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#

#

# Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Google Inc.

#

# 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

# (at your option) any later version.

#

# 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.

"""Xen hypervisors

"""

import logging

import errno

import string # pylint: disable=W0402

import shutil

from cStringIO import StringIO

from ganeti import constants

from ganeti import errors

from ganeti import utils

from ganeti.hypervisor import hv_base

from ganeti import netutils

from ganeti import objects

from ganeti import pathutils

XEND_CONFIG_FILE = utils.PathJoin(pathutils.XEN_CONFIG_DIR, "xend-config.sxp")

XL_CONFIG_FILE = utils.PathJoin(pathutils.XEN_CONFIG_DIR, "xen/xl.conf")

VIF_BRIDGE_SCRIPT = utils.PathJoin(pathutils.XEN_CONFIG_DIR,

                                   "scripts/vif-bridge")

_DOM0_NAME = "Domain-0"

_DISK_LETTERS = string.ascii_lowercase

_FILE_DRIVER_MAP = {

  constants.FD_LOOP: "file",

  constants.FD_BLKTAP: "tap:aio",

  constants.FD_BLKTAP2: "tap2:tapdisk:aio",

  }

def _CreateConfigCpus(cpu_mask):

  """Create a CPU config string for Xen's config file.

  """

  # Convert the string CPU mask to a list of list of int's

  cpu_list = utils.ParseMultiCpuMask(cpu_mask)

  if len(cpu_list) == 1:

    all_cpu_mapping = cpu_list[0]

    if all_cpu_mapping == constants.CPU_PINNING_OFF:

      # If CPU pinning has 1 entry that's "all", then remove the

      # parameter from the config file

      return None

    else:

      # If CPU pinning has one non-all entry, mapping all vCPUS (the entire

      # VM) to one physical CPU, using format 'cpu = "C"'

      return "cpu = \"%s\"" % ",".join(map(str, all_cpu_mapping))

  else:

    def _GetCPUMap(vcpu):

      if vcpu[0] == constants.CPU_PINNING_ALL_VAL:

        cpu_map = constants.CPU_PINNING_ALL_XEN

      else:

        cpu_map = ",".join(map(str, vcpu))

      return "\"%s\"" % cpu_map

    # build the result string in format 'cpus = [ "c", "c", "c" ]',

    # where each c is a physical CPU number, a range, a list, or any

    # combination

    return "cpus = [ %s ]" % ", ".join(map(_GetCPUMap, cpu_list))

def _RunInstanceList(fn, instance_list_errors):

  """Helper function for L{_GetAllInstanceList} to retrieve the list

  of instances from xen.

  @type fn: callable

  @param fn: Function to query xen for the list of instances

  @type instance_list_errors: list

  @param instance_list_errors: Error list

  @rtype: list

  """

  result = fn()

  if result.failed:

    logging.error("Retrieving the instance list from xen failed (%s): %s",

                  result.fail_reason, result.output)

    instance_list_errors.append(result)

    raise utils.RetryAgain()

  # skip over the heading

  return result.stdout.splitlines()

def _ParseInstanceList(lines, include_node):

  """Parses the output of listing instances by xen.

  @type lines: list

  @param lines: Result of retrieving the instance list from xen

  @type include_node: boolean

  @param include_node: If True, return information for Dom0

  @return: list of tuple containing (name, id, memory, vcpus, state, time

    spent)

  """

  result = []

  # Iterate through all lines while ignoring header

  for line in lines[1:]:

    # The format of lines is:

    # Name      ID Mem(MiB) VCPUs State  Time(s)

    # Domain-0   0  3418     4 r-----    266.2

    data = line.split()

    if len(data) != 6:

      raise errors.HypervisorError("Can't parse instance list,"

                                   " line: %s" % line)

    try:

      data[1] = int(data[1])

      data[2] = int(data[2])

      data[3] = int(data[3])

      data[4] = _XenToHypervisorInstanceState(data[4])

      data[5] = float(data[5])

    except (TypeError, ValueError), err:

      raise errors.HypervisorError("Can't parse instance list,"

                                   " line: %s, error: %s" % (line, err))

    # skip the Domain-0 (optional)

    if include_node or data[0] != _DOM0_NAME:

      result.append(data)

  return result

def _GetAllInstanceList(fn, include_node, _timeout=5):

  """Return the list of instances including running and shutdown.

  See L{_RunInstanceList} and L{_ParseInstanceList} for parameter details.

