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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.

  """

  @classmethod

  def _WriteConfigFile(cls, instance, block_devices, extra_args):

    """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.stderr))

    # 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, extra_args):

    """Start an instance.

    """

    self._WriteConfigFile(instance, block_devices, extra_args)

    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" %

                                   (instance.name, result.fail_reason))

  def RebootInstance(self, instance):

    """Reboot an instance.

    """

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

    if result.failed:

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

                                   (instance.name, result.fail_reason))

  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

    """

    # 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 = {}

    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':

          result['cpu_total'] = int(val)

    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):

    """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" % result.fail_reason

  @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")

class XenPvmHypervisor(XenHypervisor):

  """Xen PVM hypervisor interface"""

  PARAMETERS = [

    constants.HV_KERNEL_PATH,

    constants.HV_INITRD_PATH,

    constants.HV_ROOT_PATH,

    ]

  @classmethod

  def CheckParameterSyntax(cls, hvparams):

    """Check the given parameters for validity.

    For the PVM hypervisor, this only check the existence of the

    kernel.

    @type hvparams:  dict

    @param hvparams: dictionary with parameter names/value

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

    """

    super(XenPvmHypervisor, cls).CheckParameterSyntax(hvparams)

    if not hvparams[constants.HV_KERNEL_PATH]:

      raise errors.HypervisorError("Need a kernel for the instance")

    if not os.path.isabs(hvparams[constants.HV_KERNEL_PATH]):

      raise errors.HypervisorError("The kernel path must be an absolute path")

    if not hvparams[constants.HV_ROOT_PATH]:

      raise errors.HypervisorError("Need a root partition for the instance")

    if hvparams[constants.HV_INITRD_PATH]:

      if not os.path.isabs(hvparams[constants.HV_INITRD_PATH]):

        raise errors.HypervisorError("The initrd path must be an absolute path"

                                     ", if defined")

  def ValidateParameters(self, hvparams):

    """Check the given parameters for validity.

    For the PVM hypervisor, this only check the existence of the

    kernel.

    """

    super(XenPvmHypervisor, self).ValidateParameters(hvparams)

    kernel_path = hvparams[constants.HV_KERNEL_PATH]

    if not os.path.isfile(kernel_path):

      raise errors.HypervisorError("Instance kernel '%s' not found or"

                                   " not a file" % kernel_path)

    initrd_path = hvparams[constants.HV_INITRD_PATH]

    if initrd_path and not os.path.isfile(initrd_path):

      raise errors.HypervisorError("Instance initrd '%s' not found or"

                                   " not a file" % initrd_path)

  @classmethod

  def _WriteConfigFile(cls, instance, block_devices, extra_args):

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

    """

    config = StringIO()

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

    # kernel handling

    kpath = instance.hvparams[constants.HV_KERNEL_PATH]

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

    # initrd handling

    initrd_path = instance.hvparams[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)))

    rpath = instance.hvparams[constants.HV_ROOT_PATH]

    config.write("root = '%s ro'\n" % rpath)

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

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

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

    if extra_args:

      config.write("extra = '%s'\n" % extra_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"""

  PARAMETERS = [

    constants.HV_ACPI,

    constants.HV_BOOT_ORDER,

    constants.HV_CDROM_IMAGE_PATH,

    constants.HV_DISK_TYPE,

    constants.HV_NIC_TYPE,

    constants.HV_PAE,

    constants.HV_VNC_BIND_ADDRESS,

    ]

  @classmethod

  def CheckParameterSyntax(cls, hvparams):

    """Check the given parameter syntax.

    """

    super(XenHvmHypervisor, cls).CheckParameterSyntax(hvparams)

    # boot order verification

    boot_order = hvparams[constants.HV_BOOT_ORDER]

    if len(boot_order.strip("acdn")) != 0:

      raise errors.HypervisorError("Invalid boot order '%s' specified,"

                                   " must be one or more of [acdn]" %

                                   boot_order)

    # device type checks

    nic_type = hvparams[constants.HV_NIC_TYPE]

    if nic_type not in constants.HT_HVM_VALID_NIC_TYPES:

      raise errors.HypervisorError("Invalid NIC type %s specified for Xen HVM"

                                   " hypervisor" % nic_type)

    disk_type = hvparams[constants.HV_DISK_TYPE]

    if disk_type not in constants.HT_HVM_VALID_DISK_TYPES:

      raise errors.HypervisorError("Invalid disk type %s specified for Xen HVM"

                                   " hypervisor" % disk_type)

    # vnc_bind_address verification

    vnc_bind_address = hvparams[constants.HV_VNC_BIND_ADDRESS]

    if vnc_bind_address is not None:

      if not utils.IsValidIP(vnc_bind_address):

        raise errors.OpPrereqError("given VNC bind address '%s' doesn't look"

                                   " like a valid IP address" %

                                   vnc_bind_address)

    iso_path = hvparams[constants.HV_CDROM_IMAGE_PATH]

    if iso_path and not os.path.isabs(iso_path):

      raise errors.HypervisorError("The path to the HVM CDROM image must"

                                   " be an absolute path or None, not %s" %

                                   iso_path)

  def ValidateParameters(self, hvparams):

    """Check the given parameters for validity.

    For the PVM hypervisor, this only check the existence of the

    kernel.

    @type hvparams:  dict

    @param hvparams: dictionary with parameter names/value

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

    """

    super(XenHvmHypervisor, self).ValidateParameters(hvparams)

    # hvm_cdrom_image_path verification

    iso_path = hvparams[constants.HV_CDROM_IMAGE_PATH]

    if iso_path and not os.path.isfile(iso_path):

      raise errors.HypervisorError("The HVM CDROM image must either be a"

                                   " regular file or a symlink pointing to"

                                   " an existing regular file, not %s" %

                                   iso_path)

  @classmethod

  def _WriteConfigFile(cls, instance, block_devices, extra_args):

    """Create a Xen 3.1 HVM config file.

    """

    config = StringIO()

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

    config.write("kernel = '/usr/lib/xen/boot/hvmloader'\n")

    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 instance.hvparams[constants.HV_PAE]:

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

    else:

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

    if instance.hvparams[constants.HV_ACPI]:

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

    else:

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

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

    arch = os.uname()[4]

    if '64' in arch:

      config.write("device_model = '/usr/lib64/xen/bin/qemu-dm'\n")

    else:

      config.write("device_model = '/usr/lib/xen/bin/qemu-dm'\n")

    if instance.hvparams[constants.HV_BOOT_ORDER] is None:

      config.write("boot = '%s'\n" % constants.HT_HVM_DEFAULT_BOOT_ORDER)

    else:

      config.write("boot = '%s'\n" % instance.hvparams["boot_order"])

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

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

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

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

    if instance.hvparams[constants.HV_VNC_BIND_ADDRESS] is None:

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

    else:

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

                   instance.hvparams["vnc_bind_address"])

    if instance.network_port > constants.HT_HVM_VNC_BASE_PORT:

      display = instance.network_port - constants.HT_HVM_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 = instance.hvparams[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_HVM_DEV_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 = instance.hvparams[constants.HV_DISK_TYPE]

    if disk_type in (None, constants.HT_HVM_DEV_IOEMU):

      replacement = ",ioemu:hd"

    else:

      replacement = ",hd"

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

    iso_path = instance.hvparams[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")

    if extra_args:

      config.write("extra = '%s'\n" % extra_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