-      if instance_info.fail_msg:
-        self.warn.append("Can't get instance runtime information: %s" %
-                         instance_info.fail_msg)
-      elif instance_info.payload:
-        raise errors.OpPrereqError("Instance is still running on %s" % pnode,
-                                   errors.ECODE_STATE)
-
-    assert pnode in self.owned_locks(locking.LEVEL_NODE)
-    nodelist = list(instance.all_nodes)
-    pnode_info = self.cfg.GetNodeInfo(pnode)
-    self.diskparams = self.cfg.GetInstanceDiskParams(instance)
-
-    #_CheckInstanceNodeGroups(self.cfg, self.op.instance_name, owned_groups)
-    assert pnode_info.group in self.owned_locks(locking.LEVEL_NODEGROUP)
-    group_info = self.cfg.GetNodeGroup(pnode_info.group)
-
-    # dictionary with instance information after the modification
-    ispec = {}
-
-    # Check disk modifications. This is done here and not in CheckArguments
-    # (as with NICs), because we need to know the instance's disk template
-    if instance.disk_template == constants.DT_EXT:
-      self._CheckMods("disk", self.op.disks, {},
-                      self._VerifyDiskModification)
-    else:
-      self._CheckMods("disk", self.op.disks, constants.IDISK_PARAMS_TYPES,
-                      self._VerifyDiskModification)
-
-    # Prepare disk/NIC modifications
-    self.diskmod = PrepareContainerMods(self.op.disks, None)
-    self.nicmod = PrepareContainerMods(self.op.nics, _InstNicModPrivate)
-
-    # Check the validity of the `provider' parameter
-    if instance.disk_template in constants.DT_EXT:
-      for mod in self.diskmod:
-        ext_provider = mod[2].get(constants.IDISK_PROVIDER, None)
-        if mod[0] == constants.DDM_ADD:
-          if ext_provider is None:
-            raise errors.OpPrereqError("Instance template is '%s' and parameter"
-                                       " '%s' missing, during disk add" %
-                                       (constants.DT_EXT,
-                                        constants.IDISK_PROVIDER),
-                                       errors.ECODE_NOENT)
-        elif mod[0] == constants.DDM_MODIFY:
-          if ext_provider:
-            raise errors.OpPrereqError("Parameter '%s' is invalid during disk"
-                                       " modification" %
-                                       constants.IDISK_PROVIDER,
-                                       errors.ECODE_INVAL)
-    else:
-      for mod in self.diskmod:
-        ext_provider = mod[2].get(constants.IDISK_PROVIDER, None)
-        if ext_provider is not None:
-          raise errors.OpPrereqError("Parameter '%s' is only valid for"
-                                     " instances of type '%s'" %
-                                     (constants.IDISK_PROVIDER,
-                                      constants.DT_EXT),
-                                     errors.ECODE_INVAL)
-
-    # OS change
-    if self.op.os_name and not self.op.force:
-      _CheckNodeHasOS(self, instance.primary_node, self.op.os_name,
-                      self.op.force_variant)
-      instance_os = self.op.os_name
-    else:
-      instance_os = instance.os
-
-    assert not (self.op.disk_template and self.op.disks), \
-      "Can't modify disk template and apply disk changes at the same time"
-
-    if self.op.disk_template:
-      self._PreCheckDiskTemplate(pnode_info)
-
-    # hvparams processing
-    if self.op.hvparams:
-      hv_type = instance.hypervisor
-      i_hvdict = _GetUpdatedParams(instance.hvparams, self.op.hvparams)
-      utils.ForceDictType(i_hvdict, constants.HVS_PARAMETER_TYPES)
-      hv_new = cluster.SimpleFillHV(hv_type, instance.os, i_hvdict)
-
-      # local check
-      hypervisor.GetHypervisorClass(hv_type).CheckParameterSyntax(hv_new)
-      _CheckHVParams(self, nodelist, instance.hypervisor, hv_new)
-      self.hv_proposed = self.hv_new = hv_new # the new actual values
-      self.hv_inst = i_hvdict # the new dict (without defaults)
-    else:
-      self.hv_proposed = cluster.SimpleFillHV(instance.hypervisor, instance.os,
-                                              instance.hvparams)
-      self.hv_new = self.hv_inst = {}
-
-    # beparams processing
-    if self.op.beparams:
-      i_bedict = _GetUpdatedParams(instance.beparams, self.op.beparams,
-                                   use_none=True)
-      objects.UpgradeBeParams(i_bedict)
-      utils.ForceDictType(i_bedict, constants.BES_PARAMETER_TYPES)
-      be_new = cluster.SimpleFillBE(i_bedict)
-      self.be_proposed = self.be_new = be_new # the new actual values
-      self.be_inst = i_bedict # the new dict (without defaults)
-    else:
-      self.be_new = self.be_inst = {}
-      self.be_proposed = cluster.SimpleFillBE(instance.beparams)
-    be_old = cluster.FillBE(instance)
-
-    # CPU param validation -- checking every time a parameter is
-    # changed to cover all cases where either CPU mask or vcpus have
-    # changed
-    if (constants.BE_VCPUS in self.be_proposed and
-        constants.HV_CPU_MASK in self.hv_proposed):
-      cpu_list = \
-        utils.ParseMultiCpuMask(self.hv_proposed[constants.HV_CPU_MASK])
-      # Verify mask is consistent with number of vCPUs. Can skip this
-      # test if only 1 entry in the CPU mask, which means same mask
-      # is applied to all vCPUs.
-      if (len(cpu_list) > 1 and
-          len(cpu_list) != self.be_proposed[constants.BE_VCPUS]):
-        raise errors.OpPrereqError("Number of vCPUs [%d] does not match the"
-                                   " CPU mask [%s]" %
-                                   (self.be_proposed[constants.BE_VCPUS],
-                                    self.hv_proposed[constants.HV_CPU_MASK]),
-                                   errors.ECODE_INVAL)
-
-      # Only perform this test if a new CPU mask is given
-      if constants.HV_CPU_MASK in self.hv_new:
-        # Calculate the largest CPU number requested
-        max_requested_cpu = max(map(max, cpu_list))
-        # Check that all of the instance's nodes have enough physical CPUs to
-        # satisfy the requested CPU mask
-        _CheckNodesPhysicalCPUs(self, instance.all_nodes,
-                                max_requested_cpu + 1, instance.hypervisor)
-
-    # osparams processing
-    if self.op.osparams:
-      i_osdict = _GetUpdatedParams(instance.osparams, self.op.osparams)
-      _CheckOSParams(self, True, nodelist, instance_os, i_osdict)
-      self.os_inst = i_osdict # the new dict (without defaults)
-    else:
-      self.os_inst = {}
-
-    #TODO(dynmem): do the appropriate check involving MINMEM
-    if (constants.BE_MAXMEM in self.op.beparams and not self.op.force and
-        be_new[constants.BE_MAXMEM] > be_old[constants.BE_MAXMEM]):
-      mem_check_list = [pnode]
-      if be_new[constants.BE_AUTO_BALANCE]:
-        # either we changed auto_balance to yes or it was from before
-        mem_check_list.extend(instance.secondary_nodes)
-      instance_info = self.rpc.call_instance_info(pnode, instance.name,
-                                                  instance.hypervisor)
-      nodeinfo = self.rpc.call_node_info(mem_check_list, None,
-                                         [instance.hypervisor], False)
-      pninfo = nodeinfo[pnode]
-      msg = pninfo.fail_msg
-      if msg:
-        # Assume the primary node is unreachable and go ahead
-        self.warn.append("Can't get info from primary node %s: %s" %
-                         (pnode, msg))
-      else:
-        (_, _, (pnhvinfo, )) = pninfo.payload
-        if not isinstance(pnhvinfo.get("memory_free", None), int):
-          self.warn.append("Node data from primary node %s doesn't contain"
-                           " free memory information" % pnode)
-        elif instance_info.fail_msg:
-          self.warn.append("Can't get instance runtime information: %s" %
-                           instance_info.fail_msg)
-        else:
-          if instance_info.payload:
-            current_mem = int(instance_info.payload["memory"])
-          else:
-            # Assume instance not running
-            # (there is a slight race condition here, but it's not very
-            # probable, and we have no other way to check)
-            # TODO: Describe race condition
-            current_mem = 0
-          #TODO(dynmem): do the appropriate check involving MINMEM
-          miss_mem = (be_new[constants.BE_MAXMEM] - current_mem -
-                      pnhvinfo["memory_free"])
-          if miss_mem > 0:
-            raise errors.OpPrereqError("This change will prevent the instance"
-                                       " from starting, due to %d MB of memory"
-                                       " missing on its primary node" %
-                                       miss_mem, errors.ECODE_NORES)
-
-      if be_new[constants.BE_AUTO_BALANCE]:
-        for node, nres in nodeinfo.items():
-          if node not in instance.secondary_nodes:
-            continue
-          nres.Raise("Can't get info from secondary node %s" % node,
-                     prereq=True, ecode=errors.ECODE_STATE)
-          (_, _, (nhvinfo, )) = nres.payload
-          if not isinstance(nhvinfo.get("memory_free", None), int):
-            raise errors.OpPrereqError("Secondary node %s didn't return free"
-                                       " memory information" % node,
-                                       errors.ECODE_STATE)
-          #TODO(dynmem): do the appropriate check involving MINMEM
-          elif be_new[constants.BE_MAXMEM] > nhvinfo["memory_free"]:
-            raise errors.OpPrereqError("This change will prevent the instance"
-                                       " from failover to its secondary node"
-                                       " %s, due to not enough memory" % node,
-                                       errors.ECODE_STATE)
-
-    if self.op.runtime_mem:
-      remote_info = self.rpc.call_instance_info(instance.primary_node,
-                                                instance.name,
-                                                instance.hypervisor)
-      remote_info.Raise("Error checking node %s" % instance.primary_node)
-      if not remote_info.payload: # not running already
-        raise errors.OpPrereqError("Instance %s is not running" %
-                                   instance.name, errors.ECODE_STATE)
-
-      current_memory = remote_info.payload["memory"]
-      if (not self.op.force and
-           (self.op.runtime_mem > self.be_proposed[constants.BE_MAXMEM] or
-            self.op.runtime_mem < self.be_proposed[constants.BE_MINMEM])):
-        raise errors.OpPrereqError("Instance %s must have memory between %d"
-                                   " and %d MB of memory unless --force is"
-                                   " given" %
-                                   (instance.name,
-                                    self.be_proposed[constants.BE_MINMEM],
-                                    self.be_proposed[constants.BE_MAXMEM]),
-                                   errors.ECODE_INVAL)
-
-      delta = self.op.runtime_mem - current_memory
-      if delta > 0:
-        _CheckNodeFreeMemory(self, instance.primary_node,
-                             "ballooning memory for instance %s" %
-                             instance.name, delta, instance.hypervisor)
-
-    if self.op.disks and instance.disk_template == constants.DT_DISKLESS:
-      raise errors.OpPrereqError("Disk operations not supported for"
-                                 " diskless instances", errors.ECODE_INVAL)
-
-    def _PrepareNicCreate(_, params, private):
-      self._PrepareNicModification(params, private, None, None,
-                                   {}, cluster, pnode)
-      return (None, None)
-
-    def _PrepareNicMod(_, nic, params, private):
-      self._PrepareNicModification(params, private, nic.ip, nic.network,
-                                   nic.nicparams, cluster, pnode)
-      return None
-
-    def _PrepareNicRemove(_, params, __):
-      ip = params.ip
-      net = params.network
-      if net is not None and ip is not None:
-        self.cfg.ReleaseIp(net, ip, self.proc.GetECId())
-
-    # Verify NIC changes (operating on copy)
-    nics = instance.nics[:]
-    ApplyContainerMods("NIC", nics, None, self.nicmod,
-                       _PrepareNicCreate, _PrepareNicMod, _PrepareNicRemove)
-    if len(nics) > constants.MAX_NICS:
-      raise errors.OpPrereqError("Instance has too many network interfaces"
-                                 " (%d), cannot add more" % constants.MAX_NICS,
-                                 errors.ECODE_STATE)
-
-    def _PrepareDiskMod(_, disk, params, __):
-      disk.name = params.get(constants.IDISK_NAME, None)
-
-    # Verify disk changes (operating on a copy)
-    disks = copy.deepcopy(instance.disks)
-    ApplyContainerMods("disk", disks, None, self.diskmod, None, _PrepareDiskMod,
-                       None)
-    utils.ValidateDeviceNames("disk", disks)
-    if len(disks) > constants.MAX_DISKS:
-      raise errors.OpPrereqError("Instance has too many disks (%d), cannot add"
-                                 " more" % constants.MAX_DISKS,
-                                 errors.ECODE_STATE)
-    disk_sizes = [disk.size for disk in instance.disks]
-    disk_sizes.extend(params["size"] for (op, idx, params, private) in
-                      self.diskmod if op == constants.DDM_ADD)
-    ispec[constants.ISPEC_DISK_COUNT] = len(disk_sizes)
-    ispec[constants.ISPEC_DISK_SIZE] = disk_sizes
-
-    if self.op.offline is not None and self.op.offline:
-      _CheckInstanceState(self, instance, CAN_CHANGE_INSTANCE_OFFLINE,
-                          msg="can't change to offline")
-
-    # Pre-compute NIC changes (necessary to use result in hooks)
-    self._nic_chgdesc = []
-    if self.nicmod:
-      # Operate on copies as this is still in prereq
-      nics = [nic.Copy() for nic in instance.nics]
-      ApplyContainerMods("NIC", nics, self._nic_chgdesc, self.nicmod,
-                         self._CreateNewNic, self._ApplyNicMods, None)
-      # Verify that NIC names are unique and valid
-      utils.ValidateDeviceNames("NIC", nics)
-      self._new_nics = nics
-      ispec[constants.ISPEC_NIC_COUNT] = len(self._new_nics)
-    else:
-      self._new_nics = None
-      ispec[constants.ISPEC_NIC_COUNT] = len(instance.nics)
-
-    if not self.op.ignore_ipolicy:
-      ipolicy = ganeti.masterd.instance.CalculateGroupIPolicy(cluster,
-                                                              group_info)
-
-      # Fill ispec with backend parameters
-      ispec[constants.ISPEC_SPINDLE_USE] = \
-        self.be_new.get(constants.BE_SPINDLE_USE, None)
-      ispec[constants.ISPEC_CPU_COUNT] = self.be_new.get(constants.BE_VCPUS,
-                                                         None)
-
-      # Copy ispec to verify parameters with min/max values separately
-      if self.op.disk_template:
-        new_disk_template = self.op.disk_template
-      else:
-        new_disk_template = instance.disk_template
-      ispec_max = ispec.copy()
-      ispec_max[constants.ISPEC_MEM_SIZE] = \
-        self.be_new.get(constants.BE_MAXMEM, None)
-      res_max = _ComputeIPolicyInstanceSpecViolation(ipolicy, ispec_max,
-                                                     new_disk_template)
-      ispec_min = ispec.copy()
-      ispec_min[constants.ISPEC_MEM_SIZE] = \
-        self.be_new.get(constants.BE_MINMEM, None)
-      res_min = _ComputeIPolicyInstanceSpecViolation(ipolicy, ispec_min,
-                                                     new_disk_template)
-
-      if (res_max or res_min):
-        # FIXME: Improve error message by including information about whether
-        # the upper or lower limit of the parameter fails the ipolicy.
-        msg = ("Instance allocation to group %s (%s) violates policy: %s" %
-               (group_info, group_info.name,
-                utils.CommaJoin(set(res_max + res_min))))
-        raise errors.OpPrereqError(msg, errors.ECODE_INVAL)
-
-  def _ConvertPlainToDrbd(self, feedback_fn):
-    """Converts an instance from plain to drbd.
-
-    """
-    feedback_fn("Converting template to drbd")
-    instance = self.instance
-    pnode = instance.primary_node
-    snode = self.op.remote_node
-
-    assert instance.disk_template == constants.DT_PLAIN
-
-    # create a fake disk info for _GenerateDiskTemplate
-    disk_info = [{constants.IDISK_SIZE: d.size, constants.IDISK_MODE: d.mode,
-                  constants.IDISK_VG: d.logical_id[0],
-                  constants.IDISK_NAME: d.name}
-                 for d in instance.disks]
-    new_disks = _GenerateDiskTemplate(self, self.op.disk_template,
-                                      instance.name, pnode, [snode],
-                                      disk_info, None, None, 0, feedback_fn,
-                                      self.diskparams)
-    anno_disks = rpc.AnnotateDiskParams(constants.DT_DRBD8, new_disks,
-                                        self.diskparams)
-    p_excl_stor = _IsExclusiveStorageEnabledNodeName(self.cfg, pnode)
-    s_excl_stor = _IsExclusiveStorageEnabledNodeName(self.cfg, snode)
-    info = _GetInstanceInfoText(instance)
-    feedback_fn("Creating additional volumes...")
-    # first, create the missing data and meta devices
-    for disk in anno_disks:
-      # unfortunately this is... not too nice
-      _CreateSingleBlockDev(self, pnode, instance, disk.children[1],
-                            info, True, p_excl_stor)
-      for child in disk.children:
-        _CreateSingleBlockDev(self, snode, instance, child, info, True,
-                              s_excl_stor)
-    # at this stage, all new LVs have been created, we can rename the
-    # old ones
-    feedback_fn("Renaming original volumes...")
-    rename_list = [(o, n.children[0].logical_id)
-                   for (o, n) in zip(instance.disks, new_disks)]
-    result = self.rpc.call_blockdev_rename(pnode, rename_list)
-    result.Raise("Failed to rename original LVs")
-
-    feedback_fn("Initializing DRBD devices...")
-    # all child devices are in place, we can now create the DRBD devices
-    try:
-      for disk in anno_disks:
-        for (node, excl_stor) in [(pnode, p_excl_stor), (snode, s_excl_stor)]:
-          f_create = node == pnode
-          _CreateSingleBlockDev(self, node, instance, disk, info, f_create,
-                                excl_stor)
-    except errors.GenericError, e:
-      feedback_fn("Initializing of DRBD devices failed;"
-                  " renaming back original volumes...")
-      for disk in new_disks:
-        self.cfg.SetDiskID(disk, pnode)
-      rename_back_list = [(n.children[0], o.logical_id)
-                          for (n, o) in zip(new_disks, instance.disks)]
-      result = self.rpc.call_blockdev_rename(pnode, rename_back_list)
-      result.Raise("Failed to rename LVs back after error %s" % str(e))
-      raise
-
-    # at this point, the instance has been modified
-    instance.disk_template = constants.DT_DRBD8
-    instance.disks = new_disks
-    self.cfg.Update(instance, feedback_fn)
-
-    # Release node locks while waiting for sync
-    _ReleaseLocks(self, locking.LEVEL_NODE)
-
-    # disks are created, waiting for sync
-    disk_abort = not _WaitForSync(self, instance,
-                                  oneshot=not self.op.wait_for_sync)
-    if disk_abort:
-      raise errors.OpExecError("There are some degraded disks for"
-                               " this instance, please cleanup manually")
