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#

# Copyright (C) 2006, 2007, 2008 Google Inc.

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# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

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# This program is distributed in the hope that it will be useful, but

# WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

# General Public License for more details.

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# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.

"""Base class for all hypervisors

"""

from ganeti import errors

class BaseHypervisor(object):

  """Abstract virtualisation technology interface

  The goal is that all aspects of the virtualisation technology are

  abstracted away from the rest of code.

  """

  PARAMETERS = []

  def __init__(self):

    pass

  def StartInstance(self, instance, block_devices, extra_args):

    """Start an instance."""

    raise NotImplementedError

  def StopInstance(self, instance, force=False):

    """Stop an instance."""

    raise NotImplementedError

  def RebootInstance(self, instance):

    """Reboot an instance."""

    raise NotImplementedError

  def ListInstances(self):

    """Get the list of running instances."""

    raise NotImplementedError

  def GetInstanceInfo(self, instance_name):

    """Get instance properties.

    @type instance_name: string

    @param instance_name: the instance name

    @return: tuple (name, id, memory, vcpus, state, times)

    """

    raise NotImplementedError

  def GetAllInstancesInfo(self):

    """Get properties of all instances.

    @return: list of tuples (name, id, memory, vcpus, stat, times)

    """

    raise NotImplementedError

  def GetNodeInfo(self):

    """Return information about the node.

    @return: a dict with the following keys (values in MiB):

          - memory_total: the total memory size on the node

          - memory_free: the available memory on the node for instances

          - memory_dom0: the memory used by the node itself, if available

    """

    raise NotImplementedError

  @staticmethod

  def GetShellCommandForConsole(instance):

    """Return a command for connecting to the console of an instance.

    """

    raise NotImplementedError

  def Verify(self):

    """Verify the hypervisor.

    """

    raise NotImplementedError

  def MigrationInfo(self, instance):

    """Get instance information to perform a migration.

    By default assume no information is needed.

    @type instance: L{objects.Instance}

    @param instance: instance to be migrated

    @rtype: string/data (opaque)

    @return: instance migration information - serialized form

    """

    return ''

  def AcceptInstance(self, instance, info, target):

    """Prepare to accept an instance.

    By default assume no preparation is needed.

    @type instance: L{objects.Instance}

    @param instance: instance to be accepted

    @type info: string/data (opaque)

    @param info: migration information, from the source node

    @type target: string

    @param target: target host (usually ip), on this node

    """

    pass

  def FinalizeMigration(self, instance, info, success):

    """Finalized an instance migration.

    Should finalize or revert any preparation done to accept the instance.

    Since by default we do no preparation, we also don't have anything to do

    @type instance: L{objects.Instance}

    @param instance: instance whose migration is being aborted

    @type info: string/data (opaque)

    @param info: migration information, from the source node

    @type success: boolean

    @param success: whether the migration was a success or a failure

    """

    pass

  def MigrateInstance(self, name, target, live):

    """Migrate an instance.

    @type name: string

    @param name: name of the instance to be migrated

    @type target: string

    @param target: hostname (usually ip) of the target node

    @type live: boolean

    @param live: whether to do a live or non-live migration

    """

    raise NotImplementedError

  @classmethod

  def CheckParameterSyntax(cls, hvparams):

    """Check the given parameters for validity.

    This should check the passed set of parameters for

    validity. Classes should extend, not replace, this function.

    @type hvparams:  dict

    @param hvparams: dictionary with parameter names/value

    @raise errors.HypervisorError: when a parameter is not valid

    """

    for key in hvparams:

      if key not in cls.PARAMETERS:

        raise errors.HypervisorError("Hypervisor parameter '%s'"

                                     " not supported" % key)

    for key in cls.PARAMETERS:

      if key not in hvparams:

        raise errors.HypervisorError("Hypervisor parameter '%s'"

                                     " missing" % key)

  def ValidateParameters(self, hvparams):

    """Check the given parameters for validity.

    This should check the passed set of parameters for

    validity. Classes should extend, not replace, this function.

    @type hvparams:  dict

    @param hvparams: dictionary with parameter names/value

    @raise errors.HypervisorError: when a parameter is not valid

    """

    pass