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"""Module doing node maintenance for Ganeti watcher.

"""

import logging

from ganeti import constants

from ganeti import errors

from ganeti import hypervisor

from ganeti import netutils

from ganeti import ssconf

from ganeti import utils

from ganeti import confd

from ganeti.block import drbd

import ganeti.confd.client # pylint: disable=W0611

class NodeMaintenance(object):

  """Talks to confd daemons and possible shutdown instances/drbd devices.

  """

  def __init__(self):

    self.store_cb = confd.client.StoreResultCallback()

    self.filter_cb = confd.client.ConfdFilterCallback(self.store_cb)

    self.confd_client = confd.client.GetConfdClient(self.filter_cb)

  @staticmethod

  def ShouldRun():

    """Checks whether node maintenance should run.

    """

    try:

      return ssconf.SimpleStore().GetMaintainNodeHealth()

    except errors.ConfigurationError, err:

      logging.error("Configuration error, not activating node maintenance: %s",

                    err)

      return False

  @staticmethod

  def GetRunningInstances():

    """Compute list of hypervisor/running instances.

    """

    hyp_list = ssconf.SimpleStore().GetHypervisorList()

    results = []

    for hv_name in hyp_list:

      try:

        hv = hypervisor.GetHypervisor(hv_name)

        ilist = hv.ListInstances()

        results.extend([(iname, hv_name) for iname in ilist])

      except: # pylint: disable=W0702

        logging.error("Error while listing instances for hypervisor %s",

                      hv_name, exc_info=True)

    return results

  @staticmethod

  def GetUsedDRBDs():

    """Get list of used DRBD minors.

    """

    return drbd.DRBD8.GetUsedDevs()

  @classmethod

  def DoMaintenance(cls, role):

    """Maintain the instance list.

    """

    if role == constants.CONFD_NODE_ROLE_OFFLINE:

      inst_running = cls.GetRunningInstances()

      cls.ShutdownInstances(inst_running)

      drbd_running = cls.GetUsedDRBDs()

      cls.ShutdownDRBD(drbd_running)

    else:

      logging.debug("Not doing anything for role %s", role)

  @staticmethod

  def ShutdownInstances(inst_running):

    """Shutdown running instances.

    """

    names_running = set([i[0] for i in inst_running])

    if names_running:

      logging.info("Following instances should not be running,"

                   " shutting them down: %s", utils.CommaJoin(names_running))

      # this dictionary will collapse duplicate instance names (only

      # xen pvm/vhm) into a single key, which is fine

      i2h = dict(inst_running)

      for name in names_running:

        hv_name = i2h[name]

        hv = hypervisor.GetHypervisor(hv_name)

        hv.StopInstance(None, force=True, name=name)

  @staticmethod

  def ShutdownDRBD(drbd_running):

    """Shutdown active DRBD devices.

    """

    if drbd_running:

      logging.info("Following DRBD minors should not be active,"

                   " shutting them down: %s", utils.CommaJoin(drbd_running))

      for minor in drbd_running:

        drbd.DRBD8.ShutdownAll(minor)

  def Exec(self):

    """Check node status versus cluster desired state.

    """

    if not constants.ENABLE_CONFD:

      logging.warning("Confd use not enabled, cannot do maintenance")

      return

    my_name = netutils.Hostname.GetSysName()

    req = \

      confd.client.ConfdClientRequest(type=constants.CONFD_REQ_NODE_ROLE_BYNAME,

                                      query=my_name)

    self.confd_client.SendRequest(req, async=False, coverage=-1)

    timed_out, _, _ = self.confd_client.WaitForReply(req.rsalt)

    if not timed_out:

      # should have a valid response

      status, result = self.store_cb.GetResponse(req.rsalt)

      assert status, "Missing result but received replies"

      if not self.filter_cb.consistent[req.rsalt]:

        logging.warning("Inconsistent replies, not doing anything")

        return

      self.DoMaintenance(result.server_reply.answer)

    else:

      logging.warning("Confd query timed out, cannot do maintenance actions")