-
-    # Node resource locks will be released by caller
-
-  def _ConvertDrbdToPlain(self, feedback_fn):
-    """Converts an instance from drbd to plain.
-
-    """
-    instance = self.instance
-
-    assert len(instance.secondary_nodes) == 1
-    assert instance.disk_template == constants.DT_DRBD8
-
-    pnode = instance.primary_node
-    snode = instance.secondary_nodes[0]
-    feedback_fn("Converting template to plain")
-
-    old_disks = _AnnotateDiskParams(instance, instance.disks, self.cfg)
-    new_disks = [d.children[0] for d in instance.disks]
-
-    # copy over size, mode and name
-    for parent, child in zip(old_disks, new_disks):
-      child.size = parent.size
-      child.mode = parent.mode
-      child.name = parent.name
-
-    # this is a DRBD disk, return its port to the pool
-    # NOTE: this must be done right before the call to cfg.Update!
-    for disk in old_disks:
-      tcp_port = disk.logical_id[2]
-      self.cfg.AddTcpUdpPort(tcp_port)
-
-    # update instance structure
-    instance.disks = new_disks
-    instance.disk_template = constants.DT_PLAIN
-    _UpdateIvNames(0, instance.disks)
-    self.cfg.Update(instance, feedback_fn)
-
-    # Release locks in case removing disks takes a while
-    _ReleaseLocks(self, locking.LEVEL_NODE)
-
-    feedback_fn("Removing volumes on the secondary node...")
-    for disk in old_disks:
-      self.cfg.SetDiskID(disk, snode)
-      msg = self.rpc.call_blockdev_remove(snode, disk).fail_msg
-      if msg:
-        self.LogWarning("Could not remove block device %s on node %s,"
-                        " continuing anyway: %s", disk.iv_name, snode, msg)
-
-    feedback_fn("Removing unneeded volumes on the primary node...")
-    for idx, disk in enumerate(old_disks):
-      meta = disk.children[1]
-      self.cfg.SetDiskID(meta, pnode)
-      msg = self.rpc.call_blockdev_remove(pnode, meta).fail_msg
-      if msg:
-        self.LogWarning("Could not remove metadata for disk %d on node %s,"
-                        " continuing anyway: %s", idx, pnode, msg)
-
-  def _CreateNewDisk(self, idx, params, _):
-    """Creates a new disk.
-
-    """
-    instance = self.instance
-
-    # add a new disk
-    if instance.disk_template in constants.DTS_FILEBASED:
-      (file_driver, file_path) = instance.disks[0].logical_id
-      file_path = os.path.dirname(file_path)
-    else:
-      file_driver = file_path = None
-
-    disk = \
-      _GenerateDiskTemplate(self, instance.disk_template, instance.name,
-                            instance.primary_node, instance.secondary_nodes,
-                            [params], file_path, file_driver, idx,
-                            self.Log, self.diskparams)[0]
-
-    info = _GetInstanceInfoText(instance)
-
-    logging.info("Creating volume %s for instance %s",
-                 disk.iv_name, instance.name)
-    # Note: this needs to be kept in sync with _CreateDisks
-    #HARDCODE
-    for node in instance.all_nodes:
-      f_create = (node == instance.primary_node)
-      try:
-        _CreateBlockDev(self, node, instance, disk, f_create, info, f_create)
-      except errors.OpExecError, err:
-        self.LogWarning("Failed to create volume %s (%s) on node '%s': %s",
-                        disk.iv_name, disk, node, err)
-
-    if self.cluster.prealloc_wipe_disks:
-      # Wipe new disk
-      _WipeDisks(self, instance,
-                 disks=[(idx, disk, 0)])
-
-    return (disk, [
-      ("disk/%d" % idx, "add:size=%s,mode=%s" % (disk.size, disk.mode)),
-      ])
-
-  @staticmethod
-  def _ModifyDisk(idx, disk, params, _):
-    """Modifies a disk.
-
-    """
-    changes = []
-    mode = params.get(constants.IDISK_MODE, None)
-    if mode:
-      disk.mode = mode
-      changes.append(("disk.mode/%d" % idx, disk.mode))
-
-    name = params.get(constants.IDISK_NAME, None)
-    disk.name = name
-    changes.append(("disk.name/%d" % idx, disk.name))
-
-    return changes
-
-  def _RemoveDisk(self, idx, root, _):
-    """Removes a disk.
-
-    """
-    (anno_disk,) = _AnnotateDiskParams(self.instance, [root], self.cfg)
-    for node, disk in anno_disk.ComputeNodeTree(self.instance.primary_node):
-      self.cfg.SetDiskID(disk, node)
-      msg = self.rpc.call_blockdev_remove(node, disk).fail_msg
-      if msg:
-        self.LogWarning("Could not remove disk/%d on node '%s': %s,"
-                        " continuing anyway", idx, node, msg)
-
-    # if this is a DRBD disk, return its port to the pool
-    if root.dev_type in constants.LDS_DRBD:
-      self.cfg.AddTcpUdpPort(root.logical_id[2])
-
-  def _CreateNewNic(self, idx, params, private):
-    """Creates data structure for a new network interface.
-
-    """
-    mac = params[constants.INIC_MAC]
-    ip = params.get(constants.INIC_IP, None)
-    net = params.get(constants.INIC_NETWORK, None)
-    name = params.get(constants.INIC_NAME, None)
-    net_uuid = self.cfg.LookupNetwork(net)
-    #TODO: not private.filled?? can a nic have no nicparams??
-    nicparams = private.filled
-    nobj = objects.NIC(mac=mac, ip=ip, network=net_uuid, name=name,
-                       nicparams=nicparams)
-    nobj.uuid = self.cfg.GenerateUniqueID(self.proc.GetECId())
-
-    return (nobj, [
-      ("nic.%d" % idx,
-       "add:mac=%s,ip=%s,mode=%s,link=%s,network=%s" %
-       (mac, ip, private.filled[constants.NIC_MODE],
-       private.filled[constants.NIC_LINK],
-       net)),
-      ])
-
-  def _ApplyNicMods(self, idx, nic, params, private):
-    """Modifies a network interface.
-
-    """
-    changes = []
-
-    for key in [constants.INIC_MAC, constants.INIC_IP, constants.INIC_NAME]:
-      if key in params:
-        changes.append(("nic.%s/%d" % (key, idx), params[key]))
-        setattr(nic, key, params[key])
-
-    new_net = params.get(constants.INIC_NETWORK, nic.network)
-    new_net_uuid = self.cfg.LookupNetwork(new_net)
-    if new_net_uuid != nic.network:
-      changes.append(("nic.network/%d" % idx, new_net))
-      nic.network = new_net_uuid
-
-    if private.filled:
-      nic.nicparams = private.filled
-
-      for (key, val) in nic.nicparams.items():
-        changes.append(("nic.%s/%d" % (key, idx), val))
-
-    return changes
-
-  def Exec(self, feedback_fn):
-    """Modifies an instance.
-
-    All parameters take effect only at the next restart of the instance.
-
-    """
-    # Process here the warnings from CheckPrereq, as we don't have a
-    # feedback_fn there.
-    # TODO: Replace with self.LogWarning
-    for warn in self.warn:
-      feedback_fn("WARNING: %s" % warn)
-
-    assert ((self.op.disk_template is None) ^
-            bool(self.owned_locks(locking.LEVEL_NODE_RES))), \
-      "Not owning any node resource locks"
-
-    result = []
-    instance = self.instance
-
-    # New primary node
-    if self.op.pnode:
-      instance.primary_node = self.op.pnode
-
-    # runtime memory
-    if self.op.runtime_mem:
-      rpcres = self.rpc.call_instance_balloon_memory(instance.primary_node,
-                                                     instance,
-                                                     self.op.runtime_mem)
-      rpcres.Raise("Cannot modify instance runtime memory")
-      result.append(("runtime_memory", self.op.runtime_mem))
-
-    # Apply disk changes
-    ApplyContainerMods("disk", instance.disks, result, self.diskmod,
-                       self._CreateNewDisk, self._ModifyDisk, self._RemoveDisk)
-    _UpdateIvNames(0, instance.disks)
-
-    if self.op.disk_template:
-      if __debug__:
-        check_nodes = set(instance.all_nodes)
-        if self.op.remote_node:
-          check_nodes.add(self.op.remote_node)
-        for level in [locking.LEVEL_NODE, locking.LEVEL_NODE_RES]:
-          owned = self.owned_locks(level)
-          assert not (check_nodes - owned), \
-            ("Not owning the correct locks, owning %r, expected at least %r" %
-             (owned, check_nodes))
-
-      r_shut = _ShutdownInstanceDisks(self, instance)
-      if not r_shut:
-        raise errors.OpExecError("Cannot shutdown instance disks, unable to"
-                                 " proceed with disk template conversion")
-      mode = (instance.disk_template, self.op.disk_template)
-      try:
-        self._DISK_CONVERSIONS[mode](self, feedback_fn)
-      except:
-        self.cfg.ReleaseDRBDMinors(instance.name)
-        raise
-      result.append(("disk_template", self.op.disk_template))
-
-      assert instance.disk_template == self.op.disk_template, \
-        ("Expected disk template '%s', found '%s'" %
-         (self.op.disk_template, instance.disk_template))
-
-    # Release node and resource locks if there are any (they might already have
-    # been released during disk conversion)
-    _ReleaseLocks(self, locking.LEVEL_NODE)
-    _ReleaseLocks(self, locking.LEVEL_NODE_RES)
-
-    # Apply NIC changes
-    if self._new_nics is not None:
-      instance.nics = self._new_nics
-      result.extend(self._nic_chgdesc)
-
-    # hvparams changes
-    if self.op.hvparams:
-      instance.hvparams = self.hv_inst
-      for key, val in self.op.hvparams.iteritems():
-        result.append(("hv/%s" % key, val))
-
-    # beparams changes
-    if self.op.beparams:
-      instance.beparams = self.be_inst
-      for key, val in self.op.beparams.iteritems():
-        result.append(("be/%s" % key, val))
-
-    # OS change
-    if self.op.os_name:
-      instance.os = self.op.os_name
-
-    # osparams changes
-    if self.op.osparams:
-      instance.osparams = self.os_inst
-      for key, val in self.op.osparams.iteritems():
-        result.append(("os/%s" % key, val))
-
-    if self.op.offline is None:
-      # Ignore
-      pass
-    elif self.op.offline:
-      # Mark instance as offline
-      self.cfg.MarkInstanceOffline(instance.name)
-      result.append(("admin_state", constants.ADMINST_OFFLINE))
-    else:
-      # Mark instance as online, but stopped
-      self.cfg.MarkInstanceDown(instance.name)
-      result.append(("admin_state", constants.ADMINST_DOWN))
-
-    self.cfg.Update(instance, feedback_fn, self.proc.GetECId())
-
-    assert not (self.owned_locks(locking.LEVEL_NODE_RES) or
-                self.owned_locks(locking.LEVEL_NODE)), \
-      "All node locks should have been released by now"
-
-    return result
-
-  _DISK_CONVERSIONS = {
-    (constants.DT_PLAIN, constants.DT_DRBD8): _ConvertPlainToDrbd,
-    (constants.DT_DRBD8, constants.DT_PLAIN): _ConvertDrbdToPlain,
-    }
-
-
-class LUInstanceChangeGroup(LogicalUnit):
-  HPATH = "instance-change-group"
-  HTYPE = constants.HTYPE_INSTANCE
-  REQ_BGL = False
-
-  def ExpandNames(self):
-    self.share_locks = _ShareAll()
-
-    self.needed_locks = {
-      locking.LEVEL_NODEGROUP: [],
-      locking.LEVEL_NODE: [],
-      locking.LEVEL_NODE_ALLOC: locking.ALL_SET,
-      }
-
-    self._ExpandAndLockInstance()
-
-    if self.op.target_groups:
-      self.req_target_uuids = map(self.cfg.LookupNodeGroup,
-                                  self.op.target_groups)
-    else:
-      self.req_target_uuids = None
-
-    self.op.iallocator = _GetDefaultIAllocator(self.cfg, self.op.iallocator)
-
-  def DeclareLocks(self, level):
-    if level == locking.LEVEL_NODEGROUP:
-      assert not self.needed_locks[locking.LEVEL_NODEGROUP]
-
-      if self.req_target_uuids:
-        lock_groups = set(self.req_target_uuids)
-
-        # Lock all groups used by instance optimistically; this requires going
-        # via the node before it's locked, requiring verification later on
-        instance_groups = self.cfg.GetInstanceNodeGroups(self.op.instance_name)
-        lock_groups.update(instance_groups)
-      else:
-        # No target groups, need to lock all of them
-        lock_groups = locking.ALL_SET
-
-      self.needed_locks[locking.LEVEL_NODEGROUP] = lock_groups
-
-    elif level == locking.LEVEL_NODE:
-      if self.req_target_uuids:
-        # Lock all nodes used by instances
-        self.recalculate_locks[locking.LEVEL_NODE] = constants.LOCKS_APPEND
-        self._LockInstancesNodes()
-
-        # Lock all nodes in all potential target groups
-        lock_groups = (frozenset(self.owned_locks(locking.LEVEL_NODEGROUP)) -
-                       self.cfg.GetInstanceNodeGroups(self.op.instance_name))
-        member_nodes = [node_name
-                        for group in lock_groups
-                        for node_name in self.cfg.GetNodeGroup(group).members]
-        self.needed_locks[locking.LEVEL_NODE].extend(member_nodes)
-      else:
-        # Lock all nodes as all groups are potential targets
-        self.needed_locks[locking.LEVEL_NODE] = locking.ALL_SET
-
-  def CheckPrereq(self):
-    owned_instances = frozenset(self.owned_locks(locking.LEVEL_INSTANCE))
-    owned_groups = frozenset(self.owned_locks(locking.LEVEL_NODEGROUP))
-    owned_nodes = frozenset(self.owned_locks(locking.LEVEL_NODE))
-
-    assert (self.req_target_uuids is None or
-            owned_groups.issuperset(self.req_target_uuids))
-    assert owned_instances == set([self.op.instance_name])
-
-    # Get instance information
-    self.instance = self.cfg.GetInstanceInfo(self.op.instance_name)
-
-    # Check if node groups for locked instance are still correct
-    assert owned_nodes.issuperset(self.instance.all_nodes), \
-      ("Instance %s's nodes changed while we kept the lock" %
-       self.op.instance_name)
-
-    inst_groups = _CheckInstanceNodeGroups(self.cfg, self.op.instance_name,
-                                           owned_groups)
-
-    if self.req_target_uuids:
-      # User requested specific target groups
-      self.target_uuids = frozenset(self.req_target_uuids)
-    else:
-      # All groups except those used by the instance are potential targets
-      self.target_uuids = owned_groups - inst_groups
-
-    conflicting_groups = self.target_uuids & inst_groups
-    if conflicting_groups:
-      raise errors.OpPrereqError("Can't use group(s) '%s' as targets, they are"
-                                 " used by the instance '%s'" %
-                                 (utils.CommaJoin(conflicting_groups),
-                                  self.op.instance_name),
-                                 errors.ECODE_INVAL)
-
-    if not self.target_uuids:
-      raise errors.OpPrereqError("There are no possible target groups",
-                                 errors.ECODE_INVAL)
-
-  def BuildHooksEnv(self):
-    """Build hooks env.
-
-    """
-    assert self.target_uuids
-
-    env = {
-      "TARGET_GROUPS": " ".join(self.target_uuids),
-      }
-
-    env.update(_BuildInstanceHookEnvByObject(self, self.instance))
-
-    return env
-
-  def BuildHooksNodes(self):
-    """Build hooks nodes.
-
-    """
-    mn = self.cfg.GetMasterNode()
-    return ([mn], [mn])
-
-  def Exec(self, feedback_fn):
-    instances = list(self.owned_locks(locking.LEVEL_INSTANCE))
-
-    assert instances == [self.op.instance_name], "Instance not locked"
-
-    req = iallocator.IAReqGroupChange(instances=instances,
-                                      target_groups=list(self.target_uuids))
-    ial = iallocator.IAllocator(self.cfg, self.rpc, req)
-
-    ial.Run(self.op.iallocator)
-
-    if not ial.success:
-      raise errors.OpPrereqError("Can't compute solution for changing group of"
-                                 " instance '%s' using iallocator '%s': %s" %
-                                 (self.op.instance_name, self.op.iallocator,
-                                  ial.info), errors.ECODE_NORES)
-
-    jobs = _LoadNodeEvacResult(self, ial.result, self.op.early_release, False)
-
-    self.LogInfo("Iallocator returned %s job(s) for changing group of"
-                 " instance '%s'", len(jobs), self.op.instance_name)
-
-    return ResultWithJobs(jobs)
-
-
-def _CheckDiskConsistencyInner(lu, instance, dev, node, on_primary,
-                               ldisk=False):
-  """Check that mirrors are not degraded.
-
-  @attention: The device has to be annotated already.
-
-  The ldisk parameter, if True, will change the test from the
-  is_degraded attribute (which represents overall non-ok status for
-  the device(s)) to the ldisk (representing the local storage status).
-
-  """
-  lu.cfg.SetDiskID(dev, node)
-
-  result = True
-
-  if on_primary or dev.AssembleOnSecondary():
-    rstats = lu.rpc.call_blockdev_find(node, dev)
-    msg = rstats.fail_msg
-    if msg:
-      lu.LogWarning("Can't find disk on node %s: %s", node, msg)
-      result = False
-    elif not rstats.payload:
-      lu.LogWarning("Can't find disk on node %s", node)
-      result = False
+    # OS change
+    if self.op.os_name and not self.op.force:
+      CheckNodeHasOS(self, instance.primary_node, self.op.os_name,
+                     self.op.force_variant)
+      instance_os = self.op.os_name
     else:
-      if ldisk:
-        result = result and rstats.payload.ldisk_status == constants.LDS_OKAY
-      else:
-        result = result and not rstats.payload.is_degraded
-
-  if dev.children:
-    for child in dev.children:
-      result = result and _CheckDiskConsistencyInner(lu, instance, child, node,
-                                                     on_primary)
-
-  return result
-
-
-def _CheckDiskConsistency(lu, instance, dev, node, on_primary, ldisk=False):
-  """Wrapper around L{_CheckDiskConsistencyInner}.
-
-  """
-  (disk,) = _AnnotateDiskParams(instance, [dev], lu.cfg)
-  return _CheckDiskConsistencyInner(lu, instance, disk, node, on_primary,
-                                    ldisk=ldisk)
-
-
-class TLMigrateInstance(Tasklet):
-  """Tasklet class for instance migration.
-
-  @type live: boolean
-  @ivar live: whether the migration will be done live or non-live;
-      this variable is initalized only after CheckPrereq has run
-  @type cleanup: boolean
-  @ivar cleanup: Wheater we cleanup from a failed migration
-  @type iallocator: string
-  @ivar iallocator: The iallocator used to determine target_node
-  @type target_node: string
-  @ivar target_node: If given, the target_node to reallocate the instance to
-  @type failover: boolean
-  @ivar failover: Whether operation results in failover or migration
-  @type fallback: boolean
-  @ivar fallback: Whether fallback to failover is allowed if migration not
-                  possible
-  @type ignore_consistency: boolean
-  @ivar ignore_consistency: Wheter we should ignore consistency between source
-                            and target node
-  @type shutdown_timeout: int
-  @ivar shutdown_timeout: In case of failover timeout of the shutdown
-  @type ignore_ipolicy: bool
-  @ivar ignore_ipolicy: If true, we can ignore instance policy when migrating
-
-  """
-
-  # Constants
-  _MIGRATION_POLL_INTERVAL = 1      # seconds
-  _MIGRATION_FEEDBACK_INTERVAL = 10 # seconds
-
-  def __init__(self, lu, instance_name, cleanup, failover, fallback,
-               ignore_consistency, allow_runtime_changes, shutdown_timeout,
-               ignore_ipolicy):
-    """Initializes this class.
-
-    """
-    Tasklet.__init__(self, lu)
-
-    # Parameters
-    self.instance_name = instance_name
-    self.cleanup = cleanup
-    self.live = False # will be overridden later
-    self.failover = failover
-    self.fallback = fallback
-    self.ignore_consistency = ignore_consistency
-    self.shutdown_timeout = shutdown_timeout
-    self.ignore_ipolicy = ignore_ipolicy
-    self.allow_runtime_changes = allow_runtime_changes
-
-  def CheckPrereq(self):
-    """Check prerequisites.
-
-    This checks that the instance is in the cluster.
+      instance_os = instance.os
 
