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"""Xen hypervisors

"""

import os

import os.path

import time

import logging

from cStringIO import StringIO

from ganeti import constants

from ganeti import errors

from ganeti import utils

from ganeti.hypervisor import hv_base

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.

  """

  REBOOT_RETRY_COUNT = 60

  REBOOT_RETRY_INTERVAL = 10

  ANCILLARY_FILES = [

    '/etc/xen/xend-config.sxp',

    '/etc/xen/scripts/vif-bridge',

    ]

  @classmethod

  def _WriteConfigFile(cls, instance, block_devices):

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

    """

    raise NotImplementedError

  @staticmethod

  def _WriteConfigFileStatic(instance_name, data):

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

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

    """

    utils.WriteFile("/etc/xen/%s" % instance_name, data=data)

  @staticmethod

  def _ReadConfigFile(instance_name):

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

    """

    try:

      file_content = utils.ReadFile("/etc/xen/%s" % instance_name)

    except EnvironmentError, err:

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

    return file_content

  @staticmethod

  def _RemoveConfigFile(instance_name):

    """Remove the xen configuration file.

    """

    utils.RemoveFile("/etc/xen/%s" % instance_name)

  @staticmethod

  def _GetXMList(include_node):

    """Return the list of running instances.

    If the include_node argument is True, then we return information

    for dom0 also, otherwise we filter that from the return value.

    @return: list of (name, id, memory, vcpus, state, time spent)

    """

    for dummy in range(5):

      result = utils.RunCmd(["xm", "list"])

      if not result.failed:

        break

      logging.error("xm list failed (%s): %s", result.fail_reason,

                    result.output)

      time.sleep(1)

    if result.failed:

      raise errors.HypervisorError("xm list failed, retries"

                                   " exceeded (%s): %s" %

                                   (result.fail_reason, result.output))

    # skip over the heading

    lines = result.stdout.splitlines()[1:]

    result = []

    for line in lines:

      # 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 output of xm list,"

                                     " line: %s" % line)

      try:

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

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

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

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

      except ValueError, err:

        raise errors.HypervisorError("Can't parse output of xm list,"

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

      # skip the Domain-0 (optional)

      if include_node or data[0] != 'Domain-0':

        result.append(data)

    return result

  def ListInstances(self):

    """Get the list of running instances.

    """

    xm_list = self._GetXMList(False)

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

    return names

  def GetInstanceInfo(self, instance_name):

    """Get instance properties.

    @param instance_name: the instance name

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

    """

    xm_list = self._GetXMList(instance_name=="Domain-0")

    result = None

    for data in xm_list:

      if data[0] == instance_name:

        result = data

        break

    return result

  def GetAllInstancesInfo(self):

    """Get properties of all instances.

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

    """

    xm_list = self._GetXMList(False)

    return xm_list

  def StartInstance(self, instance, block_devices):

    """Start an instance.

    """

    self._WriteConfigFile(instance, block_devices)

    result = utils.RunCmd(["xm", "create", instance.name])

    if result.failed:

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

                                   (instance.name, result.fail_reason,

                                    result.output))

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

    """Stop an instance.

    """

    self._RemoveConfigFile(instance.name)

    if force:

      command = ["xm", "destroy", instance.name]

    else:

      command = ["xm", "shutdown", instance.name]

    result = utils.RunCmd(command)

    if result.failed:

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

                                   (instance.name, result.fail_reason,

                                    result.output))

  def RebootInstance(self, instance):

    """Reboot an instance.

    """

    ini_info = self.GetInstanceInfo(instance.name)

    result = utils.RunCmd(["xm", "reboot", instance.name])

    if result.failed:

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

                                   (instance.name, result.fail_reason,

                                    result.output))

    done = False

    retries = self.REBOOT_RETRY_COUNT

    while retries > 0:

      new_info = self.GetInstanceInfo(instance.name)

      # check if the domain ID has changed or the run time has

      # decreased

      if new_info[1] != ini_info[1] or new_info[5] < ini_info[5]:

        done = True

        break

      time.sleep(self.REBOOT_RETRY_INTERVAL)

      retries -= 1

    if not done:

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

                                   " did not reboot in the expected interval" %

                                   (instance.name, ))

  def GetNodeInfo(self):

    """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

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

          - 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

    """

