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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

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# 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

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# 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

The syntax for the _CHECK variables and the contents of the PARAMETERS

dict is the same, see the docstring for L{BaseHypervisor.PARAMETERS}.

@var _FILE_CHECK: stub for file checks, without the required flag

@var _DIR_CHECK: stub for directory checks, without the required flag

@var REQ_FILE_CHECK: mandatory file parameter

@var OPT_FILE_CHECK: optional file parameter

@var REQ_DIR_CHECK: mandatory directory parametr

@var OPT_DIR_CHECK: optional directory parameter

@var NO_CHECK: parameter without any checks at all

@var REQUIRED_CHECK: parameter required to exist (and non-false), but

    without other checks; beware that this can't be used for boolean

    parameters, where you should use NO_CHECK or a custom checker

"""

import os

import re

import logging

from ganeti import errors

from ganeti import utils

# Read the BaseHypervisor.PARAMETERS docstring for the syntax of the

# _CHECK values

# must be afile

_FILE_CHECK = (utils.IsNormAbsPath, "must be an absolute normalized path",

              os.path.isfile, "not found or not a file")

# must be a directory

_DIR_CHECK = (utils.IsNormAbsPath, "must be an absolute normalized path",

             os.path.isdir, "not found or not a directory")

# nice wrappers for users

REQ_FILE_CHECK = (True, ) + _FILE_CHECK

OPT_FILE_CHECK = (False, ) + _FILE_CHECK

REQ_DIR_CHECK = (True, ) + _DIR_CHECK

OPT_DIR_CHECK = (False, ) + _DIR_CHECK

# no checks at all

NO_CHECK = (False, None, None, None, None)

# required, but no other checks

REQUIRED_CHECK = (True, None, None, None, None)

def ParamInSet(required, my_set):

  """Builds parameter checker for set membership.

  @type required: boolean

  @param required: whether this is a required parameter

  @type my_set: tuple, list or set

  @param my_set: allowed values set

  """

  fn = lambda x: x in my_set

  err = ("The value must be one of: %s" % utils.CommaJoin(my_set))

  return (required, fn, err, None, None)

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.

  @cvar PARAMETERS: a dict of parameter name: check type; the check type is

      a five-tuple containing:

          - the required flag (boolean)

          - a function to check for syntax, that will be used in

            L{CheckParameterSyntax}, in the master daemon process

          - an error message for the above function

          - a function to check for parameter validity on the remote node,

            in the L{ValidateParameters} function

          - an error message for the above function

  """

  PARAMETERS = {}

  ANCILLARY_FILES = []

  def __init__(self):

    pass

  def StartInstance(self, instance, block_devices):

    """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

  @classmethod

  def GetShellCommandForConsole(cls, instance, hvparams, beparams):

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

    """

    raise NotImplementedError

  @classmethod

  def GetAncillaryFiles(cls):

    """Return a list of ancillary files to be copied to all nodes as ancillary

    configuration files.

    @rtype: list of strings

    @return: list of absolute paths of files to ship cluster-wide

    """

    # By default we return a member variable, so that if an hypervisor has just

    # a static list of files it doesn't have to override this function.

    return cls.ANCILLARY_FILES

  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("Parameter '%s' is not supported" % key)

    # cheap tests that run on the master, should not access the world

    for name, (required, check_fn, errstr, _, _) in cls.PARAMETERS.items():

      if name not in hvparams:

        raise errors.HypervisorError("Parameter '%s' is missing" % name)

      value = hvparams[name]

      if not required and not value:

        continue

      if not value:

        raise errors.HypervisorError("Parameter '%s' is required but"

                                     " is currently not defined" % (name, ))

      if check_fn is not None and not check_fn(value):

        raise errors.HypervisorError("Parameter '%s' fails syntax"

                                     " check: %s (current value: '%s')" %

                                     (name, errstr, value))

  @classmethod

  def ValidateParameters(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 name, (required, _, _, check_fn, errstr) in cls.PARAMETERS.items():

      value = hvparams[name]

      if not required and not value:

        continue

      if check_fn is not None and not check_fn(value):

        raise errors.HypervisorError("Parameter '%s' fails"

                                     " validation: %s (current value: '%s')" %

                                     (name, errstr, value))

  @classmethod

  def PowercycleNode(cls):

    """Hard powercycle a node using hypervisor specific methods.

    This method should hard powercycle the node, using whatever

    methods the hypervisor provides. Note that this means that all

    instances running on the node must be stopped too.

    """

    raise NotImplementedError

  def GetLinuxNodeInfo(self):

    """For linux systems, return actual OS information.

    This is an abstraction for all non-hypervisor-based classes, where

    the node actually sees all the memory and CPUs via the /proc

    interface and standard commands. The other case if for example

    xen, where you only see the hardware resources via xen-specific

    tools.

    @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

    """

    try:

      data = utils.ReadFile("/proc/meminfo").splitlines()

    except EnvironmentError, err:

      raise errors.HypervisorError("Failed to list node info: %s" % (err,))

    result = {}

    sum_free = 0

    try:

      for line in data:

        splitfields = line.split(":", 1)

        if len(splitfields) > 1:

          key = splitfields[0].strip()

          val = splitfields[1].strip()

          if key == 'MemTotal':

            result['memory_total'] = int(val.split()[0])/1024

          elif key in ('MemFree', 'Buffers', 'Cached'):

            sum_free += int(val.split()[0])/1024

          elif key == 'Active':

            result['memory_dom0'] = int(val.split()[0])/1024

    except (ValueError, TypeError), err:

      raise errors.HypervisorError("Failed to compute memory usage: %s" %

                                   (err,))

    result['memory_free'] = sum_free

    cpu_total = 0

    try:

      fh = open("/proc/cpuinfo")

      try:

        cpu_total = len(re.findall("(?m)^processor\s*:\s*[0-9]+\s*$",

                                   fh.read()))

      finally:

        fh.close()

    except EnvironmentError, err:

      raise errors.HypervisorError("Failed to list node info: %s" % (err,))

    result['cpu_total'] = cpu_total

    # FIXME: export correct data here

    result['cpu_nodes'] = 1

    result['cpu_sockets'] = 1

    return result

  @classmethod

  def LinuxPowercycle(cls):

    """Linux-specific powercycle method.

    """

    try:

      fd = os.open("/proc/sysrq-trigger", os.O_WRONLY)

      try:

        os.write(fd, "b")

      finally:

        fd.close()

    except OSError:

      logging.exception("Can't open the sysrq-trigger file")

      result = utils.RunCmd(["reboot", "-n", "-f"])

      if not result:

        logging.error("Can't run shutdown: %s", result.output)