-    """
-    instance_name = _ExpandInstanceName(self.lu.cfg, self.instance_name)
-    instance = self.cfg.GetInstanceInfo(instance_name)
-    assert instance is not None
-    self.instance = instance
-    cluster = self.cfg.GetClusterInfo()
+    assert not (self.op.disk_template and self.op.disks), \
+      "Can't modify disk template and apply disk changes at the same time"
 
-    if (not self.cleanup and
-        not instance.admin_state == constants.ADMINST_UP and
-        not self.failover and self.fallback):
-      self.lu.LogInfo("Instance is marked down or offline, fallback allowed,"
-                      " switching to failover")
-      self.failover = True
+    if self.op.disk_template:
+      self._PreCheckDiskTemplate(pnode_info)
 
-    if instance.disk_template not in constants.DTS_MIRRORED:
-      if self.failover:
-        text = "failovers"
-      else:
-        text = "migrations"
-      raise errors.OpPrereqError("Instance's disk layout '%s' does not allow"
-                                 " %s" % (instance.disk_template, text),
-                                 errors.ECODE_STATE)
+    # hvparams processing
+    if self.op.hvparams:
+      hv_type = instance.hypervisor
+      i_hvdict = GetUpdatedParams(instance.hvparams, self.op.hvparams)
+      utils.ForceDictType(i_hvdict, constants.HVS_PARAMETER_TYPES)
+      hv_new = cluster.SimpleFillHV(hv_type, instance.os, i_hvdict)
 
-    if instance.disk_template in constants.DTS_EXT_MIRROR:
-      _CheckIAllocatorOrNode(self.lu, "iallocator", "target_node")
+      # local check
+      hypervisor.GetHypervisorClass(hv_type).CheckParameterSyntax(hv_new)
+      CheckHVParams(self, nodelist, instance.hypervisor, hv_new)
+      self.hv_proposed = self.hv_new = hv_new # the new actual values
+      self.hv_inst = i_hvdict # the new dict (without defaults)
+    else:
+      self.hv_proposed = cluster.SimpleFillHV(instance.hypervisor, instance.os,
+                                              instance.hvparams)
+      self.hv_new = self.hv_inst = {}
 
-      if self.lu.op.iallocator:
-        assert locking.NAL in self.lu.owned_locks(locking.LEVEL_NODE_ALLOC)
-        self._RunAllocator()
-      else:
-        # We set set self.target_node as it is required by
-        # BuildHooksEnv
-        self.target_node = self.lu.op.target_node
+    # beparams processing
+    if self.op.beparams:
+      i_bedict = GetUpdatedParams(instance.beparams, self.op.beparams,
+                                  use_none=True)
+      objects.UpgradeBeParams(i_bedict)
+      utils.ForceDictType(i_bedict, constants.BES_PARAMETER_TYPES)
+      be_new = cluster.SimpleFillBE(i_bedict)
+      self.be_proposed = self.be_new = be_new # the new actual values
+      self.be_inst = i_bedict # the new dict (without defaults)
+    else:
+      self.be_new = self.be_inst = {}
+      self.be_proposed = cluster.SimpleFillBE(instance.beparams)
+    be_old = cluster.FillBE(instance)
 
-      # Check that the target node is correct in terms of instance policy
-      nodeinfo = self.cfg.GetNodeInfo(self.target_node)
-      group_info = self.cfg.GetNodeGroup(nodeinfo.group)
-      ipolicy = ganeti.masterd.instance.CalculateGroupIPolicy(cluster,
-                                                              group_info)
-      _CheckTargetNodeIPolicy(self.lu, ipolicy, instance, nodeinfo, self.cfg,
-                              ignore=self.ignore_ipolicy)
-
-      # self.target_node is already populated, either directly or by the
-      # iallocator run
-      target_node = self.target_node
-      if self.target_node == instance.primary_node:
-        raise errors.OpPrereqError("Cannot migrate instance %s"
-                                   " to its primary (%s)" %
-                                   (instance.name, instance.primary_node),
-                                   errors.ECODE_STATE)
+    # CPU param validation -- checking every time a parameter is
+    # changed to cover all cases where either CPU mask or vcpus have
+    # changed
+    if (constants.BE_VCPUS in self.be_proposed and
+        constants.HV_CPU_MASK in self.hv_proposed):
+      cpu_list = \
+        utils.ParseMultiCpuMask(self.hv_proposed[constants.HV_CPU_MASK])
+      # Verify mask is consistent with number of vCPUs. Can skip this
+      # test if only 1 entry in the CPU mask, which means same mask
+      # is applied to all vCPUs.
+      if (len(cpu_list) > 1 and
+          len(cpu_list) != self.be_proposed[constants.BE_VCPUS]):
+        raise errors.OpPrereqError("Number of vCPUs [%d] does not match the"
+                                   " CPU mask [%s]" %
+                                   (self.be_proposed[constants.BE_VCPUS],
+                                    self.hv_proposed[constants.HV_CPU_MASK]),
+                                   errors.ECODE_INVAL)
 
-      if len(self.lu.tasklets) == 1:
-        # It is safe to release locks only when we're the only tasklet
-        # in the LU
-        _ReleaseLocks(self.lu, locking.LEVEL_NODE,
-                      keep=[instance.primary_node, self.target_node])
-        _ReleaseLocks(self.lu, locking.LEVEL_NODE_ALLOC)
+      # Only perform this test if a new CPU mask is given
+      if constants.HV_CPU_MASK in self.hv_new:
+        # Calculate the largest CPU number requested
+        max_requested_cpu = max(map(max, cpu_list))
+        # Check that all of the instance's nodes have enough physical CPUs to
+        # satisfy the requested CPU mask
+        _CheckNodesPhysicalCPUs(self, instance.all_nodes,
+                                max_requested_cpu + 1, instance.hypervisor)
 
+    # osparams processing
+    if self.op.osparams:
+      i_osdict = GetUpdatedParams(instance.osparams, self.op.osparams)
+      CheckOSParams(self, True, nodelist, instance_os, i_osdict)
+      self.os_inst = i_osdict # the new dict (without defaults)
     else:
-      assert not self.lu.glm.is_owned(locking.LEVEL_NODE_ALLOC)
-
-      secondary_nodes = instance.secondary_nodes
-      if not secondary_nodes:
-        raise errors.ConfigurationError("No secondary node but using"
-                                        " %s disk template" %
-                                        instance.disk_template)
-      target_node = secondary_nodes[0]
-      if self.lu.op.iallocator or (self.lu.op.target_node and
-                                   self.lu.op.target_node != target_node):
-        if self.failover:
-          text = "failed over"
-        else:
-          text = "migrated"
-        raise errors.OpPrereqError("Instances with disk template %s cannot"
-                                   " be %s to arbitrary nodes"
-                                   " (neither an iallocator nor a target"
-                                   " node can be passed)" %
-                                   (instance.disk_template, text),
-                                   errors.ECODE_INVAL)
-      nodeinfo = self.cfg.GetNodeInfo(target_node)
-      group_info = self.cfg.GetNodeGroup(nodeinfo.group)
-      ipolicy = ganeti.masterd.instance.CalculateGroupIPolicy(cluster,
-                                                              group_info)
-      _CheckTargetNodeIPolicy(self.lu, ipolicy, instance, nodeinfo, self.cfg,
-                              ignore=self.ignore_ipolicy)
-
-    i_be = cluster.FillBE(instance)
-
-    # check memory requirements on the secondary node
-    if (not self.cleanup and
-         (not self.failover or instance.admin_state == constants.ADMINST_UP)):
-      self.tgt_free_mem = _CheckNodeFreeMemory(self.lu, target_node,
-                                               "migrating instance %s" %
-                                               instance.name,
-                                               i_be[constants.BE_MINMEM],
-                                               instance.hypervisor)
-    else:
-      self.lu.LogInfo("Not checking memory on the secondary node as"
-                      " instance will not be started")
-
-    # check if failover must be forced instead of migration
-    if (not self.cleanup and not self.failover and
-        i_be[constants.BE_ALWAYS_FAILOVER]):
-      self.lu.LogInfo("Instance configured to always failover; fallback"
-                      " to failover")
-      self.failover = True
+      self.os_inst = {}
 