    # note: in xen 3, memory has changed to total_memory

    result = utils.RunCmd(["xm", "info"])

    if result.failed:

      logging.error("Can't run 'xm info' (%s): %s", result.fail_reason,

                    result.output)

      return None

    xmoutput = result.stdout.splitlines()

    result = {}

    cores_per_socket = threads_per_core = nr_cpus = None

    for line in xmoutput:

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

      if len(splitfields) > 1:

        key = splitfields[0].strip()

        val = splitfields[1].strip()

        if key == 'memory' or key == 'total_memory':

          result['memory_total'] = int(val)

        elif key == 'free_memory':

          result['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)

    if (cores_per_socket is not None and

        threads_per_core is not None and nr_cpus is not None):

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

    dom0_info = self.GetInstanceInfo("Domain-0")

    if dom0_info is not None:

      result['memory_dom0'] = dom0_info[2]

    return result

  @classmethod

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

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

    """

    return "xm console %s" % instance.name

  def Verify(self):

    """Verify the hypervisor.

    For Xen, this verifies that the xend process is running.

    """

    result = utils.RunCmd(["xm", "info"])

    if result.failed:

      return "'xm info' failed: %s, %s" % (result.fail_reason, result.output)

  @staticmethod

  def _GetConfigFileDiskData(disk_template, block_devices):

    """Get disk directive for xen config file.

    This method builds the xen config disk directive according to the

    given disk_template and block_devices.

    @param disk_template: string containing instance disk template

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

        - cfdev: dict containing ganeti config disk part

        - rldev: ganeti.bdev.BlockDev object

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

    """

    FILE_DRIVER_MAP = {

      constants.FD_LOOP: "file",

      constants.FD_BLKTAP: "tap:aio",

      }

    disk_data = []

    if len(block_devices) > 24:

      # 'z' - 'a' = 24

      raise errors.HypervisorError("Too many disks")

    # FIXME: instead of this hardcoding here, each of PVM/HVM should

    # directly export their info (currently HVM will just sed this info)

    namespace = ["sd" + chr(i + ord('a')) for i in range(24)]

    for sd_name, (cfdev, dev_path) in zip(namespace, block_devices):

      if cfdev.mode == constants.DISK_RDWR:

        mode = "w"

      else:

        mode = "r"

      if cfdev.dev_type == constants.LD_FILE:

        line = "'%s:%s,%s,%s'" % (FILE_DRIVER_MAP[cfdev.physical_id[0]],

                                  dev_path, sd_name, mode)

      else:

        line = "'phy:%s,%s,%s'" % (dev_path, sd_name, mode)

      disk_data.append(line)

    return disk_data

  def MigrationInfo(self, instance):

    """Get instance information to perform a migration.

    @type instance: L{objects.Instance}

    @param instance: instance to be migrated

    @rtype: string

    @return: content of the xen config file

    """

    return self._ReadConfigFile(instance.name)

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

    """Prepare to accept an instance.

    @type instance: L{objects.Instance}

    @param instance: instance to be accepted

    @type info: string

    @param info: content of the xen config file on the source node

    @type target: string

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

    """

    pass

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

    """Finalize an instance migration.

    After a successful migration we write the xen config file.

    We do nothing on a failure, as we did not change anything at accept time.

    @type instance: L{objects.Instance}

    @param instance: instance whose migration is being aborted

    @type info: string

    @param info: content of the xen config file on the source node

    @type success: boolean

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

    """

    if success:

      self._WriteConfigFileStatic(instance.name, info)

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

    """Migrate an instance to a target node.

    The migration will not be attempted if the instance is not

    currently running.

    @type instance: string

    @param instance: instance name

    @type target: string

    @param target: ip address of the target node

    @type live: boolean

    @param live: perform a live migration

    """

    if self.GetInstanceInfo(instance) is None:

      raise errors.HypervisorError("Instance not running, cannot migrate")

    args = ["xm", "migrate"]

    if live:

      args.append("-l")

    args.extend([instance, target])

    result = utils.RunCmd(args)

    if result.failed:

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

                                   (instance, result.output))

    # remove old xen file after migration succeeded

    try:

      self._RemoveConfigFile(instance)

    except EnvironmentError:

      logging.exception("Failure while removing instance config file")

  @classmethod

  def PowercycleNode(cls):

    """Xen-specific powercycle.

