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"""Xen hypervisors

"""

import os

import os.path

import time

from cStringIO import StringIO

from ganeti import constants

from ganeti import errors

from ganeti import logger

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.

  """

  @staticmethod

  def _WriteConfigFile(instance, block_devices, extra_args):

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

    """

    raise NotImplementedError

  @staticmethod

  def _RemoveConfigFile(instance):

    """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.

    The return value is a list of (name, id, memory, vcpus, state, time spent)

    """

    for dummy in range(5):

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

      if not result.failed:

        break

      logger.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.

    Args:

      instance_name: the instance name

    Returns:

      (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.

    Returns:

      [(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)

    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.

    The return value is a dict, which has to have the following items:

      (all 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:

      logger.Error("Can't run 'xm info': %s" % result.fail_reason)

      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

  @staticmethod

  def GetShellCommandForConsole(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.

    Args:

      disk_template: String containing instance disk template

      block_devices: List[tuple1,tuple2,...]

        tuple: (cfdev, rldev)

          cfdev: dict containing ganeti config disk part

          rldev: ganeti.bdev.BlockDev object

    Returns:

      String containing disk directive for xen instance config file

    """

    FILE_DRIVER_MAP = {

      constants.FD_LOOP: "file",

      constants.FD_BLKTAP: "tap:aio",

      }

    disk_data = []

    for cfdev, rldev in block_devices:

      if cfdev.dev_type == constants.LD_FILE:

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

                                 rldev.dev_path, cfdev.iv_name)

      else:

        line = "'phy:%s,%s,w'" % (rldev.dev_path, cfdev.iv_name)

      disk_data.append(line)

    return disk_data

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

    """Migrate an instance to a target node.

    Arguments:

      - instance: the name of the instance

      - target: the ip of the target node

      - live: whether to do live migration or not

    Returns: none, errors will be signaled by exception.

    The migration will not be attempted if the instance is not

    currently running.

    """

    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))

class XenPvmHypervisor(XenHypervisor):

  """Xen PVM hypervisor interface"""

  @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

    if instance.kernel_path in (None, constants.VALUE_DEFAULT):

      kpath = constants.XEN_KERNEL

    else:

      if not os.path.exists(instance.kernel_path):

        raise errors.HypervisorError("The kernel %s for instance %s is"

                                     " missing" % (instance.kernel_path,

                                                   instance.name))

      kpath = instance.kernel_path

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

    # initrd handling

    if instance.initrd_path in (None, constants.VALUE_DEFAULT):

      if os.path.exists(constants.XEN_INITRD):

        initrd_path = constants.XEN_INITRD

      else:

        initrd_path = None

    elif instance.initrd_path == constants.VALUE_NONE:

      initrd_path = None

    else:

      if not os.path.exists(instance.initrd_path):

        raise errors.HypervisorError("The initrd %s for instance %s is"

                                     " missing" % (instance.initrd_path,

                                                   instance.name))

      initrd_path = instance.initrd_path

    if initrd_path:

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

    # rest of the settings

    config.write("memory = %d\n" % instance.memory)

    config.write("vcpus = %d\n" % instance.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 = '/dev/sda ro'\n")

    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:

      f = open("/etc/xen/%s" % instance.name, "w")

      try:

        f.write(config.getvalue())

      finally:

        f.close()

    except IOError, err:

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

                               " file /etc/xen/%s: %s" % (instance.name, err))

    return True

class XenHvmHypervisor(XenHypervisor):

  """Xen HVM hypervisor interface"""

  @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.memory)

    config.write("vcpus = %d\n" % instance.vcpus)

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

    if instance.hvm_pae:

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

    else:

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

    if instance.hvm_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.hvm_boot_order is None:

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

    else:

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

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

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

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

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

    if instance.vnc_bind_address is None:

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

    else:

      config.write("vnclisten = '%s'\n" % instance.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_file = open(constants.VNC_PASSWORD_FILE, "r")

      try:

        password = password_file.readline()

      finally:

        password_file.close()

    except IOError:

      raise errors.OpExecError("failed to open VNC password file %s " %

                               constants.VNC_PASSWORD_FILE)

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

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

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

    vif_data = []

    for nic in instance.nics:

      if instance.hvm_nic_type is None: # ensure old instances don't change

        nic_type = ", type=ioemu"

      elif instance.hvm_nic_type == constants.HT_HVM_DEV_PARAVIRTUAL:

        nic_type = ", type=paravirtualized"

      else:

        nic_type = ", model=%s, type=ioemu" % instance.hvm_nic_type

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

      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)

    if ((instance.hvm_disk_type is None) or

        (instance.hvm_disk_type == constants.HT_HVM_DEV_IOEMU)):

      replacement = ",ioemu:hd"

    else:

      replacement = ",hd"

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

    if instance.hvm_cdrom_image_path is not None:

      iso = "'file:%s,hdc:cdrom,r'" % (instance.hvm_cdrom_image_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:

      f = open("/etc/xen/%s" % instance.name, "w")

      try:

        f.write(config.getvalue())

      finally:

        f.close()

    except IOError, err:

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

                               " file /etc/xen/%s: %s" % (instance.name, err))

    return True