-    # check bridge existance
-    _CheckInstanceBridgesExist(self.lu, instance, node=target_node)
-
-    if not self.cleanup:
-      _CheckNodeNotDrained(self.lu, target_node)
-      if not self.failover:
-        result = self.rpc.call_instance_migratable(instance.primary_node,
-                                                   instance)
-        if result.fail_msg and self.fallback:
-          self.lu.LogInfo("Can't migrate, instance offline, fallback to"
-                          " failover")
-          self.failover = True
+    #TODO(dynmem): do the appropriate check involving MINMEM
+    if (constants.BE_MAXMEM in self.op.beparams and not self.op.force and
+        be_new[constants.BE_MAXMEM] > be_old[constants.BE_MAXMEM]):
+      mem_check_list = [pnode]
+      if be_new[constants.BE_AUTO_BALANCE]:
+        # either we changed auto_balance to yes or it was from before
+        mem_check_list.extend(instance.secondary_nodes)
+      instance_info = self.rpc.call_instance_info(pnode, instance.name,
+                                                  instance.hypervisor)
+      nodeinfo = self.rpc.call_node_info(mem_check_list, None,
+                                         [instance.hypervisor], False)
+      pninfo = nodeinfo[pnode]
+      msg = pninfo.fail_msg
+      if msg:
+        # Assume the primary node is unreachable and go ahead
+        self.warn.append("Can't get info from primary node %s: %s" %
+                         (pnode, msg))
+      else:
+        (_, _, (pnhvinfo, )) = pninfo.payload
+        if not isinstance(pnhvinfo.get("memory_free", None), int):
+          self.warn.append("Node data from primary node %s doesn't contain"
+                           " free memory information" % pnode)
+        elif instance_info.fail_msg:
+          self.warn.append("Can't get instance runtime information: %s" %
+                           instance_info.fail_msg)
         else:
-          result.Raise("Can't migrate, please use failover",
-                       prereq=True, ecode=errors.ECODE_STATE)
-
-    assert not (self.failover and self.cleanup)
+          if instance_info.payload:
+            current_mem = int(instance_info.payload["memory"])
+          else:
+            # Assume instance not running
+            # (there is a slight race condition here, but it's not very
+            # probable, and we have no other way to check)
+            # TODO: Describe race condition
+            current_mem = 0
+          #TODO(dynmem): do the appropriate check involving MINMEM
+          miss_mem = (be_new[constants.BE_MAXMEM] - current_mem -
+                      pnhvinfo["memory_free"])
+          if miss_mem > 0:
+            raise errors.OpPrereqError("This change will prevent the instance"
+                                       " from starting, due to %d MB of memory"
+                                       " missing on its primary node" %
+                                       miss_mem, errors.ECODE_NORES)
 
-    if not self.failover:
-      if self.lu.op.live is not None and self.lu.op.mode is not None:
-        raise errors.OpPrereqError("Only one of the 'live' and 'mode'"
-                                   " parameters are accepted",
-                                   errors.ECODE_INVAL)
-      if self.lu.op.live is not None:
-        if self.lu.op.live:
-          self.lu.op.mode = constants.HT_MIGRATION_LIVE
-        else:
-          self.lu.op.mode = constants.HT_MIGRATION_NONLIVE
-        # reset the 'live' parameter to None so that repeated
-        # invocations of CheckPrereq do not raise an exception
-        self.lu.op.live = None
-      elif self.lu.op.mode is None:
-        # read the default value from the hypervisor
-        i_hv = cluster.FillHV(self.instance, skip_globals=False)
-        self.lu.op.mode = i_hv[constants.HV_MIGRATION_MODE]
-
-      self.live = self.lu.op.mode == constants.HT_MIGRATION_LIVE
-    else:
-      # Failover is never live
-      self.live = False
+      if be_new[constants.BE_AUTO_BALANCE]:
+        for node, nres in nodeinfo.items():
+          if node not in instance.secondary_nodes:
+            continue
+          nres.Raise("Can't get info from secondary node %s" % node,
+                     prereq=True, ecode=errors.ECODE_STATE)
+          (_, _, (nhvinfo, )) = nres.payload
+          if not isinstance(nhvinfo.get("memory_free", None), int):
+            raise errors.OpPrereqError("Secondary node %s didn't return free"
+                                       " memory information" % node,
+                                       errors.ECODE_STATE)
+          #TODO(dynmem): do the appropriate check involving MINMEM
+          elif be_new[constants.BE_MAXMEM] > nhvinfo["memory_free"]:
+            raise errors.OpPrereqError("This change will prevent the instance"
+                                       " from failover to its secondary node"
+                                       " %s, due to not enough memory" % node,
+                                       errors.ECODE_STATE)
 
-    if not (self.failover or self.cleanup):
+    if self.op.runtime_mem:
       remote_info = self.rpc.call_instance_info(instance.primary_node,
                                                 instance.name,
                                                 instance.hypervisor)
-      remote_info.Raise("Error checking instance on node %s" %
-                        instance.primary_node)
-      instance_running = bool(remote_info.payload)
-      if instance_running:
-        self.current_mem = int(remote_info.payload["memory"])
-
-  def _RunAllocator(self):
-    """Run the allocator based on input opcode.
-
-    """
-    assert locking.NAL in self.lu.owned_locks(locking.LEVEL_NODE_ALLOC)
-
-    # FIXME: add a self.ignore_ipolicy option
-    req = iallocator.IAReqRelocate(name=self.instance_name,
-                                   relocate_from=[self.instance.primary_node])
-    ial = iallocator.IAllocator(self.cfg, self.rpc, req)
-
-    ial.Run(self.lu.op.iallocator)
-
-    if not ial.success:
-      raise errors.OpPrereqError("Can't compute nodes using"
-                                 " iallocator '%s': %s" %
-                                 (self.lu.op.iallocator, ial.info),
-                                 errors.ECODE_NORES)
-    self.target_node = ial.result[0]
-    self.lu.LogInfo("Selected nodes for instance %s via iallocator %s: %s",
-                    self.instance_name, self.lu.op.iallocator,
-                    utils.CommaJoin(ial.result))
+      remote_info.Raise("Error checking node %s" % instance.primary_node)
+      if not remote_info.payload: # not running already
+        raise errors.OpPrereqError("Instance %s is not running" %
+                                   instance.name, errors.ECODE_STATE)
 
-  def _WaitUntilSync(self):
-    """Poll with custom rpc for disk sync.
+      current_memory = remote_info.payload["memory"]
+      if (not self.op.force and
+           (self.op.runtime_mem > self.be_proposed[constants.BE_MAXMEM] or
+            self.op.runtime_mem < self.be_proposed[constants.BE_MINMEM])):
+        raise errors.OpPrereqError("Instance %s must have memory between %d"
+                                   " and %d MB of memory unless --force is"
+                                   " given" %
+                                   (instance.name,
+                                    self.be_proposed[constants.BE_MINMEM],
+                                    self.be_proposed[constants.BE_MAXMEM]),
+                                   errors.ECODE_INVAL)
 
-    This uses our own step-based rpc call.
+      delta = self.op.runtime_mem - current_memory
+      if delta > 0:
+        CheckNodeFreeMemory(self, instance.primary_node,
+                            "ballooning memory for instance %s" %
+                            instance.name, delta, instance.hypervisor)
 
-    """
-    self.feedback_fn("* wait until resync is done")
-    all_done = False
-    while not all_done:
-      all_done = True
-      result = self.rpc.call_drbd_wait_sync(self.all_nodes,
-                                            self.nodes_ip,
-                                            (self.instance.disks,
-                                             self.instance))
-      min_percent = 100
-      for node, nres in result.items():
-        nres.Raise("Cannot resync disks on node %s" % node)
-        node_done, node_percent = nres.payload
-        all_done = all_done and node_done
-        if node_percent is not None:
-          min_percent = min(min_percent, node_percent)
-      if not all_done:
-        if min_percent < 100:
-          self.feedback_fn("   - progress: %.1f%%" % min_percent)
-        time.sleep(2)
-
-  def _EnsureSecondary(self, node):
-    """Demote a node to secondary.
+    if self.op.disks and instance.disk_template == constants.DT_DISKLESS:
+      raise errors.OpPrereqError("Disk operations not supported for"
+                                 " diskless instances", errors.ECODE_INVAL)
 
-    """
-    self.feedback_fn("* switching node %s to secondary mode" % node)
+    def _PrepareNicCreate(_, params, private):
+      self._PrepareNicModification(params, private, None, None,
+                                   {}, cluster, pnode)
+      return (None, None)
 
-    for dev in self.instance.disks:
-      self.cfg.SetDiskID(dev, node)
+    def _PrepareNicMod(_, nic, params, private):
+      self._PrepareNicModification(params, private, nic.ip, nic.network,
+                                   nic.nicparams, cluster, pnode)
+      return None
 
-    result = self.rpc.call_blockdev_close(node, self.instance.name,
-                                          self.instance.disks)
-    result.Raise("Cannot change disk to secondary on node %s" % node)
+    def _PrepareNicRemove(_, params, __):
+      ip = params.ip
+      net = params.network
+      if net is not None and ip is not None:
+        self.cfg.ReleaseIp(net, ip, self.proc.GetECId())
 
-  def _GoStandalone(self):
-    """Disconnect from the network.
+    # Verify NIC changes (operating on copy)
+    nics = instance.nics[:]
+    _ApplyContainerMods("NIC", nics, None, self.nicmod,
+                        _PrepareNicCreate, _PrepareNicMod, _PrepareNicRemove)
+    if len(nics) > constants.MAX_NICS:
+      raise errors.OpPrereqError("Instance has too many network interfaces"
+                                 " (%d), cannot add more" % constants.MAX_NICS,
+                                 errors.ECODE_STATE)
 
-    """
-    self.feedback_fn("* changing into standalone mode")
-    result = self.rpc.call_drbd_disconnect_net(self.all_nodes, self.nodes_ip,
-                                               self.instance.disks)
-    for node, nres in result.items():
-      nres.Raise("Cannot disconnect disks node %s" % node)
+    def _PrepareDiskMod(_, disk, params, __):
+      disk.name = params.get(constants.IDISK_NAME, None)
 
-  def _GoReconnect(self, multimaster):
-    """Reconnect to the network.
+    # Verify disk changes (operating on a copy)
+    disks = copy.deepcopy(instance.disks)
+    _ApplyContainerMods("disk", disks, None, self.diskmod, None,
+                        _PrepareDiskMod, None)
+    utils.ValidateDeviceNames("disk", disks)
+    if len(disks) > constants.MAX_DISKS:
+      raise errors.OpPrereqError("Instance has too many disks (%d), cannot add"
+                                 " more" % constants.MAX_DISKS,
+                                 errors.ECODE_STATE)
+    disk_sizes = [disk.size for disk in instance.disks]
+    disk_sizes.extend(params["size"] for (op, idx, params, private) in
+                      self.diskmod if op == constants.DDM_ADD)
+    ispec[constants.ISPEC_DISK_COUNT] = len(disk_sizes)
+    ispec[constants.ISPEC_DISK_SIZE] = disk_sizes
 
-    """
-    if multimaster:
-      msg = "dual-master"
-    else:
-      msg = "single-master"
-    self.feedback_fn("* changing disks into %s mode" % msg)
-    result = self.rpc.call_drbd_attach_net(self.all_nodes, self.nodes_ip,
-                                           (self.instance.disks, self.instance),
-                                           self.instance.name, multimaster)
-    for node, nres in result.items():
-      nres.Raise("Cannot change disks config on node %s" % node)
-
-  def _ExecCleanup(self):
-    """Try to cleanup after a failed migration.
-
-    The cleanup is done by:
-      - check that the instance is running only on one node
-        (and update the config if needed)
-      - change disks on its secondary node to secondary
-      - wait until disks are fully synchronized
-      - disconnect from the network
-      - change disks into single-master mode
-      - wait again until disks are fully synchronized
+    if self.op.offline is not None and self.op.offline:
+      CheckInstanceState(self, instance, CAN_CHANGE_INSTANCE_OFFLINE,
+                         msg="can't change to offline")
 
-    """
-    instance = self.instance
-    target_node = self.target_node
-    source_node = self.source_node
-
-    # check running on only one node
-    self.feedback_fn("* checking where the instance actually runs"
-                     " (if this hangs, the hypervisor might be in"
-                     " a bad state)")
-    ins_l = self.rpc.call_instance_list(self.all_nodes, [instance.hypervisor])
-    for node, result in ins_l.items():
-      result.Raise("Can't contact node %s" % node)
-
-    runningon_source = instance.name in ins_l[source_node].payload
-    runningon_target = instance.name in ins_l[target_node].payload
-
-    if runningon_source and runningon_target:
-      raise errors.OpExecError("Instance seems to be running on two nodes,"
-                               " or the hypervisor is confused; you will have"
-                               " to ensure manually that it runs only on one"
-                               " and restart this operation")
-
-    if not (runningon_source or runningon_target):
-      raise errors.OpExecError("Instance does not seem to be running at all;"
-                               " in this case it's safer to repair by"
-                               " running 'gnt-instance stop' to ensure disk"
-                               " shutdown, and then restarting it")
-
-    if runningon_target:
-      # the migration has actually succeeded, we need to update the config
-      self.feedback_fn("* instance running on secondary node (%s),"
-                       " updating config" % target_node)
-      instance.primary_node = target_node
-      self.cfg.Update(instance, self.feedback_fn)
-      demoted_node = source_node
+    # Pre-compute NIC changes (necessary to use result in hooks)
+    self._nic_chgdesc = []
+    if self.nicmod:
+      # Operate on copies as this is still in prereq
+      nics = [nic.Copy() for nic in instance.nics]
+      _ApplyContainerMods("NIC", nics, self._nic_chgdesc, self.nicmod,
+                          self._CreateNewNic, self._ApplyNicMods, None)
+      # Verify that NIC names are unique and valid
+      utils.ValidateDeviceNames("NIC", nics)
+      self._new_nics = nics
+      ispec[constants.ISPEC_NIC_COUNT] = len(self._new_nics)
     else:
-      self.feedback_fn("* instance confirmed to be running on its"
-                       " primary node (%s)" % source_node)
-      demoted_node = target_node
-
-    if instance.disk_template in constants.DTS_INT_MIRROR:
-      self._EnsureSecondary(demoted_node)
-      try:
-        self._WaitUntilSync()
-      except errors.OpExecError:
-        # we ignore here errors, since if the device is standalone, it
-        # won't be able to sync
-        pass
-      self._GoStandalone()
-      self._GoReconnect(False)
-      self._WaitUntilSync()
+      self._new_nics = None
+      ispec[constants.ISPEC_NIC_COUNT] = len(instance.nics)
 
-    self.feedback_fn("* done")
+    if not self.op.ignore_ipolicy:
+      ipolicy = ganeti.masterd.instance.CalculateGroupIPolicy(cluster,
+                                                              group_info)
 
-  def _RevertDiskStatus(self):
-    """Try to revert the disk status after a failed migration.
+      # Fill ispec with backend parameters
+      ispec[constants.ISPEC_SPINDLE_USE] = \
+        self.be_new.get(constants.BE_SPINDLE_USE, None)
+      ispec[constants.ISPEC_CPU_COUNT] = self.be_new.get(constants.BE_VCPUS,
+                                                         None)
 