  """

  instance_list_errors = []

  try:

    lines = utils.Retry(_RunInstanceList, (0.3, 1.5, 1.0), _timeout,

                        args=(fn, instance_list_errors))

  except utils.RetryTimeout:

    if instance_list_errors:

      instance_list_result = instance_list_errors.pop()

      errmsg = ("listing instances failed, timeout exceeded (%s): %s" %

                (instance_list_result.fail_reason, instance_list_result.output))

    else:

      errmsg = "listing instances failed"

    raise errors.HypervisorError(errmsg)

  return _ParseInstanceList(lines, include_node)

# Determine whether an instance is running

#

# An instance is running if it is in the following Xen states:

# running, blocked, or paused.

def _IsInstanceRunning(instance_info):

  return instance_info == "r-----" \

      or instance_info == "-b----" \

      or instance_info == "--p---"

def _IsInstanceShutdown(instance_info):

  return instance_info == "---s--"

def _XenToHypervisorInstanceState(instance_info):

  if _IsInstanceRunning(instance_info):

    return hv_base.HvInstanceState.RUNNING

  elif _IsInstanceShutdown(instance_info):

    return hv_base.HvInstanceState.SHUTDOWN

  else:

    raise errors.HypervisorError("hv_xen._XenToHypervisorInstanceState:"

                                 " unhandled Xen instance state '%s'" %

                                   instance_info)

def _GetRunningInstanceList(fn, include_node, _timeout=5):

  """Return the list of running instances.

  See L{_GetAllInstanceList} for parameter details.

  """

  instances = _GetAllInstanceList(fn, include_node, _timeout)

  return [i for i in instances if hv_base.HvInstanceState.IsRunning(i[4])]

def _GetShutdownInstanceList(fn, include_node, _timeout=5):

  """Return the list of shutdown instances.

  See L{_GetAllInstanceList} for parameter details.

  """

  instances = _GetAllInstanceList(fn, include_node, _timeout)

  return [i for i in instances if hv_base.HvInstanceState.IsShutdown(i[4])]

def _ParseNodeInfo(info):

  """Return information about the node.

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

        - memory_total: the total memory size on the node

        - memory_free: the available memory on the node for instances

        - nr_cpus: total number of CPUs

        - nr_nodes: in a NUMA system, the number of domains

        - nr_sockets: the number of physical CPU sockets in the node

        - hv_version: the hypervisor version in the form (major, minor)

  """

  result = {}

  cores_per_socket = threads_per_core = nr_cpus = None

  xen_major, xen_minor = None, None

  memory_total = None

  memory_free = None

  for line in info.splitlines():

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

    if len(fields) < 2:

      continue

    (key, val) = map(lambda s: s.strip(), fields)

    # Note: in Xen 3, memory has changed to total_memory

    if key in ("memory", "total_memory"):

      memory_total = int(val)

    elif key == "free_memory":

      memory_free = int(val)

    elif key == "nr_cpus":

      nr_cpus = result["cpu_total"] = int(val)

    elif key == "nr_nodes":

      result["cpu_nodes"] = int(val)

    elif key == "cores_per_socket":

      cores_per_socket = int(val)

    elif key == "threads_per_core":

      threads_per_core = int(val)

    elif key == "xen_major":

      xen_major = int(val)

    elif key == "xen_minor":

      xen_minor = int(val)

  if None not in [cores_per_socket, threads_per_core, nr_cpus]:

    result["cpu_sockets"] = nr_cpus / (cores_per_socket * threads_per_core)

  if memory_free is not None:

    result["memory_free"] = memory_free

  if memory_total is not None:

    result["memory_total"] = memory_total

  if not (xen_major is None or xen_minor is None):

    result[constants.HV_NODEINFO_KEY_VERSION] = (xen_major, xen_minor)

  return result

def _MergeInstanceInfo(info, instance_list):

  """Updates node information from L{_ParseNodeInfo} with instance info.

  @type info: dict

  @param info: Result from L{_ParseNodeInfo}

  @type instance_list: list of tuples

  @param instance_list: list of instance information; one tuple per instance

  @rtype: dict

  """

  total_instmem = 0

  for (name, _, mem, vcpus, _, _) in instance_list:

    if name == _DOM0_NAME:

      info["memory_dom0"] = mem

      info["cpu_dom0"] = vcpus

    # Include Dom0 in total memory usage

    total_instmem += mem

  memory_free = info.get("memory_free")

  memory_total = info.get("memory_total")

  # Calculate memory used by hypervisor

  if None not in [memory_total, memory_free, total_instmem]:

    info["memory_hv"] = memory_total - memory_free - total_instmem

  return info

def _GetNodeInfo(info, instance_list):

  """Combines L{_MergeInstanceInfo} and L{_ParseNodeInfo}.

