Synnefo » snf-ganeti

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# Copyright (C) 2006, 2007 Google Inc.

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# This program is free software; you can redistribute it and/or modify

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# This program is distributed in the hope that it will be useful, but

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# 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

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"""Module implementing the logic behind the cluster operations

This module implements the logic for doing operations in the cluster. There

are two kinds of classes defined:

  - logical units, which know how to deal with their specific opcode only

  - the processor, which dispatches the opcodes to their logical units

"""

import logging

from ganeti import opcodes

from ganeti import constants

from ganeti import errors

from ganeti import rpc

from ganeti import cmdlib

from ganeti import locking

class Processor(object):

  """Object which runs OpCodes"""

  DISPATCH_TABLE = {

    # Cluster

    opcodes.OpDestroyCluster: cmdlib.LUDestroyCluster,

    opcodes.OpQueryClusterInfo: cmdlib.LUQueryClusterInfo,

    opcodes.OpVerifyCluster: cmdlib.LUVerifyCluster,

    opcodes.OpQueryConfigValues: cmdlib.LUQueryConfigValues,

    opcodes.OpRenameCluster: cmdlib.LURenameCluster,

    opcodes.OpVerifyDisks: cmdlib.LUVerifyDisks,

    opcodes.OpSetClusterParams: cmdlib.LUSetClusterParams,

    opcodes.OpRedistributeConfig: cmdlib.LURedistributeConfig,

    # node lu

    opcodes.OpAddNode: cmdlib.LUAddNode,

    opcodes.OpQueryNodes: cmdlib.LUQueryNodes,

    opcodes.OpQueryNodeVolumes: cmdlib.LUQueryNodeVolumes,

    opcodes.OpRemoveNode: cmdlib.LURemoveNode,

    opcodes.OpSetNodeParams: cmdlib.LUSetNodeParams,

    opcodes.OpPowercycleNode: cmdlib.LUPowercycleNode,

    # instance lu

    opcodes.OpCreateInstance: cmdlib.LUCreateInstance,

    opcodes.OpReinstallInstance: cmdlib.LUReinstallInstance,

    opcodes.OpRemoveInstance: cmdlib.LURemoveInstance,

    opcodes.OpRenameInstance: cmdlib.LURenameInstance,

    opcodes.OpActivateInstanceDisks: cmdlib.LUActivateInstanceDisks,

    opcodes.OpShutdownInstance: cmdlib.LUShutdownInstance,

    opcodes.OpStartupInstance: cmdlib.LUStartupInstance,

    opcodes.OpRebootInstance: cmdlib.LURebootInstance,

    opcodes.OpDeactivateInstanceDisks: cmdlib.LUDeactivateInstanceDisks,

    opcodes.OpReplaceDisks: cmdlib.LUReplaceDisks,

    opcodes.OpFailoverInstance: cmdlib.LUFailoverInstance,

    opcodes.OpMigrateInstance: cmdlib.LUMigrateInstance,

    opcodes.OpConnectConsole: cmdlib.LUConnectConsole,

    opcodes.OpQueryInstances: cmdlib.LUQueryInstances,

    opcodes.OpQueryInstanceData: cmdlib.LUQueryInstanceData,

    opcodes.OpSetInstanceParams: cmdlib.LUSetInstanceParams,

    opcodes.OpGrowDisk: cmdlib.LUGrowDisk,

    # os lu

    opcodes.OpDiagnoseOS: cmdlib.LUDiagnoseOS,

    # exports lu

    opcodes.OpQueryExports: cmdlib.LUQueryExports,

    opcodes.OpExportInstance: cmdlib.LUExportInstance,

    opcodes.OpRemoveExport: cmdlib.LURemoveExport,

    # tags lu

    opcodes.OpGetTags: cmdlib.LUGetTags,

    opcodes.OpSearchTags: cmdlib.LUSearchTags,

    opcodes.OpAddTags: cmdlib.LUAddTags,

    opcodes.OpDelTags: cmdlib.LUDelTags,

    # test lu

    opcodes.OpTestDelay: cmdlib.LUTestDelay,

    opcodes.OpTestAllocator: cmdlib.LUTestAllocator,

    }

  def __init__(self, context):

    """Constructor for Processor

    Args:

     - feedback_fn: the feedback function (taking one string) to be run when

                    interesting events are happening

    """

    self.context = context

    self._feedback_fn = None

    self.exclusive_BGL = False

    self.rpc = rpc.RpcRunner(context.cfg)

  def _ExecLU(self, lu):

    """Logical Unit execution sequence.