-    """
-    target_node = self.target_node
-    if self.instance.disk_template in constants.DTS_EXT_MIRROR:
-      return
+      # Copy ispec to verify parameters with min/max values separately
+      if self.op.disk_template:
+        new_disk_template = self.op.disk_template
+      else:
+        new_disk_template = instance.disk_template
+      ispec_max = ispec.copy()
+      ispec_max[constants.ISPEC_MEM_SIZE] = \
+        self.be_new.get(constants.BE_MAXMEM, None)
+      res_max = _ComputeIPolicyInstanceSpecViolation(ipolicy, ispec_max,
+                                                     new_disk_template)
+      ispec_min = ispec.copy()
+      ispec_min[constants.ISPEC_MEM_SIZE] = \
+        self.be_new.get(constants.BE_MINMEM, None)
+      res_min = _ComputeIPolicyInstanceSpecViolation(ipolicy, ispec_min,
+                                                     new_disk_template)
 
-    try:
-      self._EnsureSecondary(target_node)
-      self._GoStandalone()
-      self._GoReconnect(False)
-      self._WaitUntilSync()
-    except errors.OpExecError, err:
-      self.lu.LogWarning("Migration failed and I can't reconnect the drives,"
-                         " please try to recover the instance manually;"
-                         " error '%s'" % str(err))
-
-  def _AbortMigration(self):
-    """Call the hypervisor code to abort a started migration.
+      if (res_max or res_min):
+        # FIXME: Improve error message by including information about whether
+        # the upper or lower limit of the parameter fails the ipolicy.
+        msg = ("Instance allocation to group %s (%s) violates policy: %s" %
+               (group_info, group_info.name,
+                utils.CommaJoin(set(res_max + res_min))))
+        raise errors.OpPrereqError(msg, errors.ECODE_INVAL)
 
-    """
-    instance = self.instance
-    target_node = self.target_node
-    source_node = self.source_node
-    migration_info = self.migration_info
-
-    abort_result = self.rpc.call_instance_finalize_migration_dst(target_node,
-                                                                 instance,
-                                                                 migration_info,
-                                                                 False)
-    abort_msg = abort_result.fail_msg
-    if abort_msg:
-      logging.error("Aborting migration failed on target node %s: %s",
-                    target_node, abort_msg)
-      # Don't raise an exception here, as we stil have to try to revert the
-      # disk status, even if this step failed.
-
-    abort_result = self.rpc.call_instance_finalize_migration_src(
-      source_node, instance, False, self.live)
-    abort_msg = abort_result.fail_msg
-    if abort_msg:
-      logging.error("Aborting migration failed on source node %s: %s",
-                    source_node, abort_msg)
-
-  def _ExecMigration(self):
-    """Migrate an instance.
-
-    The migrate is done by:
-      - change the disks into dual-master mode
-      - wait until disks are fully synchronized again
-      - migrate the instance
-      - change disks on the new secondary node (the old primary) to secondary
-      - wait until disks are fully synchronized
-      - change disks into single-master mode
+  def _ConvertPlainToDrbd(self, feedback_fn):
+    """Converts an instance from plain to drbd.
 
     """
+    feedback_fn("Converting template to drbd")
     instance = self.instance
-    target_node = self.target_node
-    source_node = self.source_node
-
-    # Check for hypervisor version mismatch and warn the user.
-    nodeinfo = self.rpc.call_node_info([source_node, target_node],
-                                       None, [self.instance.hypervisor], False)
-    for ninfo in nodeinfo.values():
-      ninfo.Raise("Unable to retrieve node information from node '%s'" %
-                  ninfo.node)
-    (_, _, (src_info, )) = nodeinfo[source_node].payload
-    (_, _, (dst_info, )) = nodeinfo[target_node].payload
-
-    if ((constants.HV_NODEINFO_KEY_VERSION in src_info) and
-        (constants.HV_NODEINFO_KEY_VERSION in dst_info)):
-      src_version = src_info[constants.HV_NODEINFO_KEY_VERSION]
-      dst_version = dst_info[constants.HV_NODEINFO_KEY_VERSION]
-      if src_version != dst_version:
-        self.feedback_fn("* warning: hypervisor version mismatch between"
-                         " source (%s) and target (%s) node" %
-                         (src_version, dst_version))
-
-    self.feedback_fn("* checking disk consistency between source and target")
-    for (idx, dev) in enumerate(instance.disks):
-      if not _CheckDiskConsistency(self.lu, instance, dev, target_node, False):
-        raise errors.OpExecError("Disk %s is degraded or not fully"
-                                 " synchronized on target node,"
-                                 " aborting migration" % idx)
-
-    if self.current_mem > self.tgt_free_mem:
-      if not self.allow_runtime_changes:
-        raise errors.OpExecError("Memory ballooning not allowed and not enough"
-                                 " free memory to fit instance %s on target"
-                                 " node %s (have %dMB, need %dMB)" %
-                                 (instance.name, target_node,
-                                  self.tgt_free_mem, self.current_mem))
-      self.feedback_fn("* setting instance memory to %s" % self.tgt_free_mem)
-      rpcres = self.rpc.call_instance_balloon_memory(instance.primary_node,
-                                                     instance,
-                                                     self.tgt_free_mem)
-      rpcres.Raise("Cannot modify instance runtime memory")
+    pnode = instance.primary_node
+    snode = self.op.remote_node
 
-    # First get the migration information from the remote node
-    result = self.rpc.call_migration_info(source_node, instance)
-    msg = result.fail_msg
-    if msg:
-      log_err = ("Failed fetching source migration information from %s: %s" %
-                 (source_node, msg))
-      logging.error(log_err)
-      raise errors.OpExecError(log_err)
-
-    self.migration_info = migration_info = result.payload
-
-    if self.instance.disk_template not in constants.DTS_EXT_MIRROR:
-      # Then switch the disks to master/master mode
-      self._EnsureSecondary(target_node)
-      self._GoStandalone()
-      self._GoReconnect(True)
-      self._WaitUntilSync()
-
-    self.feedback_fn("* preparing %s to accept the instance" % target_node)
-    result = self.rpc.call_accept_instance(target_node,
-                                           instance,
-                                           migration_info,
-                                           self.nodes_ip[target_node])
+    assert instance.disk_template == constants.DT_PLAIN
 
-    msg = result.fail_msg
-    if msg:
-      logging.error("Instance pre-migration failed, trying to revert"
-                    " disk status: %s", msg)
-      self.feedback_fn("Pre-migration failed, aborting")
-      self._AbortMigration()
-      self._RevertDiskStatus()
-      raise errors.OpExecError("Could not pre-migrate instance %s: %s" %
-                               (instance.name, msg))
-
-    self.feedback_fn("* migrating instance to %s" % target_node)
-    result = self.rpc.call_instance_migrate(source_node, instance,
-                                            self.nodes_ip[target_node],
-                                            self.live)
-    msg = result.fail_msg
-    if msg:
-      logging.error("Instance migration failed, trying to revert"
-                    " disk status: %s", msg)
-      self.feedback_fn("Migration failed, aborting")
-      self._AbortMigration()
-      self._RevertDiskStatus()
-      raise errors.OpExecError("Could not migrate instance %s: %s" %
-                               (instance.name, msg))
-
-    self.feedback_fn("* starting memory transfer")
-    last_feedback = time.time()
-    while True:
-      result = self.rpc.call_instance_get_migration_status(source_node,
-                                                           instance)
-      msg = result.fail_msg
-      ms = result.payload   # MigrationStatus instance
-      if msg or (ms.status in constants.HV_MIGRATION_FAILED_STATUSES):
-        logging.error("Instance migration failed, trying to revert"
-                      " disk status: %s", msg)
-        self.feedback_fn("Migration failed, aborting")
-        self._AbortMigration()
-        self._RevertDiskStatus()
-        if not msg:
-          msg = "hypervisor returned failure"
-        raise errors.OpExecError("Could not migrate instance %s: %s" %
-                                 (instance.name, msg))
-
-      if result.payload.status != constants.HV_MIGRATION_ACTIVE:
-        self.feedback_fn("* memory transfer complete")
-        break
+    # create a fake disk info for _GenerateDiskTemplate
+    disk_info = [{constants.IDISK_SIZE: d.size, constants.IDISK_MODE: d.mode,
+                  constants.IDISK_VG: d.logical_id[0],
+                  constants.IDISK_NAME: d.name}
+                 for d in instance.disks]
+    new_disks = GenerateDiskTemplate(self, self.op.disk_template,
+                                     instance.name, pnode, [snode],
+                                     disk_info, None, None, 0, feedback_fn,
+                                     self.diskparams)
+    anno_disks = rpc.AnnotateDiskParams(constants.DT_DRBD8, new_disks,
+                                        self.diskparams)
+    p_excl_stor = IsExclusiveStorageEnabledNodeName(self.cfg, pnode)
+    s_excl_stor = IsExclusiveStorageEnabledNodeName(self.cfg, snode)
+    info = GetInstanceInfoText(instance)
+    feedback_fn("Creating additional volumes...")
+    # first, create the missing data and meta devices
+    for disk in anno_disks:
+      # unfortunately this is... not too nice
+      CreateSingleBlockDev(self, pnode, instance, disk.children[1],
+                           info, True, p_excl_stor)
+      for child in disk.children:
+        CreateSingleBlockDev(self, snode, instance, child, info, True,
+                             s_excl_stor)
+    # at this stage, all new LVs have been created, we can rename the
+    # old ones
+    feedback_fn("Renaming original volumes...")
+    rename_list = [(o, n.children[0].logical_id)
+                   for (o, n) in zip(instance.disks, new_disks)]
+    result = self.rpc.call_blockdev_rename(pnode, rename_list)
+    result.Raise("Failed to rename original LVs")
 
-      if (utils.TimeoutExpired(last_feedback,
-                               self._MIGRATION_FEEDBACK_INTERVAL) and
-          ms.transferred_ram is not None):
-        mem_progress = 100 * float(ms.transferred_ram) / float(ms.total_ram)
-        self.feedback_fn("* memory transfer progress: %.2f %%" % mem_progress)
-        last_feedback = time.time()
+    feedback_fn("Initializing DRBD devices...")
+    # all child devices are in place, we can now create the DRBD devices
+    try:
+      for disk in anno_disks:
+        for (node, excl_stor) in [(pnode, p_excl_stor), (snode, s_excl_stor)]:
+          f_create = node == pnode
+          CreateSingleBlockDev(self, node, instance, disk, info, f_create,
+                               excl_stor)
+    except errors.GenericError, e:
+      feedback_fn("Initializing of DRBD devices failed;"
+                  " renaming back original volumes...")
+      for disk in new_disks:
+        self.cfg.SetDiskID(disk, pnode)
+      rename_back_list = [(n.children[0], o.logical_id)
+                          for (n, o) in zip(new_disks, instance.disks)]
+      result = self.rpc.call_blockdev_rename(pnode, rename_back_list)
+      result.Raise("Failed to rename LVs back after error %s" % str(e))
+      raise
 
-      time.sleep(self._MIGRATION_POLL_INTERVAL)
+    # at this point, the instance has been modified
+    instance.disk_template = constants.DT_DRBD8
+    instance.disks = new_disks
+    self.cfg.Update(instance, feedback_fn)
 
-    result = self.rpc.call_instance_finalize_migration_src(source_node,
-                                                           instance,
-                                                           True,
-                                                           self.live)
-    msg = result.fail_msg
-    if msg:
-      logging.error("Instance migration succeeded, but finalization failed"
-                    " on the source node: %s", msg)
-      raise errors.OpExecError("Could not finalize instance migration: %s" %
-                               msg)
+    # Release node locks while waiting for sync
+    ReleaseLocks(self, locking.LEVEL_NODE)
 
-    instance.primary_node = target_node
+    # disks are created, waiting for sync
+    disk_abort = not WaitForSync(self, instance,
+                                 oneshot=not self.op.wait_for_sync)
+    if disk_abort:
+      raise errors.OpExecError("There are some degraded disks for"
+                               " this instance, please cleanup manually")
 
-    # distribute new instance config to the other nodes
-    self.cfg.Update(instance, self.feedback_fn)
+    # Node resource locks will be released by caller
 
-    result = self.rpc.call_instance_finalize_migration_dst(target_node,
-                                                           instance,
-                                                           migration_info,
-                                                           True)
-    msg = result.fail_msg
-    if msg:
-      logging.error("Instance migration succeeded, but finalization failed"
-                    " on the target node: %s", msg)
-      raise errors.OpExecError("Could not finalize instance migration: %s" %
-                               msg)
-
-    if self.instance.disk_template not in constants.DTS_EXT_MIRROR:
-      self._EnsureSecondary(source_node)
-      self._WaitUntilSync()
-      self._GoStandalone()
-      self._GoReconnect(False)
-      self._WaitUntilSync()
-
-    # If the instance's disk template is `rbd' or `ext' and there was a
-    # successful migration, unmap the device from the source node.
-    if self.instance.disk_template in (constants.DT_RBD, constants.DT_EXT):
-      disks = _ExpandCheckDisks(instance, instance.disks)
-      self.feedback_fn("* unmapping instance's disks from %s" % source_node)
-      for disk in disks:
-        result = self.rpc.call_blockdev_shutdown(source_node, (disk, instance))
-        msg = result.fail_msg
-        if msg:
-          logging.error("Migration was successful, but couldn't unmap the"
-                        " block device %s on source node %s: %s",
-                        disk.iv_name, source_node, msg)
-          logging.error("You need to unmap the device %s manually on %s",
-                        disk.iv_name, source_node)
-
-    self.feedback_fn("* done")
-
-  def _ExecFailover(self):
-    """Failover an instance.
-
-    The failover is done by shutting it down on its present node and
-    starting it on the secondary.
+  def _ConvertDrbdToPlain(self, feedback_fn):
+    """Converts an instance from drbd to plain.
 
     """
     instance = self.instance
-    primary_node = self.cfg.GetNodeInfo(instance.primary_node)
 
-    source_node = instance.primary_node
-    target_node = self.target_node
+    assert len(instance.secondary_nodes) == 1
+    assert instance.disk_template == constants.DT_DRBD8
 
-    if instance.admin_state == constants.ADMINST_UP:
-      self.feedback_fn("* checking disk consistency between source and target")
-      for (idx, dev) in enumerate(instance.disks):
-        # for drbd, these are drbd over lvm
-        if not _CheckDiskConsistency(self.lu, instance, dev, target_node,
-                                     False):
-          if primary_node.offline:
-            self.feedback_fn("Node %s is offline, ignoring degraded disk %s on"
-                             " target node %s" %
-                             (primary_node.name, idx, target_node))
-          elif not self.ignore_consistency:
-            raise errors.OpExecError("Disk %s is degraded on target node,"
-                                     " aborting failover" % idx)
-    else:
-      self.feedback_fn("* not checking disk consistency as instance is not"
-                       " running")
+    pnode = instance.primary_node
+    snode = instance.secondary_nodes[0]
+    feedback_fn("Converting template to plain")
 
-    self.feedback_fn("* shutting down instance on source node")
-    logging.info("Shutting down instance %s on node %s",
-                 instance.name, source_node)
+    old_disks = AnnotateDiskParams(instance, instance.disks, self.cfg)
+    new_disks = [d.children[0] for d in instance.disks]
 
-    result = self.rpc.call_instance_shutdown(source_node, instance,
-                                             self.shutdown_timeout,
-                                             self.lu.op.reason)
-    msg = result.fail_msg
-    if msg:
-      if self.ignore_consistency or primary_node.offline:
-        self.lu.LogWarning("Could not shutdown instance %s on node %s,"
-                           " proceeding anyway; please make sure node"
-                           " %s is down; error details: %s",
-                           instance.name, source_node, source_node, msg)
-      else:
-        raise errors.OpExecError("Could not shutdown instance %s on"
-                                 " node %s: %s" %
-                                 (instance.name, source_node, msg))
+    # copy over size, mode and name
+    for parent, child in zip(old_disks, new_disks):
+      child.size = parent.size
+      child.mode = parent.mode
+      child.name = parent.name
 