    This first does a Linux reboot (which triggers automatically a Xen

    reboot), and if that fails it tries to do a Xen reboot. The reason

    we don't try a Xen reboot first is that the xen reboot launches an

    external command which connects to the Xen hypervisor, and that

    won't work in case the root filesystem is broken and/or the xend

    daemon is not working.

    """

    try:

      cls.LinuxPowercycle()

    finally:

      utils.RunCmd(["xm", "debug", "R"])

class XenPvmHypervisor(XenHypervisor):

  """Xen PVM hypervisor interface"""

  PARAMETERS = {

    constants.HV_KERNEL_PATH: hv_base.REQ_FILE_CHECK,

    constants.HV_INITRD_PATH: hv_base.OPT_FILE_CHECK,

    constants.HV_ROOT_PATH: hv_base.REQUIRED_CHECK,

    constants.HV_KERNEL_ARGS: hv_base.NO_CHECK,

    }

  @classmethod

  def _WriteConfigFile(cls, instance, block_devices):

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

    """

    hvp = instance.hvparams

    config = StringIO()

    config.write("# this is autogenerated by Ganeti, please do not edit\n#\n")

    # kernel handling

    kpath = hvp[constants.HV_KERNEL_PATH]

    config.write("kernel = '%s'\n" % kpath)

    # initrd handling

    initrd_path = hvp[constants.HV_INITRD_PATH]

    if initrd_path:

      config.write("ramdisk = '%s'\n" % initrd_path)

    # rest of the settings

    config.write("memory = %d\n" % instance.beparams[constants.BE_MEMORY])

    config.write("vcpus = %d\n" % instance.beparams[constants.BE_VCPUS])

    config.write("name = '%s'\n" % instance.name)

    vif_data = []

    for nic in instance.nics:

      nic_str = "mac=%s, bridge=%s" % (nic.mac, nic.bridge)

      ip = getattr(nic, "ip", None)

      if ip is not None:

        nic_str += ", ip=%s" % ip

      vif_data.append("'%s'" % nic_str)

    config.write("vif = [%s]\n" % ",".join(vif_data))

    config.write("disk = [%s]\n" % ",".join(

                 cls._GetConfigFileDiskData(instance.disk_template,

                                            block_devices)))

    config.write("root = '%s'\n" % hvp[constants.HV_ROOT_PATH])

    config.write("on_poweroff = 'destroy'\n")

    config.write("on_reboot = 'restart'\n")

    config.write("on_crash = 'restart'\n")

    config.write("extra = '%s'\n" % hvp[constants.HV_KERNEL_ARGS])

    # just in case it exists

    utils.RemoveFile("/etc/xen/auto/%s" % instance.name)

    try:

      utils.WriteFile("/etc/xen/%s" % instance.name, data=config.getvalue())

    except EnvironmentError, err:

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

                                   " file /etc/xen/%s: %s" %

                                   (instance.name, err))

    return True

class XenHvmHypervisor(XenHypervisor):

  """Xen HVM hypervisor interface"""

  ANCILLARY_FILES = XenHypervisor.ANCILLARY_FILES + \

    [constants.VNC_PASSWORD_FILE]

  PARAMETERS = {

    constants.HV_ACPI: hv_base.NO_CHECK,

    constants.HV_BOOT_ORDER: (True, ) + \

    (lambda x: x and len(x.strip("acdn")) == 0,

     "Invalid boot order specified, must be one or more of [acdn]",

     None, None),

    constants.HV_CDROM_IMAGE_PATH: hv_base.OPT_FILE_CHECK,

    constants.HV_DISK_TYPE: \

    hv_base.ParamInSet(True, constants.HT_HVM_VALID_DISK_TYPES),

    constants.HV_NIC_TYPE: \

    hv_base.ParamInSet(True, constants.HT_HVM_VALID_NIC_TYPES),

    constants.HV_PAE: hv_base.NO_CHECK,

    constants.HV_VNC_BIND_ADDRESS: \

    (False, utils.IsValidIP,

     "VNC bind address is not a valid IP address", None, None),

    constants.HV_KERNEL_PATH: hv_base.REQ_FILE_CHECK,

    constants.HV_DEVICE_MODEL: hv_base.REQ_FILE_CHECK,

    }

  @classmethod

  def _WriteConfigFile(cls, instance, block_devices):

    """Create a Xen 3.1 HVM config file.