  @type instance_list: list of tuples

  @param instance_list: list of instance information; one tuple per instance

  """

  return _MergeInstanceInfo(_ParseNodeInfo(info), instance_list)

def _GetConfigFileDiskData(block_devices, blockdev_prefix,

                           _letters=_DISK_LETTERS):

  """Get disk directives for Xen config file.

  This method builds the xen config disk directive according to the

  given disk_template and block_devices.

  @param block_devices: list of tuples (cfdev, rldev):

      - cfdev: dict containing ganeti config disk part

      - rldev: ganeti.block.bdev.BlockDev object

  @param blockdev_prefix: a string containing blockdevice prefix,

                          e.g. "sd" for /dev/sda

  @return: string containing disk directive for xen instance config file

  """

  if len(block_devices) > len(_letters):

    raise errors.HypervisorError("Too many disks")

  disk_data = []

  for sd_suffix, (cfdev, dev_path, _) in zip(_letters, block_devices):

    sd_name = blockdev_prefix + sd_suffix

    if cfdev.mode == constants.DISK_RDWR:

      mode = "w"

    else:

      mode = "r"

    if cfdev.dev_type in constants.DTS_FILEBASED:

      driver = _FILE_DRIVER_MAP[cfdev.logical_id[0]]

    else:

      driver = "phy"

    disk_data.append("'%s:%s,%s,%s'" % (driver, dev_path, sd_name, mode))

  return disk_data

def _QuoteCpuidField(data):

  """Add quotes around the CPUID field only if necessary.

  Xen CPUID fields come in two shapes: LIBXL strings, which need quotes around

  them, and lists of XEND strings, which don't.

  @param data: Either type of parameter.

  @return: The quoted version thereof.

  """

  return "'%s'" % data if data.startswith("host") else data

class XenHypervisor(hv_base.BaseHypervisor):

  """Xen generic hypervisor interface

  This is the Xen base class used for both Xen PVM and HVM. It contains

  all the functionality that is identical for both.

  """

  CAN_MIGRATE = True

  REBOOT_RETRY_COUNT = 60

  REBOOT_RETRY_INTERVAL = 10

  _ROOT_DIR = pathutils.RUN_DIR + "/xen-hypervisor"

  _NICS_DIR = _ROOT_DIR + "/nic" # contains NICs' info

  _DIRS = [_ROOT_DIR, _NICS_DIR]

  ANCILLARY_FILES = [

    XEND_CONFIG_FILE,

    XL_CONFIG_FILE,

    VIF_BRIDGE_SCRIPT,

    ]

  ANCILLARY_FILES_OPT = [

    XL_CONFIG_FILE,

    ]

  def __init__(self, _cfgdir=None, _run_cmd_fn=None, _cmd=None):

    hv_base.BaseHypervisor.__init__(self)

    if _cfgdir is None:

      self._cfgdir = pathutils.XEN_CONFIG_DIR

    else:

      self._cfgdir = _cfgdir

    if _run_cmd_fn is None:

      self._run_cmd_fn = utils.RunCmd

    else:

      self._run_cmd_fn = _run_cmd_fn

    self._cmd = _cmd

  @staticmethod

  def _GetCommandFromHvparams(hvparams):

    """Returns the Xen command extracted from the given hvparams.

    @type hvparams: dict of strings

    @param hvparams: hypervisor parameters

    """

    if hvparams is None or constants.HV_XEN_CMD not in hvparams:

      raise errors.HypervisorError("Cannot determine xen command.")

    else:

      return hvparams[constants.HV_XEN_CMD]

  def _GetCommand(self, hvparams):

    """Returns Xen command to use.

    @type hvparams: dict of strings

    @param hvparams: hypervisor parameters

    """

    if self._cmd is None:

      cmd = XenHypervisor._GetCommandFromHvparams(hvparams)

    else:

      cmd = self._cmd

    if cmd not in constants.KNOWN_XEN_COMMANDS:

      raise errors.ProgrammerError("Unknown Xen command '%s'" % cmd)

    return cmd

  def _RunXen(self, args, hvparams):

    """Wrapper around L{utils.process.RunCmd} to run Xen command.

    @type hvparams: dict of strings

    @param hvparams: dictionary of hypervisor params

    @see: L{utils.process.RunCmd}

    """

    cmd = [self._GetCommand(hvparams)]

    cmd.extend(args)

    return self._run_cmd_fn(cmd)

  def _ConfigFileName(self, instance_name):

    """Get the config file name for an instance.

    @param instance_name: instance name

    @type instance_name: str

    @return: fully qualified path to instance config file

    @rtype: str

    """

    return utils.PathJoin(self._cfgdir, instance_name)

  @classmethod

  def _WriteNICInfoFile(cls, instance, idx, nic):

    """Write the Xen config file for the instance.