-    self.feedback_fn("* deactivating the instance's disks on source node")
-    if not _ShutdownInstanceDisks(self.lu, instance, ignore_primary=True):
-      raise errors.OpExecError("Can't shut down the instance's disks")
+    # this is a DRBD disk, return its port to the pool
+    # NOTE: this must be done right before the call to cfg.Update!
+    for disk in old_disks:
+      tcp_port = disk.logical_id[2]
+      self.cfg.AddTcpUdpPort(tcp_port)
 
-    instance.primary_node = target_node
-    # distribute new instance config to the other nodes
-    self.cfg.Update(instance, self.feedback_fn)
+    # update instance structure
+    instance.disks = new_disks
+    instance.disk_template = constants.DT_PLAIN
+    _UpdateIvNames(0, instance.disks)
+    self.cfg.Update(instance, feedback_fn)
 
-    # Only start the instance if it's marked as up
-    if instance.admin_state == constants.ADMINST_UP:
-      self.feedback_fn("* activating the instance's disks on target node %s" %
-                       target_node)
-      logging.info("Starting instance %s on node %s",
-                   instance.name, target_node)
+    # Release locks in case removing disks takes a while
+    ReleaseLocks(self, locking.LEVEL_NODE)
 
-      disks_ok, _ = _AssembleInstanceDisks(self.lu, instance,
-                                           ignore_secondaries=True)
-      if not disks_ok:
-        _ShutdownInstanceDisks(self.lu, instance)
-        raise errors.OpExecError("Can't activate the instance's disks")
+    feedback_fn("Removing volumes on the secondary node...")
+    for disk in old_disks:
+      self.cfg.SetDiskID(disk, snode)
+      msg = self.rpc.call_blockdev_remove(snode, disk).fail_msg
+      if msg:
+        self.LogWarning("Could not remove block device %s on node %s,"
+                        " continuing anyway: %s", disk.iv_name, snode, msg)
 
-      self.feedback_fn("* starting the instance on the target node %s" %
-                       target_node)
-      result = self.rpc.call_instance_start(target_node, (instance, None, None),
-                                            False, self.lu.op.reason)
-      msg = result.fail_msg
+    feedback_fn("Removing unneeded volumes on the primary node...")
+    for idx, disk in enumerate(old_disks):
+      meta = disk.children[1]
+      self.cfg.SetDiskID(meta, pnode)
+      msg = self.rpc.call_blockdev_remove(pnode, meta).fail_msg
       if msg:
-        _ShutdownInstanceDisks(self.lu, instance)
-        raise errors.OpExecError("Could not start instance %s on node %s: %s" %
-                                 (instance.name, target_node, msg))
+        self.LogWarning("Could not remove metadata for disk %d on node %s,"
+                        " continuing anyway: %s", idx, pnode, msg)
 
-  def Exec(self, feedback_fn):
-    """Perform the migration.
+  def _CreateNewDisk(self, idx, params, _):
+    """Creates a new disk.
 
     """
-    self.feedback_fn = feedback_fn
-    self.source_node = self.instance.primary_node
-
-    # FIXME: if we implement migrate-to-any in DRBD, this needs fixing
-    if self.instance.disk_template in constants.DTS_INT_MIRROR:
-      self.target_node = self.instance.secondary_nodes[0]
-      # Otherwise self.target_node has been populated either
-      # directly, or through an iallocator.
-
-    self.all_nodes = [self.source_node, self.target_node]
-    self.nodes_ip = dict((name, node.secondary_ip) for (name, node)
-                         in self.cfg.GetMultiNodeInfo(self.all_nodes))
-
-    if self.failover:
-      feedback_fn("Failover instance %s" % self.instance.name)
-      self._ExecFailover()
-    else:
-      feedback_fn("Migrating instance %s" % self.instance.name)
-
-      if self.cleanup:
-        return self._ExecCleanup()
-      else:
-        return self._ExecMigration()
-
-
-def _BlockdevFind(lu, node, dev, instance):
-  """Wrapper around call_blockdev_find to annotate diskparams.
-
-  @param lu: A reference to the lu object
-  @param node: The node to call out
-  @param dev: The device to find
-  @param instance: The instance object the device belongs to
-  @returns The result of the rpc call
-
-  """
-  (disk,) = _AnnotateDiskParams(instance, [dev], lu.cfg)
-  return lu.rpc.call_blockdev_find(node, disk)
+    instance = self.instance
 
+    # add a new disk
+    if instance.disk_template in constants.DTS_FILEBASED:
+      (file_driver, file_path) = instance.disks[0].logical_id
+      file_path = os.path.dirname(file_path)
+    else:
+      file_driver = file_path = None
 
-class TLReplaceDisks(Tasklet):
-  """Replaces disks for an instance.
+    disk = \
+      GenerateDiskTemplate(self, instance.disk_template, instance.name,
+                           instance.primary_node, instance.secondary_nodes,
+                           [params], file_path, file_driver, idx,
+                           self.Log, self.diskparams)[0]
 
-  Note: Locking is not within the scope of this class.
+    new_disks = CreateDisks(self, instance, disks=[disk])
 
-  """
-  def __init__(self, lu, instance_name, mode, iallocator_name, remote_node,
-               disks, early_release, ignore_ipolicy):
-    """Initializes this class.
+    if self.cluster.prealloc_wipe_disks:
+      # Wipe new disk
+      WipeOrCleanupDisks(self, instance,
+                         disks=[(idx, disk, 0)],
+                         cleanup=new_disks)
 
-    """
-    Tasklet.__init__(self, lu)
-
-    # Parameters
-    self.instance_name = instance_name
-    self.mode = mode
-    self.iallocator_name = iallocator_name
-    self.remote_node = remote_node
-    self.disks = disks
-    self.early_release = early_release
-    self.ignore_ipolicy = ignore_ipolicy
-
-    # Runtime data
-    self.instance = None
-    self.new_node = None
-    self.target_node = None
-    self.other_node = None
-    self.remote_node_info = None
-    self.node_secondary_ip = None
+    return (disk, [
+      ("disk/%d" % idx, "add:size=%s,mode=%s" % (disk.size, disk.mode)),
+      ])
 
   @staticmethod
-  def _RunAllocator(lu, iallocator_name, instance_name, relocate_from):
-    """Compute a new secondary node using an IAllocator.
+  def _ModifyDisk(idx, disk, params, _):
+    """Modifies a disk.
 
     """
-    req = iallocator.IAReqRelocate(name=instance_name,
-                                   relocate_from=list(relocate_from))
-    ial = iallocator.IAllocator(lu.cfg, lu.rpc, req)
-
-    ial.Run(iallocator_name)
-
-    if not ial.success:
-      raise errors.OpPrereqError("Can't compute nodes using iallocator '%s':"
-                                 " %s" % (iallocator_name, ial.info),
-                                 errors.ECODE_NORES)
-
-    remote_node_name = ial.result[0]
+    changes = []
+    if constants.IDISK_MODE in params:
+      disk.mode = params.get(constants.IDISK_MODE)
+      changes.append(("disk.mode/%d" % idx, disk.mode))
 
-    lu.LogInfo("Selected new secondary for instance '%s': %s",
-               instance_name, remote_node_name)
+    if constants.IDISK_NAME in params:
+      disk.name = params.get(constants.IDISK_NAME)
+      changes.append(("disk.name/%d" % idx, disk.name))
 
-    return remote_node_name
+    return changes
 
-  def _FindFaultyDisks(self, node_name):
-    """Wrapper for L{_FindFaultyInstanceDisks}.
+  def _RemoveDisk(self, idx, root, _):
+    """Removes a disk.
 
     """
-    return _FindFaultyInstanceDisks(self.cfg, self.rpc, self.instance,
-                                    node_name, True)
+    (anno_disk,) = AnnotateDiskParams(self.instance, [root], self.cfg)
+    for node, disk in anno_disk.ComputeNodeTree(self.instance.primary_node):
+      self.cfg.SetDiskID(disk, node)
+      msg = self.rpc.call_blockdev_remove(node, disk).fail_msg
+      if msg:
+        self.LogWarning("Could not remove disk/%d on node '%s': %s,"
+                        " continuing anyway", idx, node, msg)
 
-  def _CheckDisksActivated(self, instance):
-    """Checks if the instance disks are activated.
+    # if this is a DRBD disk, return its port to the pool
+    if root.dev_type in constants.LDS_DRBD:
+      self.cfg.AddTcpUdpPort(root.logical_id[2])
 
-    @param instance: The instance to check disks
-    @return: True if they are activated, False otherwise
+  def _CreateNewNic(self, idx, params, private):
+    """Creates data structure for a new network interface.
 
     """
-    nodes = instance.all_nodes
-
-    for idx, dev in enumerate(instance.disks):
-      for node in nodes:
-        self.lu.LogInfo("Checking disk/%d on %s", idx, node)
-        self.cfg.SetDiskID(dev, node)
-
-        result = _BlockdevFind(self, node, dev, instance)
-
-        if result.offline:
-          continue
-        elif result.fail_msg or not result.payload:
-          return False
-
-    return True
-
-  def CheckPrereq(self):
-    """Check prerequisites.
+    mac = params[constants.INIC_MAC]
+    ip = params.get(constants.INIC_IP, None)
+    net = params.get(constants.INIC_NETWORK, None)
+    name = params.get(constants.INIC_NAME, None)
+    net_uuid = self.cfg.LookupNetwork(net)
+    #TODO: not private.filled?? can a nic have no nicparams??
+    nicparams = private.filled
+    nobj = objects.NIC(mac=mac, ip=ip, network=net_uuid, name=name,
+                       nicparams=nicparams)
+    nobj.uuid = self.cfg.GenerateUniqueID(self.proc.GetECId())
 
-    This checks that the instance is in the cluster.
+    return (nobj, [
+      ("nic.%d" % idx,
+       "add:mac=%s,ip=%s,mode=%s,link=%s,network=%s" %
+       (mac, ip, private.filled[constants.NIC_MODE],
+       private.filled[constants.NIC_LINK],
+       net)),
+      ])
+
+  def _ApplyNicMods(self, idx, nic, params, private):
+    """Modifies a network interface.
 
     """
-    self.instance = instance = self.cfg.GetInstanceInfo(self.instance_name)
-    assert instance is not None, \
-      "Cannot retrieve locked instance %s" % self.instance_name
+    changes = []
 
-    if instance.disk_template != constants.DT_DRBD8:
-      raise errors.OpPrereqError("Can only run replace disks for DRBD8-based"
-                                 " instances", errors.ECODE_INVAL)
+    for key in [constants.INIC_MAC, constants.INIC_IP, constants.INIC_NAME]:
+      if key in params:
+        changes.append(("nic.%s/%d" % (key, idx), params[key]))
+        setattr(nic, key, params[key])
 
-    if len(instance.secondary_nodes) != 1:
-      raise errors.OpPrereqError("The instance has a strange layout,"
-                                 " expected one secondary but found %d" %
-                                 len(instance.secondary_nodes),
-                                 errors.ECODE_FAULT)
+    new_net = params.get(constants.INIC_NETWORK, nic.network)
+    new_net_uuid = self.cfg.LookupNetwork(new_net)
+    if new_net_uuid != nic.network:
+      changes.append(("nic.network/%d" % idx, new_net))
+      nic.network = new_net_uuid
 
-    instance = self.instance
-    secondary_node = instance.secondary_nodes[0]
+    if private.filled:
+      nic.nicparams = private.filled
 
-    if self.iallocator_name is None:
-      remote_node = self.remote_node
-    else:
-      remote_node = self._RunAllocator(self.lu, self.iallocator_name,
-                                       instance.name, instance.secondary_nodes)
+      for (key, val) in nic.nicparams.items():
+        changes.append(("nic.%s/%d" % (key, idx), val))
 
-    if remote_node is None:
-      self.remote_node_info = None
-    else:
-      assert remote_node in self.lu.owned_locks(locking.LEVEL_NODE), \
-             "Remote node '%s' is not locked" % remote_node
+    return changes
 
-      self.remote_node_info = self.cfg.GetNodeInfo(remote_node)
-      assert self.remote_node_info is not None, \
-        "Cannot retrieve locked node %s" % remote_node
+  def Exec(self, feedback_fn):
+    """Modifies an instance.
 
-    if remote_node == self.instance.primary_node:
-      raise errors.OpPrereqError("The specified node is the primary node of"
-                                 " the instance", errors.ECODE_INVAL)
+    All parameters take effect only at the next restart of the instance.
 
-    if remote_node == secondary_node:
-      raise errors.OpPrereqError("The specified node is already the"
-                                 " secondary node of the instance",
-                                 errors.ECODE_INVAL)
+    """
+    # Process here the warnings from CheckPrereq, as we don't have a
+    # feedback_fn there.
+    # TODO: Replace with self.LogWarning
+    for warn in self.warn:
+      feedback_fn("WARNING: %s" % warn)
 
-    if self.disks and self.mode in (constants.REPLACE_DISK_AUTO,
-                                    constants.REPLACE_DISK_CHG):
-      raise errors.OpPrereqError("Cannot specify disks to be replaced",
-                                 errors.ECODE_INVAL)
+    assert ((self.op.disk_template is None) ^
+            bool(self.owned_locks(locking.LEVEL_NODE_RES))), \
+      "Not owning any node resource locks"
 
-    if self.mode == constants.REPLACE_DISK_AUTO:
-      if not self._CheckDisksActivated(instance):
-        raise errors.OpPrereqError("Please run activate-disks on instance %s"
-                                   " first" % self.instance_name,
-                                   errors.ECODE_STATE)
-      faulty_primary = self._FindFaultyDisks(instance.primary_node)
-      faulty_secondary = self._FindFaultyDisks(secondary_node)
+    result = []
+    instance = self.instance
 
-      if faulty_primary and faulty_secondary:
-        raise errors.OpPrereqError("Instance %s has faulty disks on more than"
-                                   " one node and can not be repaired"
-                                   " automatically" % self.instance_name,
-                                   errors.ECODE_STATE)
+    # New primary node
+    if self.op.pnode:
+      instance.primary_node = self.op.pnode
 
-      if faulty_primary:
-        self.disks = faulty_primary
-        self.target_node = instance.primary_node
-        self.other_node = secondary_node
-        check_nodes = [self.target_node, self.other_node]
-      elif faulty_secondary:
-        self.disks = faulty_secondary
-        self.target_node = secondary_node
-        self.other_node = instance.primary_node
-        check_nodes = [self.target_node, self.other_node]
-      else:
-        self.disks = []
-        check_nodes = []
+    # runtime memory
+    if self.op.runtime_mem:
+      rpcres = self.rpc.call_instance_balloon_memory(instance.primary_node,
+                                                     instance,
+                                                     self.op.runtime_mem)
+      rpcres.Raise("Cannot modify instance runtime memory")
+      result.append(("runtime_memory", self.op.runtime_mem))
 
-    else:
-      # Non-automatic modes
-      if self.mode == constants.REPLACE_DISK_PRI:
-        self.target_node = instance.primary_node
-        self.other_node = secondary_node
-        check_nodes = [self.target_node, self.other_node]
-
-      elif self.mode == constants.REPLACE_DISK_SEC:
-        self.target_node = secondary_node
-        self.other_node = instance.primary_node
-        check_nodes = [self.target_node, self.other_node]
-
-      elif self.mode == constants.REPLACE_DISK_CHG:
-        self.new_node = remote_node
-        self.other_node = instance.primary_node
-        self.target_node = secondary_node
-        check_nodes = [self.new_node, self.other_node]
-
-        _CheckNodeNotDrained(self.lu, remote_node)
-        _CheckNodeVmCapable(self.lu, remote_node)
-
-        old_node_info = self.cfg.GetNodeInfo(secondary_node)
-        assert old_node_info is not None
-        if old_node_info.offline and not self.early_release:
-          # doesn't make sense to delay the release
-          self.early_release = True
-          self.lu.LogInfo("Old secondary %s is offline, automatically enabling"
-                          " early-release mode", secondary_node)
+    # Apply disk changes
+    _ApplyContainerMods("disk", instance.disks, result, self.diskmod,
+                        self._CreateNewDisk, self._ModifyDisk,
+                        self._RemoveDisk)
+    _UpdateIvNames(0, instance.disks)
 