    """

    write_count = self.context.cfg.write_count

    lu.CheckPrereq()

    hm = HooksMaster(self.rpc.call_hooks_runner, self, lu)

    h_results = hm.RunPhase(constants.HOOKS_PHASE_PRE)

    lu.HooksCallBack(constants.HOOKS_PHASE_PRE, h_results,

                     self._feedback_fn, None)

    if getattr(lu.op, "dry_run", False):

      # in this mode, no post-hooks are run, and the config is not

      # written (as it might have been modified by another LU, and we

      # shouldn't do writeout on behalf of other threads

      self.LogInfo("dry-run mode requested, not actually executing"

                   " the operation")

      return lu.dry_run_result

    try:

      result = lu.Exec(self._feedback_fn)

      h_results = hm.RunPhase(constants.HOOKS_PHASE_POST)

      result = lu.HooksCallBack(constants.HOOKS_PHASE_POST, h_results,

                                self._feedback_fn, result)

    finally:

      # FIXME: This needs locks if not lu_class.REQ_BGL

      if write_count != self.context.cfg.write_count:

        hm.RunConfigUpdate()

    return result

  def _LockAndExecLU(self, lu, level):

    """Execute a Logical Unit, with the needed locks.

    This is a recursive function that starts locking the given level, and

    proceeds up, till there are no more locks to acquire. Then it executes the

    given LU and its opcodes.

    """

    adding_locks = level in lu.add_locks

    acquiring_locks = level in lu.needed_locks

    if level not in locking.LEVELS:

      if callable(self._run_notifier):

        self._run_notifier()

      result = self._ExecLU(lu)

    elif adding_locks and acquiring_locks:

      # We could both acquire and add locks at the same level, but for now we

      # don't need this, so we'll avoid the complicated code needed.

      raise NotImplementedError(

        "Can't declare locks to acquire when adding others")

    elif adding_locks or acquiring_locks:

      lu.DeclareLocks(level)

      share = lu.share_locks[level]

      if acquiring_locks:

        needed_locks = lu.needed_locks[level]

        lu.acquired_locks[level] = self.context.glm.acquire(level,

                                                            needed_locks,

                                                            shared=share)

      else: # adding_locks

        add_locks = lu.add_locks[level]

        lu.remove_locks[level] = add_locks

        try:

          self.context.glm.add(level, add_locks, acquired=1, shared=share)

        except errors.LockError:

          raise errors.OpPrereqError(

            "Coudn't add locks (%s), probably because of a race condition"

            " with another job, who added them first" % add_locks)

      try:

        try:

          if adding_locks:

            lu.acquired_locks[level] = add_locks

          result = self._LockAndExecLU(lu, level + 1)

        finally:

          if level in lu.remove_locks:

            self.context.glm.remove(level, lu.remove_locks[level])

      finally:

        if self.context.glm.is_owned(level):

          self.context.glm.release(level)

    else:

      result = self._LockAndExecLU(lu, level + 1)

    return result

  def ExecOpCode(self, op, feedback_fn, run_notifier):

    """Execute an opcode.

    @type op: an OpCode instance

    @param op: the opcode to be executed

    @type feedback_fn: a function that takes a single argument

    @param feedback_fn: this function will be used as feedback from the LU

                        code to the end-user

    @type run_notifier: callable (no arguments) or None

    @param run_notifier:  this function (if callable) will be called when

                          we are about to call the lu's Exec() method, that

                          is, after we have aquired all locks

    """

    if not isinstance(op, opcodes.OpCode):

      raise errors.ProgrammerError("Non-opcode instance passed"

                                   " to ExecOpcode")

    self._feedback_fn = feedback_fn

    self._run_notifier = run_notifier

    lu_class = self.DISPATCH_TABLE.get(op.__class__, None)

    if lu_class is None:

      raise errors.OpCodeUnknown("Unknown opcode")

    # Acquire the Big Ganeti Lock exclusively if this LU requires it, and in a

    # shared fashion otherwise (to prevent concurrent run with an exclusive LU.

    self.context.glm.acquire(locking.LEVEL_CLUSTER, [locking.BGL],

                             shared=not lu_class.REQ_BGL)

    try:

      self.exclusive_BGL = lu_class.REQ_BGL

      lu = lu_class(self, op, self.context, self.rpc)

      lu.ExpandNames()

      assert lu.needed_locks is not None, "needed_locks not set by LU"

      result = self._LockAndExecLU(lu, locking.LEVEL_INSTANCE)

    finally:

      self.context.glm.release(locking.LEVEL_CLUSTER)

      self.exclusive_BGL = False

    return result

  def LogStep(self, current, total, message):

    """Log a change in LU execution progress.

    """

    logging.debug("Step %d/%d %s", current, total, message)

    self._feedback_fn("STEP %d/%d %s" % (current, total, message))

  def LogWarning(self, message, *args, **kwargs):

    """Log a warning to the logs and the user.