    This version of the function just writes the config file from static data.

    """

    instance_name = instance.name

    dirs = [(dname, constants.RUN_DIRS_MODE)

            for dname in cls._DIRS + [cls._InstanceNICDir(instance_name)]]

    utils.EnsureDirs(dirs)

    cfg_file = cls._InstanceNICFile(instance_name, idx)

    data = StringIO()

    data.write("TAGS=%s\n" % r"\ ".join(instance.GetTags()))

    if nic.netinfo:

      netinfo = objects.Network.FromDict(nic.netinfo)

      for k, v in netinfo.HooksDict().iteritems():

        data.write("%s=%s\n" % (k, v))

    data.write("MAC=%s\n" % nic.mac)

    if nic.ip:

      data.write("IP=%s\n" % nic.ip)

    data.write("INTERFACE_INDEX=%s\n" % str(idx))

    if nic.name:

      data.write("INTERFACE_NAME=%s\n" % nic.name)

    data.write("INTERFACE_UUID=%s\n" % nic.uuid)

    data.write("MODE=%s\n" % nic.nicparams[constants.NIC_MODE])

    data.write("LINK=%s\n" % nic.nicparams[constants.NIC_LINK])

    try:

      utils.WriteFile(cfg_file, data=data.getvalue())

    except EnvironmentError, err:

      raise errors.HypervisorError("Cannot write Xen instance configuration"

                                   " file %s: %s" % (cfg_file, err))

  @classmethod

  def _InstanceNICDir(cls, instance_name):

    """Returns the directory holding the tap device files for a given instance.

    """

    return utils.PathJoin(cls._NICS_DIR, instance_name)

  @classmethod

  def _InstanceNICFile(cls, instance_name, seq):

    """Returns the name of the file containing the tap device for a given NIC

    """

    return utils.PathJoin(cls._InstanceNICDir(instance_name), str(seq))

  @classmethod

  def _GetConfig(cls, instance, startup_memory, block_devices):

    """Build Xen configuration for an instance.

    """

    raise NotImplementedError

  def _WriteConfigFile(self, instance_name, data):

    """Write the Xen config file for the instance.

    This version of the function just writes the config file from static data.

    """

    # just in case it exists

    utils.RemoveFile(utils.PathJoin(self._cfgdir, "auto", instance_name))

    cfg_file = self._ConfigFileName(instance_name)

    try:

      utils.WriteFile(cfg_file, data=data)

    except EnvironmentError, err:

      raise errors.HypervisorError("Cannot write Xen instance configuration"

                                   " file %s: %s" % (cfg_file, err))

  def _ReadConfigFile(self, instance_name):

    """Returns the contents of the instance config file.

    """

    filename = self._ConfigFileName(instance_name)

    try:

      file_content = utils.ReadFile(filename)

    except EnvironmentError, err:

      raise errors.HypervisorError("Failed to load Xen config file: %s" % err)

    return file_content

  def _RemoveConfigFile(self, instance_name):

    """Remove the xen configuration file.

    """

    utils.RemoveFile(self._ConfigFileName(instance_name))

    try:

      shutil.rmtree(self._InstanceNICDir(instance_name))

    except OSError, err:

      if err.errno != errno.ENOENT:

        raise

  def _StashConfigFile(self, instance_name):

    """Move the Xen config file to the log directory and return its new path.

    """

    old_filename = self._ConfigFileName(instance_name)

    base = ("%s-%s" %

            (instance_name, utils.TimestampForFilename()))

    new_filename = utils.PathJoin(pathutils.LOG_XEN_DIR, base)

    utils.RenameFile(old_filename, new_filename)

    return new_filename

  def _GetInstanceList(self, include_node, hvparams):

    """Wrapper around module level L{_GetAllInstanceList}.

    @type hvparams: dict of strings

    @param hvparams: hypervisor parameters to be used on this node

    """

    return _GetAllInstanceList(lambda: self._RunXen(["list"], hvparams),

                               include_node)

  def ListInstances(self, hvparams=None):

    """Get the list of running instances.

    """

    instance_list = self._GetInstanceList(False, hvparams)

    names = [info[0] for info in instance_list]

    return names

  def GetInstanceInfo(self, instance_name, hvparams=None):

    """Get instance properties.

    @type instance_name: string

    @param instance_name: the instance name

    @type hvparams: dict of strings

    @param hvparams: the instance's hypervisor params

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

    """

    instance_list = self._GetInstanceList(instance_name == _DOM0_NAME, hvparams)

    result = None

    for data in instance_list:

      if data[0] == instance_name:

        result = data

        break

    return result

  def GetAllInstancesInfo(self, hvparams=None):

    """Get properties of all instances.