-      else:
-        raise errors.ProgrammerError("Unhandled disk replace mode (%s)" %
-                                     self.mode)
-
-      # If not specified all disks should be replaced
-      if not self.disks:
-        self.disks = range(len(self.instance.disks))
-
-    # TODO: This is ugly, but right now we can't distinguish between internal
-    # submitted opcode and external one. We should fix that.
-    if self.remote_node_info:
-      # We change the node, lets verify it still meets instance policy
-      new_group_info = self.cfg.GetNodeGroup(self.remote_node_info.group)
-      cluster = self.cfg.GetClusterInfo()
-      ipolicy = ganeti.masterd.instance.CalculateGroupIPolicy(cluster,
-                                                              new_group_info)
-      _CheckTargetNodeIPolicy(self, ipolicy, instance, self.remote_node_info,
-                              self.cfg, ignore=self.ignore_ipolicy)
+    if self.op.disk_template:
+      if __debug__:
+        check_nodes = set(instance.all_nodes)
+        if self.op.remote_node:
+          check_nodes.add(self.op.remote_node)
+        for level in [locking.LEVEL_NODE, locking.LEVEL_NODE_RES]:
+          owned = self.owned_locks(level)
+          assert not (check_nodes - owned), \
+            ("Not owning the correct locks, owning %r, expected at least %r" %
+             (owned, check_nodes))
 
-    for node in check_nodes:
-      _CheckNodeOnline(self.lu, node)
+      r_shut = ShutdownInstanceDisks(self, instance)
+      if not r_shut:
+        raise errors.OpExecError("Cannot shutdown instance disks, unable to"
+                                 " proceed with disk template conversion")
+      mode = (instance.disk_template, self.op.disk_template)
+      try:
+        self._DISK_CONVERSIONS[mode](self, feedback_fn)
+      except:
+        self.cfg.ReleaseDRBDMinors(instance.name)
+        raise
+      result.append(("disk_template", self.op.disk_template))
 
-    touched_nodes = frozenset(node_name for node_name in [self.new_node,
-                                                          self.other_node,
-                                                          self.target_node]
-                              if node_name is not None)
+      assert instance.disk_template == self.op.disk_template, \
+        ("Expected disk template '%s', found '%s'" %
+         (self.op.disk_template, instance.disk_template))
 
-    # Release unneeded node and node resource locks
-    _ReleaseLocks(self.lu, locking.LEVEL_NODE, keep=touched_nodes)
-    _ReleaseLocks(self.lu, locking.LEVEL_NODE_RES, keep=touched_nodes)
-    _ReleaseLocks(self.lu, locking.LEVEL_NODE_ALLOC)
+    # Release node and resource locks if there are any (they might already have
+    # been released during disk conversion)
+    ReleaseLocks(self, locking.LEVEL_NODE)
+    ReleaseLocks(self, locking.LEVEL_NODE_RES)
 
-    # Release any owned node group
-    _ReleaseLocks(self.lu, locking.LEVEL_NODEGROUP)
+    # Apply NIC changes
+    if self._new_nics is not None:
+      instance.nics = self._new_nics
+      result.extend(self._nic_chgdesc)
 
-    # Check whether disks are valid
-    for disk_idx in self.disks:
-      instance.FindDisk(disk_idx)
+    # hvparams changes
+    if self.op.hvparams:
+      instance.hvparams = self.hv_inst
+      for key, val in self.op.hvparams.iteritems():
+        result.append(("hv/%s" % key, val))
 
-    # Get secondary node IP addresses
-    self.node_secondary_ip = dict((name, node.secondary_ip) for (name, node)
-                                  in self.cfg.GetMultiNodeInfo(touched_nodes))
+    # beparams changes
+    if self.op.beparams:
+      instance.beparams = self.be_inst
+      for key, val in self.op.beparams.iteritems():
+        result.append(("be/%s" % key, val))
 
-  def Exec(self, feedback_fn):
-    """Execute disk replacement.
+    # OS change
+    if self.op.os_name:
+      instance.os = self.op.os_name
 
-    This dispatches the disk replacement to the appropriate handler.
+    # osparams changes
+    if self.op.osparams:
+      instance.osparams = self.os_inst
+      for key, val in self.op.osparams.iteritems():
+        result.append(("os/%s" % key, val))
 
-    """
-    if __debug__:
-      # Verify owned locks before starting operation
-      owned_nodes = self.lu.owned_locks(locking.LEVEL_NODE)
-      assert set(owned_nodes) == set(self.node_secondary_ip), \
-          ("Incorrect node locks, owning %s, expected %s" %
-           (owned_nodes, self.node_secondary_ip.keys()))
-      assert (self.lu.owned_locks(locking.LEVEL_NODE) ==
-              self.lu.owned_locks(locking.LEVEL_NODE_RES))
-      assert not self.lu.glm.is_owned(locking.LEVEL_NODE_ALLOC)
-
-      owned_instances = self.lu.owned_locks(locking.LEVEL_INSTANCE)
-      assert list(owned_instances) == [self.instance_name], \
-          "Instance '%s' not locked" % self.instance_name
-
-      assert not self.lu.glm.is_owned(locking.LEVEL_NODEGROUP), \
-          "Should not own any node group lock at this point"
-
-    if not self.disks:
-      feedback_fn("No disks need replacement for instance '%s'" %
-                  self.instance.name)
-      return
-
-    feedback_fn("Replacing disk(s) %s for instance '%s'" %
-                (utils.CommaJoin(self.disks), self.instance.name))
-    feedback_fn("Current primary node: %s" % self.instance.primary_node)
-    feedback_fn("Current seconary node: %s" %
-                utils.CommaJoin(self.instance.secondary_nodes))
-
-    activate_disks = (self.instance.admin_state != constants.ADMINST_UP)
-
-    # Activate the instance disks if we're replacing them on a down instance
-    if activate_disks:
-      _StartInstanceDisks(self.lu, self.instance, True)
+    if self.op.offline is None:
+      # Ignore
+      pass
+    elif self.op.offline:
+      # Mark instance as offline
+      self.cfg.MarkInstanceOffline(instance.name)
+      result.append(("admin_state", constants.ADMINST_OFFLINE))
+    else:
+      # Mark instance as online, but stopped
+      self.cfg.MarkInstanceDown(instance.name)
+      result.append(("admin_state", constants.ADMINST_DOWN))
 
-    try:
-      # Should we replace the secondary node?
-      if self.new_node is not None:
-        fn = self._ExecDrbd8Secondary
-      else:
-        fn = self._ExecDrbd8DiskOnly
+    self.cfg.Update(instance, feedback_fn, self.proc.GetECId())
 
-      result = fn(feedback_fn)
-    finally:
-      # Deactivate the instance disks if we're replacing them on a
-      # down instance
-      if activate_disks:
-        _SafeShutdownInstanceDisks(self.lu, self.instance)
-
-    assert not self.lu.owned_locks(locking.LEVEL_NODE)
-
-    if __debug__:
-      # Verify owned locks
-      owned_nodes = self.lu.owned_locks(locking.LEVEL_NODE_RES)
-      nodes = frozenset(self.node_secondary_ip)
-      assert ((self.early_release and not owned_nodes) or
-              (not self.early_release and not (set(owned_nodes) - nodes))), \
-        ("Not owning the correct locks, early_release=%s, owned=%r,"
-         " nodes=%r" % (self.early_release, owned_nodes, nodes))
+    assert not (self.owned_locks(locking.LEVEL_NODE_RES) or
+                self.owned_locks(locking.LEVEL_NODE)), \
+      "All node locks should have been released by now"
 
     return result
 
-  def _CheckVolumeGroup(self, nodes):
-    self.lu.LogInfo("Checking volume groups")
-
-    vgname = self.cfg.GetVGName()
-
-    # Make sure volume group exists on all involved nodes
-    results = self.rpc.call_vg_list(nodes)
-    if not results:
-      raise errors.OpExecError("Can't list volume groups on the nodes")
-
-    for node in nodes:
-      res = results[node]
-      res.Raise("Error checking node %s" % node)
-      if vgname not in res.payload:
-        raise errors.OpExecError("Volume group '%s' not found on node %s" %
-                                 (vgname, node))
-
-  def _CheckDisksExistence(self, nodes):
-    # Check disk existence
-    for idx, dev in enumerate(self.instance.disks):
-      if idx not in self.disks:
-        continue
-
-      for node in nodes:
-        self.lu.LogInfo("Checking disk/%d on %s", idx, node)
-        self.cfg.SetDiskID(dev, node)
+  _DISK_CONVERSIONS = {
+    (constants.DT_PLAIN, constants.DT_DRBD8): _ConvertPlainToDrbd,
+    (constants.DT_DRBD8, constants.DT_PLAIN): _ConvertDrbdToPlain,
+    }
 
-        result = _BlockdevFind(self, node, dev, self.instance)
 
-        msg = result.fail_msg
-        if msg or not result.payload:
-          if not msg:
-            msg = "disk not found"
-          raise errors.OpExecError("Can't find disk/%d on node %s: %s" %
-                                   (idx, node, msg))
+class LUInstanceChangeGroup(LogicalUnit):
+  HPATH = "instance-change-group"
+  HTYPE = constants.HTYPE_INSTANCE
+  REQ_BGL = False
 
-  def _CheckDisksConsistency(self, node_name, on_primary, ldisk):
-    for idx, dev in enumerate(self.instance.disks):
-      if idx not in self.disks:
-        continue
+  def ExpandNames(self):
+    self.share_locks = ShareAll()
 
-      self.lu.LogInfo("Checking disk/%d consistency on node %s" %
-                      (idx, node_name))
+    self.needed_locks = {
+      locking.LEVEL_NODEGROUP: [],
+      locking.LEVEL_NODE: [],
+      locking.LEVEL_NODE_ALLOC: locking.ALL_SET,
+      }
 
-      if not _CheckDiskConsistency(self.lu, self.instance, dev, node_name,
-                                   on_primary, ldisk=ldisk):
-        raise errors.OpExecError("Node %s has degraded storage, unsafe to"
-                                 " replace disks for instance %s" %
-                                 (node_name, self.instance.name))
+    self._ExpandAndLockInstance()
 
-  def _CreateNewStorage(self, node_name):
-    """Create new storage on the primary or secondary node.
+    if self.op.target_groups:
+      self.req_target_uuids = map(self.cfg.LookupNodeGroup,
+                                  self.op.target_groups)
+    else:
+      self.req_target_uuids = None
 
-    This is only used for same-node replaces, not for changing the
-    secondary node, hence we don't want to modify the existing disk.
+    self.op.iallocator = GetDefaultIAllocator(self.cfg, self.op.iallocator)
 
-    """
-    iv_names = {}
+  def DeclareLocks(self, level):
+    if level == locking.LEVEL_NODEGROUP:
+      assert not self.needed_locks[locking.LEVEL_NODEGROUP]
 
-    disks = _AnnotateDiskParams(self.instance, self.instance.disks, self.cfg)
-    for idx, dev in enumerate(disks):
-      if idx not in self.disks:
-        continue
+      if self.req_target_uuids:
+        lock_groups = set(self.req_target_uuids)
 
-      self.lu.LogInfo("Adding storage on %s for disk/%d", node_name, idx)
+        # Lock all groups used by instance optimistically; this requires going
+        # via the node before it's locked, requiring verification later on
+        instance_groups = self.cfg.GetInstanceNodeGroups(self.op.instance_name)
+        lock_groups.update(instance_groups)
+      else:
+        # No target groups, need to lock all of them
+        lock_groups = locking.ALL_SET
 
-      self.cfg.SetDiskID(dev, node_name)
+      self.needed_locks[locking.LEVEL_NODEGROUP] = lock_groups
 
-      lv_names = [".disk%d_%s" % (idx, suffix) for suffix in ["data", "meta"]]
-      names = _GenerateUniqueNames(self.lu, lv_names)
+    elif level == locking.LEVEL_NODE:
+      if self.req_target_uuids:
+        # Lock all nodes used by instances
+        self.recalculate_locks[locking.LEVEL_NODE] = constants.LOCKS_APPEND
+        self._LockInstancesNodes()
 
-      (data_disk, meta_disk) = dev.children
-      vg_data = data_disk.logical_id[0]
-      lv_data = objects.Disk(dev_type=constants.LD_LV, size=dev.size,
-                             logical_id=(vg_data, names[0]),
-                             params=data_disk.params)
-      vg_meta = meta_disk.logical_id[0]
-      lv_meta = objects.Disk(dev_type=constants.LD_LV,
-                             size=constants.DRBD_META_SIZE,
-                             logical_id=(vg_meta, names[1]),
-                             params=meta_disk.params)
+        # Lock all nodes in all potential target groups
+        lock_groups = (frozenset(self.owned_locks(locking.LEVEL_NODEGROUP)) -
+                       self.cfg.GetInstanceNodeGroups(self.op.instance_name))
+        member_nodes = [node_name
+                        for group in lock_groups
+                        for node_name in self.cfg.GetNodeGroup(group).members]
+        self.needed_locks[locking.LEVEL_NODE].extend(member_nodes)
+      else:
+        # Lock all nodes as all groups are potential targets
+        self.needed_locks[locking.LEVEL_NODE] = locking.ALL_SET
 
-      new_lvs = [lv_data, lv_meta]
-      old_lvs = [child.Copy() for child in dev.children]
-      iv_names[dev.iv_name] = (dev, old_lvs, new_lvs)
-      excl_stor = _IsExclusiveStorageEnabledNodeName(self.lu.cfg, node_name)
+  def CheckPrereq(self):
+    owned_instances = frozenset(self.owned_locks(locking.LEVEL_INSTANCE))
+    owned_groups = frozenset(self.owned_locks(locking.LEVEL_NODEGROUP))
+    owned_nodes = frozenset(self.owned_locks(locking.LEVEL_NODE))
 
-      # we pass force_create=True to force the LVM creation
-      for new_lv in new_lvs:
-        _CreateBlockDevInner(self.lu, node_name, self.instance, new_lv, True,
-                             _GetInstanceInfoText(self.instance), False,
-                             excl_stor)
+    assert (self.req_target_uuids is None or
+            owned_groups.issuperset(self.req_target_uuids))
+    assert owned_instances == set([self.op.instance_name])
 
-    return iv_names
+    # Get instance information
+    self.instance = self.cfg.GetInstanceInfo(self.op.instance_name)
 
-  def _CheckDevices(self, node_name, iv_names):
-    for name, (dev, _, _) in iv_names.iteritems():
-      self.cfg.SetDiskID(dev, node_name)
+    # Check if node groups for locked instance are still correct
+    assert owned_nodes.issuperset(self.instance.all_nodes), \
+      ("Instance %s's nodes changed while we kept the lock" %
+       self.op.instance_name)
 
-      result = _BlockdevFind(self, node_name, dev, self.instance)
+    inst_groups = CheckInstanceNodeGroups(self.cfg, self.op.instance_name,
+                                          owned_groups)
 
-      msg = result.fail_msg
-      if msg or not result.payload:
-        if not msg:
-          msg = "disk not found"
-        raise errors.OpExecError("Can't find DRBD device %s: %s" %
-                                 (name, msg))
+    if self.req_target_uuids:
+      # User requested specific target groups
+      self.target_uuids = frozenset(self.req_target_uuids)
+    else:
+      # All groups except those used by the instance are potential targets
+      self.target_uuids = owned_groups - inst_groups
 
-      if result.payload.is_degraded:
-        raise errors.OpExecError("DRBD device %s is degraded!" % name)
+    conflicting_groups = self.target_uuids & inst_groups
+    if conflicting_groups:
+      raise errors.OpPrereqError("Can't use group(s) '%s' as targets, they are"
+                                 " used by the instance '%s'" %
+                                 (utils.CommaJoin(conflicting_groups),
+                                  self.op.instance_name),
+                                 errors.ECODE_INVAL)
 
-  def _RemoveOldStorage(self, node_name, iv_names):
-    for name, (_, old_lvs, _) in iv_names.iteritems():
-      self.lu.LogInfo("Remove logical volumes for %s", name)
+    if not self.target_uuids:
+      raise errors.OpPrereqError("There are no possible target groups",
+                                 errors.ECODE_INVAL)
 
-      for lv in old_lvs:
-        self.cfg.SetDiskID(lv, node_name)
+  def BuildHooksEnv(self):
+    """Build hooks env.
 