    """

    hvp = instance.hvparams

    config = StringIO()

    config.write("# this is autogenerated by Ganeti, please do not edit\n#\n")

    # kernel handling

    kpath = hvp[constants.HV_KERNEL_PATH]

    config.write("kernel = '%s'\n" % kpath)

    config.write("builder = 'hvm'\n")

    config.write("memory = %d\n" % instance.beparams[constants.BE_MEMORY])

    config.write("vcpus = %d\n" % instance.beparams[constants.BE_VCPUS])

    config.write("name = '%s'\n" % instance.name)

    if hvp[constants.HV_PAE]:

      config.write("pae = 1\n")

    else:

      config.write("pae = 0\n")

    if hvp[constants.HV_ACPI]:

      config.write("acpi = 1\n")

    else:

      config.write("acpi = 0\n")

    config.write("apic = 1\n")

    config.write("device_model = '%s'\n" % hvp[constants.HV_DEVICE_MODEL])

    config.write("boot = '%s'\n" % hvp[constants.HV_BOOT_ORDER])

    config.write("sdl = 0\n")

    config.write("usb = 1\n")

    config.write("usbdevice = 'tablet'\n")

    config.write("vnc = 1\n")

    if hvp[constants.HV_VNC_BIND_ADDRESS] is None:

      config.write("vnclisten = '%s'\n" % constants.VNC_DEFAULT_BIND_ADDRESS)

    else:

      config.write("vnclisten = '%s'\n" % hvp[constants.HV_VNC_BIND_ADDRESS])

    if instance.network_port > constants.VNC_BASE_PORT:

      display = instance.network_port - constants.VNC_BASE_PORT

      config.write("vncdisplay = %s\n" % display)

      config.write("vncunused = 0\n")

    else:

      config.write("# vncdisplay = 1\n")

      config.write("vncunused = 1\n")

    try:

      password = utils.ReadFile(constants.VNC_PASSWORD_FILE)

    except EnvironmentError, err:

      raise errors.HypervisorError("Failed to open VNC password file %s: %s" %

                                   (constants.VNC_PASSWORD_FILE, err))

    config.write("vncpasswd = '%s'\n" % password.rstrip())

    config.write("serial = 'pty'\n")

    config.write("localtime = 1\n")

    vif_data = []

    nic_type = hvp[constants.HV_NIC_TYPE]

    if nic_type is None:

      # ensure old instances don't change

      nic_type_str = ", type=ioemu"

    elif nic_type == constants.HT_NIC_PARAVIRTUAL:

      nic_type_str = ", type=paravirtualized"

    else:

      nic_type_str = ", model=%s, type=ioemu" % nic_type

    for nic in instance.nics:

      nic_str = "mac=%s, bridge=%s%s" % (nic.mac, nic.bridge, nic_type_str)

      ip = getattr(nic, "ip", None)

      if ip is not None:

        nic_str += ", ip=%s" % ip

      vif_data.append("'%s'" % nic_str)

    config.write("vif = [%s]\n" % ",".join(vif_data))

    disk_data = cls._GetConfigFileDiskData(instance.disk_template,

                                            block_devices)

    disk_type = hvp[constants.HV_DISK_TYPE]

    if disk_type in (None, constants.HT_DISK_IOEMU):

      replacement = ",ioemu:hd"

    else:

      replacement = ",hd"

    disk_data = [line.replace(",sd", replacement) for line in disk_data]

    iso_path = hvp[constants.HV_CDROM_IMAGE_PATH]

    if iso_path:

      iso = "'file:%s,hdc:cdrom,r'" % iso_path

      disk_data.append(iso)

    config.write("disk = [%s]\n" % (",".join(disk_data)))

    config.write("on_poweroff = 'destroy'\n")

    config.write("on_reboot = 'restart'\n")

    config.write("on_crash = 'restart'\n")

    # just in case it exists

    utils.RemoveFile("/etc/xen/auto/%s" % instance.name)

    try:

      utils.WriteFile("/etc/xen/%s" % instance.name,

                      data=config.getvalue())

    except EnvironmentError, err:

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

                                   " file /etc/xen/%s: %s" %

                                   (instance.name, err))

    return True