    @type hvparams: dict of strings

    @param hvparams: hypervisor parameters

    @rtype: (string, string, int, int, HypervisorInstanceState, int)

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

    """

    return self._GetInstanceList(False, hvparams)

  def _MakeConfigFile(self, instance, startup_memory, block_devices):

    """Gather configuration details and write to disk.

    See L{_GetConfig} for arguments.

    """

    buf = StringIO()

    buf.write("# Automatically generated by Ganeti. Do not edit!\n")

    buf.write("\n")

    buf.write(self._GetConfig(instance, startup_memory, block_devices))

    buf.write("\n")

    self._WriteConfigFile(instance.name, buf.getvalue())

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

    """Start an instance.

    """

    startup_memory = self._InstanceStartupMemory(instance)

    self._MakeConfigFile(instance, startup_memory, block_devices)

    cmd = ["create"]

    if startup_paused:

      cmd.append("-p")

    cmd.append(self._ConfigFileName(instance.name))

    result = self._RunXen(cmd, instance.hvparams)

    if result.failed:

      # Move the Xen configuration file to the log directory to avoid

      # leaving a stale config file behind.

      stashed_config = self._StashConfigFile(instance.name)

      raise errors.HypervisorError("Failed to start instance %s: %s (%s). Moved"

                                   " config file to %s" %

                                   (instance.name, result.fail_reason,

                                    result.output, stashed_config))

  def StopInstance(self, instance, force=False, retry=False, name=None):

    """Stop an instance.

    """

    if name is None:

      name = instance.name

    return self._StopInstance(name, force, instance.hvparams)

  def _ShutdownInstance(self, name, hvparams):

    """Shutdown an instance if the instance is running.

    @type name: string

    @param name: name of the instance to stop

    @type hvparams: dict of string

    @param hvparams: hypervisor parameters of the instance

    The '-w' flag waits for shutdown to complete which avoids the need

    to poll in the case where we want to destroy the domain

    immediately after shutdown.

    """

    instance_info = self.GetInstanceInfo(name, hvparams=hvparams)

    if instance_info is None or _IsInstanceShutdown(instance_info[4]):

      logging.info("Failed to shutdown instance %s, not running", name)

      return None

    return self._RunXen(["shutdown", "-w", name], hvparams)

  def _DestroyInstance(self, name, hvparams):

    """Destroy an instance if the instance if the instance exists.

    @type name: string

    @param name: name of the instance to destroy

    @type hvparams: dict of string

    @param hvparams: hypervisor parameters of the instance

    """

    instance_info = self.GetInstanceInfo(name, hvparams=hvparams)

    if instance_info is None:

      logging.info("Failed to destroy instance %s, does not exist", name)

      return None

    return self._RunXen(["destroy", name], hvparams)

  # Destroy a domain only if necessary

  #

  # This method checks if the domain has already been destroyed before

  # issuing the 'destroy' command.  This step is necessary to handle

  # domains created by other versions of Ganeti.  For example, an

  # instance created with 2.10 will be destroy by the

  # '_ShutdownInstance', thus not requiring an additional destroy,

  # which would cause an error if issued.  See issue 619.

  def _DestroyInstanceIfAlive(self, name, hvparams):

    instance_info = self.GetInstanceInfo(name, hvparams=hvparams)

    if instance_info is None:

      raise errors.HypervisorError("Failed to destroy instance %s, already"

                                   " destroyed" % name)

    else:

      self._DestroyInstance(name, hvparams)

  def _StopInstance(self, name, force, hvparams):

    """Stop an instance.

    @type name: string

    @param name: name of the instance to destroy

    @type force: boolean

    @param force: whether to do a "hard" stop (destroy)

    @type hvparams: dict of string

    @param hvparams: hypervisor parameters of the instance

    """

    instance_info = self.GetInstanceInfo(name, hvparams=hvparams)

    if instance_info is None:

      raise errors.HypervisorError("Failed to shutdown instance %s,"

                                   " not running" % name)

    if force:

      result = self._DestroyInstanceIfAlive(name, hvparams)

    else:

      self._ShutdownInstance(name, hvparams)

      result = self._DestroyInstanceIfAlive(name, hvparams)

    if result is not None and result.failed and \

          self.GetInstanceInfo(name, hvparams=hvparams) is not None:

      raise errors.HypervisorError("Failed to stop instance %s: %s, %s" %

                                   (name, result.fail_reason, result.output))