-        msg = self.rpc.call_blockdev_remove(node_name, lv).fail_msg
-        if msg:
-          self.lu.LogWarning("Can't remove old LV: %s", msg,
-                             hint="remove unused LVs manually")
+    """
+    assert self.target_uuids
 
-  def _ExecDrbd8DiskOnly(self, feedback_fn): # pylint: disable=W0613
-    """Replace a disk on the primary or secondary for DRBD 8.
+    env = {
+      "TARGET_GROUPS": " ".join(self.target_uuids),
+      }
 
-    The algorithm for replace is quite complicated:
+    env.update(BuildInstanceHookEnvByObject(self, self.instance))
 
-      1. for each disk to be replaced:
+    return env
 
-        1. create new LVs on the target node with unique names
-        1. detach old LVs from the drbd device
-        1. rename old LVs to name_replaced.<time_t>
-        1. rename new LVs to old LVs
-        1. attach the new LVs (with the old names now) to the drbd device
+  def BuildHooksNodes(self):
+    """Build hooks nodes.
 
-      1. wait for sync across all devices
+    """
+    mn = self.cfg.GetMasterNode()
+    return ([mn], [mn])
 
-      1. for each modified disk:
+  def Exec(self, feedback_fn):
+    instances = list(self.owned_locks(locking.LEVEL_INSTANCE))
 
-        1. remove old LVs (which have the name name_replaces.<time_t>)
+    assert instances == [self.op.instance_name], "Instance not locked"
 
-    Failures are not very well handled.
+    req = iallocator.IAReqGroupChange(instances=instances,
+                                      target_groups=list(self.target_uuids))
+    ial = iallocator.IAllocator(self.cfg, self.rpc, req)
 
-    """
-    steps_total = 6
-
-    # Step: check device activation
-    self.lu.LogStep(1, steps_total, "Check device existence")
-    self._CheckDisksExistence([self.other_node, self.target_node])
-    self._CheckVolumeGroup([self.target_node, self.other_node])
-
-    # Step: check other node consistency
-    self.lu.LogStep(2, steps_total, "Check peer consistency")
-    self._CheckDisksConsistency(self.other_node,
-                                self.other_node == self.instance.primary_node,
-                                False)
-
-    # Step: create new storage
-    self.lu.LogStep(3, steps_total, "Allocate new storage")
-    iv_names = self._CreateNewStorage(self.target_node)
-
-    # Step: for each lv, detach+rename*2+attach
-    self.lu.LogStep(4, steps_total, "Changing drbd configuration")
-    for dev, old_lvs, new_lvs in iv_names.itervalues():
-      self.lu.LogInfo("Detaching %s drbd from local storage", dev.iv_name)
-
-      result = self.rpc.call_blockdev_removechildren(self.target_node, dev,
-                                                     old_lvs)
-      result.Raise("Can't detach drbd from local storage on node"
-                   " %s for device %s" % (self.target_node, dev.iv_name))
-      #dev.children = []
-      #cfg.Update(instance)
-
-      # ok, we created the new LVs, so now we know we have the needed
-      # storage; as such, we proceed on the target node to rename
-      # old_lv to _old, and new_lv to old_lv; note that we rename LVs
-      # using the assumption that logical_id == physical_id (which in
-      # turn is the unique_id on that node)
-
-      # FIXME(iustin): use a better name for the replaced LVs
-      temp_suffix = int(time.time())
-      ren_fn = lambda d, suff: (d.physical_id[0],
-                                d.physical_id[1] + "_replaced-%s" % suff)
-
-      # Build the rename list based on what LVs exist on the node
-      rename_old_to_new = []
-      for to_ren in old_lvs:
-        result = self.rpc.call_blockdev_find(self.target_node, to_ren)
-        if not result.fail_msg and result.payload:
-          # device exists
-          rename_old_to_new.append((to_ren, ren_fn(to_ren, temp_suffix)))
-
-      self.lu.LogInfo("Renaming the old LVs on the target node")
-      result = self.rpc.call_blockdev_rename(self.target_node,
-                                             rename_old_to_new)
-      result.Raise("Can't rename old LVs on node %s" % self.target_node)
-
-      # Now we rename the new LVs to the old LVs
-      self.lu.LogInfo("Renaming the new LVs on the target node")
-      rename_new_to_old = [(new, old.physical_id)
-                           for old, new in zip(old_lvs, new_lvs)]
-      result = self.rpc.call_blockdev_rename(self.target_node,
-                                             rename_new_to_old)
-      result.Raise("Can't rename new LVs on node %s" % self.target_node)
-
-      # Intermediate steps of in memory modifications
-      for old, new in zip(old_lvs, new_lvs):
-        new.logical_id = old.logical_id
-        self.cfg.SetDiskID(new, self.target_node)
-
-      # We need to modify old_lvs so that removal later removes the
-      # right LVs, not the newly added ones; note that old_lvs is a
-      # copy here
-      for disk in old_lvs:
-        disk.logical_id = ren_fn(disk, temp_suffix)
-        self.cfg.SetDiskID(disk, self.target_node)
-
-      # Now that the new lvs have the old name, we can add them to the device
-      self.lu.LogInfo("Adding new mirror component on %s", self.target_node)
-      result = self.rpc.call_blockdev_addchildren(self.target_node,
-                                                  (dev, self.instance), new_lvs)
-      msg = result.fail_msg
-      if msg:
-        for new_lv in new_lvs:
-          msg2 = self.rpc.call_blockdev_remove(self.target_node,
-                                               new_lv).fail_msg
-          if msg2:
-            self.lu.LogWarning("Can't rollback device %s: %s", dev, msg2,
-                               hint=("cleanup manually the unused logical"
-                                     "volumes"))
-        raise errors.OpExecError("Can't add local storage to drbd: %s" % msg)
-
-    cstep = itertools.count(5)
-
-    if self.early_release:
-      self.lu.LogStep(cstep.next(), steps_total, "Removing old storage")
-      self._RemoveOldStorage(self.target_node, iv_names)
-      # TODO: Check if releasing locks early still makes sense
-      _ReleaseLocks(self.lu, locking.LEVEL_NODE_RES)
-    else:
-      # Release all resource locks except those used by the instance
-      _ReleaseLocks(self.lu, locking.LEVEL_NODE_RES,
-                    keep=self.node_secondary_ip.keys())
-
-    # Release all node locks while waiting for sync
-    _ReleaseLocks(self.lu, locking.LEVEL_NODE)
-
-    # TODO: Can the instance lock be downgraded here? Take the optional disk
-    # shutdown in the caller into consideration.
-
-    # Wait for sync
-    # This can fail as the old devices are degraded and _WaitForSync
-    # does a combined result over all disks, so we don't check its return value
-    self.lu.LogStep(cstep.next(), steps_total, "Sync devices")
-    _WaitForSync(self.lu, self.instance)
-
-    # Check all devices manually
-    self._CheckDevices(self.instance.primary_node, iv_names)
-
-    # Step: remove old storage
-    if not self.early_release:
-      self.lu.LogStep(cstep.next(), steps_total, "Removing old storage")
-      self._RemoveOldStorage(self.target_node, iv_names)
-
-  def _ExecDrbd8Secondary(self, feedback_fn):
-    """Replace the secondary node for DRBD 8.
-
-    The algorithm for replace is quite complicated:
-      - for all disks of the instance:
-        - create new LVs on the new node with same names
-        - shutdown the drbd device on the old secondary
-        - disconnect the drbd network on the primary
-        - create the drbd device on the new secondary
-        - network attach the drbd on the primary, using an artifice:
-          the drbd code for Attach() will connect to the network if it
-          finds a device which is connected to the good local disks but
-          not network enabled
-      - wait for sync across all devices
-      - remove all disks from the old secondary
-
-    Failures are not very well handled.
+    ial.Run(self.op.iallocator)
 
-    """
-    steps_total = 6
-
-    pnode = self.instance.primary_node
-
-    # Step: check device activation
-    self.lu.LogStep(1, steps_total, "Check device existence")
-    self._CheckDisksExistence([self.instance.primary_node])
-    self._CheckVolumeGroup([self.instance.primary_node])
-
-    # Step: check other node consistency
-    self.lu.LogStep(2, steps_total, "Check peer consistency")
-    self._CheckDisksConsistency(self.instance.primary_node, True, True)
-
-    # Step: create new storage
-    self.lu.LogStep(3, steps_total, "Allocate new storage")
-    disks = _AnnotateDiskParams(self.instance, self.instance.disks, self.cfg)
-    excl_stor = _IsExclusiveStorageEnabledNodeName(self.lu.cfg, self.new_node)
-    for idx, dev in enumerate(disks):
-      self.lu.LogInfo("Adding new local storage on %s for disk/%d" %
-                      (self.new_node, idx))
-      # we pass force_create=True to force LVM creation
-      for new_lv in dev.children:
-        _CreateBlockDevInner(self.lu, self.new_node, self.instance, new_lv,
-                             True, _GetInstanceInfoText(self.instance), False,
-                             excl_stor)
-
-    # Step 4: dbrd minors and drbd setups changes
-    # after this, we must manually remove the drbd minors on both the
-    # error and the success paths
-    self.lu.LogStep(4, steps_total, "Changing drbd configuration")
-    minors = self.cfg.AllocateDRBDMinor([self.new_node
-                                         for dev in self.instance.disks],
-                                        self.instance.name)
-    logging.debug("Allocated minors %r", minors)
-
-    iv_names = {}
-    for idx, (dev, new_minor) in enumerate(zip(self.instance.disks, minors)):
-      self.lu.LogInfo("activating a new drbd on %s for disk/%d" %
-                      (self.new_node, idx))
-      # create new devices on new_node; note that we create two IDs:
-      # one without port, so the drbd will be activated without
-      # networking information on the new node at this stage, and one
-      # with network, for the latter activation in step 4
-      (o_node1, o_node2, o_port, o_minor1, o_minor2, o_secret) = dev.logical_id
-      if self.instance.primary_node == o_node1:
-        p_minor = o_minor1
-      else:
-        assert self.instance.primary_node == o_node2, "Three-node instance?"
-        p_minor = o_minor2
-
-      new_alone_id = (self.instance.primary_node, self.new_node, None,
-                      p_minor, new_minor, o_secret)
-      new_net_id = (self.instance.primary_node, self.new_node, o_port,
-                    p_minor, new_minor, o_secret)
-
-      iv_names[idx] = (dev, dev.children, new_net_id)
-      logging.debug("Allocated new_minor: %s, new_logical_id: %s", new_minor,
-                    new_net_id)
-      new_drbd = objects.Disk(dev_type=constants.LD_DRBD8,
-                              logical_id=new_alone_id,
-                              children=dev.children,
-                              size=dev.size,
-                              params={})
-      (anno_new_drbd,) = _AnnotateDiskParams(self.instance, [new_drbd],
-                                             self.cfg)
-      try:
-        _CreateSingleBlockDev(self.lu, self.new_node, self.instance,
-                              anno_new_drbd,
-                              _GetInstanceInfoText(self.instance), False,
-                              excl_stor)
-      except errors.GenericError:
-        self.cfg.ReleaseDRBDMinors(self.instance.name)
-        raise
+    if not ial.success:
+      raise errors.OpPrereqError("Can't compute solution for changing group of"
+                                 " instance '%s' using iallocator '%s': %s" %
+                                 (self.op.instance_name, self.op.iallocator,
+                                  ial.info), errors.ECODE_NORES)
 
-    # We have new devices, shutdown the drbd on the old secondary
-    for idx, dev in enumerate(self.instance.disks):
-      self.lu.LogInfo("Shutting down drbd for disk/%d on old node", idx)
-      self.cfg.SetDiskID(dev, self.target_node)
-      msg = self.rpc.call_blockdev_shutdown(self.target_node,
-                                            (dev, self.instance)).fail_msg
-      if msg:
-        self.lu.LogWarning("Failed to shutdown drbd for disk/%d on old"
-                           "node: %s" % (idx, msg),
-                           hint=("Please cleanup this device manually as"
-                                 " soon as possible"))
+    jobs = LoadNodeEvacResult(self, ial.result, self.op.early_release, False)
 
-    self.lu.LogInfo("Detaching primary drbds from the network (=> standalone)")
-    result = self.rpc.call_drbd_disconnect_net([pnode], self.node_secondary_ip,
-                                               self.instance.disks)[pnode]
+    self.LogInfo("Iallocator returned %s job(s) for changing group of"
+                 " instance '%s'", len(jobs), self.op.instance_name)
 
-    msg = result.fail_msg
-    if msg:
-      # detaches didn't succeed (unlikely)
-      self.cfg.ReleaseDRBDMinors(self.instance.name)
-      raise errors.OpExecError("Can't detach the disks from the network on"
-                               " old node: %s" % (msg,))
-
-    # if we managed to detach at least one, we update all the disks of
-    # the instance to point to the new secondary
-    self.lu.LogInfo("Updating instance configuration")
-    for dev, _, new_logical_id in iv_names.itervalues():
-      dev.logical_id = new_logical_id
-      self.cfg.SetDiskID(dev, self.instance.primary_node)
-
-    self.cfg.Update(self.instance, feedback_fn)
-
-    # Release all node locks (the configuration has been updated)
-    _ReleaseLocks(self.lu, locking.LEVEL_NODE)
-
-    # and now perform the drbd attach
-    self.lu.LogInfo("Attaching primary drbds to new secondary"
-                    " (standalone => connected)")
-    result = self.rpc.call_drbd_attach_net([self.instance.primary_node,
-                                            self.new_node],
-                                           self.node_secondary_ip,
-                                           (self.instance.disks, self.instance),
-                                           self.instance.name,
-                                           False)
-    for to_node, to_result in result.items():
-      msg = to_result.fail_msg
-      if msg:
-        self.lu.LogWarning("Can't attach drbd disks on node %s: %s",
-                           to_node, msg,
-                           hint=("please do a gnt-instance info to see the"
-                                 " status of disks"))
-
-    cstep = itertools.count(5)
-
-    if self.early_release:
-      self.lu.LogStep(cstep.next(), steps_total, "Removing old storage")
-      self._RemoveOldStorage(self.target_node, iv_names)
-      # TODO: Check if releasing locks early still makes sense
-      _ReleaseLocks(self.lu, locking.LEVEL_NODE_RES)
-    else:
-      # Release all resource locks except those used by the instance
-      _ReleaseLocks(self.lu, locking.LEVEL_NODE_RES,
-                    keep=self.node_secondary_ip.keys())
-
-    # TODO: Can the instance lock be downgraded here? Take the optional disk
-    # shutdown in the caller into consideration.
-
-    # Wait for sync
-    # This can fail as the old devices are degraded and _WaitForSync
-    # does a combined result over all disks, so we don't check its return value
-    self.lu.LogStep(cstep.next(), steps_total, "Sync devices")
-    _WaitForSync(self.lu, self.instance)
-
-    # Check all devices manually
-    self._CheckDevices(self.instance.primary_node, iv_names)
-
-    # Step: remove old storage
-    if not self.early_release:
-      self.lu.LogStep(cstep.next(), steps_total, "Removing old storage")
-      self._RemoveOldStorage(self.target_node, iv_names)
+    return ResultWithJobs(jobs)