    The optional keyword argument is 'hint' and can be used to show a

    hint to the user (presumably related to the warning). If the

    message is empty, it will not be printed at all, allowing one to

    show only a hint.

    """

    assert not kwargs or (len(kwargs) == 1 and "hint" in kwargs), \

           "Invalid keyword arguments for LogWarning (%s)" % str(kwargs)

    if args:

      message = message % tuple(args)

    if message:

      logging.warning(message)

      self._feedback_fn(" - WARNING: %s" % message)

    if "hint" in kwargs:

      self._feedback_fn("      Hint: %s" % kwargs["hint"])

  def LogInfo(self, message, *args):

    """Log an informational message to the logs and the user.

    """

    if args:

      message = message % tuple(args)

    logging.info(message)

    self._feedback_fn(" - INFO: %s" % message)

class HooksMaster(object):

  """Hooks master.

  This class distributes the run commands to the nodes based on the

  specific LU class.

  In order to remove the direct dependency on the rpc module, the

  constructor needs a function which actually does the remote

  call. This will usually be rpc.call_hooks_runner, but any function

  which behaves the same works.

  """

  def __init__(self, callfn, proc, lu):

    self.callfn = callfn

    self.proc = proc

    self.lu = lu

    self.op = lu.op

    self.env, node_list_pre, node_list_post = self._BuildEnv()

    self.node_list = {constants.HOOKS_PHASE_PRE: node_list_pre,

                      constants.HOOKS_PHASE_POST: node_list_post}

  def _BuildEnv(self):

    """Compute the environment and the target nodes.

    Based on the opcode and the current node list, this builds the

    environment for the hooks and the target node list for the run.

    """

    env = {

      "PATH": "/sbin:/bin:/usr/sbin:/usr/bin",

      "GANETI_HOOKS_VERSION": constants.HOOKS_VERSION,

      "GANETI_OP_CODE": self.op.OP_ID,

      "GANETI_OBJECT_TYPE": self.lu.HTYPE,

      "GANETI_DATA_DIR": constants.DATA_DIR,

      }

    if self.lu.HPATH is not None:

      lu_env, lu_nodes_pre, lu_nodes_post = self.lu.BuildHooksEnv()

      if lu_env:

        for key in lu_env:

          env["GANETI_" + key] = lu_env[key]

    else:

      lu_nodes_pre = lu_nodes_post = []

    return env, frozenset(lu_nodes_pre), frozenset(lu_nodes_post)

  def _RunWrapper(self, node_list, hpath, phase):

    """Simple wrapper over self.callfn.

    This method fixes the environment before doing the rpc call.

    """

    env = self.env.copy()

    env["GANETI_HOOKS_PHASE"] = phase

    env["GANETI_HOOKS_PATH"] = hpath

    if self.lu.cfg is not None:

      env["GANETI_CLUSTER"] = self.lu.cfg.GetClusterName()

      env["GANETI_MASTER"] = self.lu.cfg.GetMasterNode()

    env = dict([(str(key), str(val)) for key, val in env.iteritems()])

    return self.callfn(node_list, hpath, phase, env)

  def RunPhase(self, phase):

    """Run all the scripts for a phase.

    This is the main function of the HookMaster.

    @param phase: one of L{constants.HOOKS_PHASE_POST} or

        L{constants.HOOKS_PHASE_PRE}; it denotes the hooks phase

    @return: the processed results of the hooks multi-node rpc call

    @raise errors.HooksFailure: on communication failure to the nodes

    """

    if not self.node_list[phase]:

      # empty node list, we should not attempt to run this as either

      # we're in the cluster init phase and the rpc client part can't

      # even attempt to run, or this LU doesn't do hooks at all

      return

    hpath = self.lu.HPATH

    results = self._RunWrapper(self.node_list[phase], hpath, phase)

    if phase == constants.HOOKS_PHASE_PRE:

      errs = []

      if not results:

        raise errors.HooksFailure("Communication failure")

      for node_name in results:

        res = results[node_name]

        if res.offline:

          continue

        msg = res.RemoteFailMsg()

        if msg:

          self.proc.LogWarning("Communication failure to node %s: %s",

                               node_name, msg)

          continue

        for script, hkr, output in res.payload:

          if hkr == constants.HKR_FAIL:

            errs.append((node_name, script, output))

      if errs:

        raise errors.HooksAbort(errs)

    return results

  def RunConfigUpdate(self):

    """Run the special configuration update hook

    This is a special hook that runs only on the master after each

    top-level LI if the configuration has been updated.

    """

    phase = constants.HOOKS_PHASE_POST

    hpath = constants.HOOKS_NAME_CFGUPDATE

    nodes = [self.lu.cfg.GetMasterNode()]

    self._RunWrapper(nodes, hpath, phase)