rapi.testutils: Add exported functions to verify opcode input/result
[ganeti-local] / lib / mcpu.py
index 6666a80..95f04e0 100644 (file)
@@ -1,7 +1,7 @@
 #
 #
 
-# Copyright (C) 2006, 2007 Google Inc.
+# Copyright (C) 2006, 2007, 2011 Google Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -35,13 +35,18 @@ import time
 from ganeti import opcodes
 from ganeti import constants
 from ganeti import errors
-from ganeti import rpc
 from ganeti import cmdlib
 from ganeti import locking
+from ganeti import utils
+from ganeti import compat
 
 
-class _LockAcquireTimeout(Exception):
-  """Internal exception to report timeouts on acquiring locks.
+_OP_PREFIX = "Op"
+_LU_PREFIX = "LU"
+
+
+class LockAcquireTimeout(Exception):
+  """Exception to report timeouts on acquiring locks.
 
   """
 
@@ -50,82 +55,61 @@ def _CalculateLockAttemptTimeouts():
   """Calculate timeouts for lock attempts.
 
   """
-  running_sum = 0
-  result = [1.0]
+  result = [constants.LOCK_ATTEMPTS_MINWAIT]
+  running_sum = result[0]
 
-  # Wait for a total of at least 150s before doing a blocking acquire
-  while sum(result) < 150.0:
+  # Wait for a total of at least LOCK_ATTEMPTS_TIMEOUT before doing a
+  # blocking acquire
+  while running_sum < constants.LOCK_ATTEMPTS_TIMEOUT:
     timeout = (result[-1] * 1.05) ** 1.25
 
-    # Cap timeout at 10 seconds. This gives other jobs a chance to run
-    # even if we're still trying to get our locks, before finally moving
-    # to a blocking acquire.
-    if timeout > 10.0:
-      timeout = 10.0
-
-    elif timeout < 0.1:
-      # Lower boundary for safety
-      timeout = 0.1
+    # Cap max timeout. This gives other jobs a chance to run even if
+    # we're still trying to get our locks, before finally moving to a
+    # blocking acquire.
+    timeout = min(timeout, constants.LOCK_ATTEMPTS_MAXWAIT)
+    # And also cap the lower boundary for safety
+    timeout = max(timeout, constants.LOCK_ATTEMPTS_MINWAIT)
 
     result.append(timeout)
+    running_sum += timeout
 
   return result
 
 
-class _LockAttemptTimeoutStrategy(object):
+class LockAttemptTimeoutStrategy(object):
   """Class with lock acquire timeout strategy.
 
   """
   __slots__ = [
-    "_attempt",
+    "_timeouts",
     "_random_fn",
-    "_start_time",
     "_time_fn",
-    "_running_timeout",
     ]
 
   _TIMEOUT_PER_ATTEMPT = _CalculateLockAttemptTimeouts()
 
-  def __init__(self, attempt=0, _time_fn=time.time, _random_fn=random.random):
+  def __init__(self, _time_fn=time.time, _random_fn=random.random):
     """Initializes this class.
 
-    @type attempt: int
-    @param attempt: Current attempt number
     @param _time_fn: Time function for unittests
     @param _random_fn: Random number generator for unittests
 
     """
     object.__init__(self)
 
-    if attempt < 0:
-      raise ValueError("Attempt must be zero or positive")
-
-    self._attempt = attempt
+    self._timeouts = iter(self._TIMEOUT_PER_ATTEMPT)
     self._time_fn = _time_fn
     self._random_fn = _random_fn
 
-    try:
-      timeout = self._TIMEOUT_PER_ATTEMPT[attempt]
-    except IndexError:
-      # No more timeouts, do blocking acquire
-      timeout = None
-
-    self._running_timeout = locking.RunningTimeout(timeout, False,
-                                                   _time_fn=_time_fn)
-
   def NextAttempt(self):
-    """Returns the strategy for the next attempt.
-
-    """
-    return _LockAttemptTimeoutStrategy(attempt=self._attempt + 1,
-                                       _time_fn=self._time_fn,
-                                       _random_fn=self._random_fn)
-
-  def CalcRemainingTimeout(self):
-    """Returns the remaining timeout.
+    """Returns the timeout for the next attempt.
 
     """
-    timeout = self._running_timeout.Remaining()
+    try:
+      timeout = self._timeouts.next()
+    except StopIteration:
+      # No more timeouts, do blocking acquire
+      timeout = None
 
     if timeout is not None:
       # Add a small variation (-/+ 5%) to timeout. This helps in situations
@@ -137,7 +121,7 @@ class _LockAttemptTimeoutStrategy(object):
     return timeout
 
 
-class OpExecCbBase:
+class OpExecCbBase: # pylint: disable=W0232
   """Base class for OpCode execution callbacks.
 
   """
@@ -154,73 +138,56 @@ class OpExecCbBase:
 
     """
 
-  def ReportLocks(self, msg):
-    """Report lock operations.
+  def CheckCancel(self):
+    """Check whether job has been cancelled.
 
     """
 
+  def SubmitManyJobs(self, jobs):
+    """Submits jobs for processing.
+
+    See L{jqueue.JobQueue.SubmitManyJobs}.
+
+    """
+    raise NotImplementedError
+
+
+def _LUNameForOpName(opname):
+  """Computes the LU name for a given OpCode name.
+
+  """
+  assert opname.startswith(_OP_PREFIX), \
+      "Invalid OpCode name, doesn't start with %s: %s" % (_OP_PREFIX, opname)
+
+  return _LU_PREFIX + opname[len(_OP_PREFIX):]
+
+
+def _ComputeDispatchTable():
+  """Computes the opcode-to-lu dispatch table.
+
+  """
+  return dict((op, getattr(cmdlib, _LUNameForOpName(op.__name__)))
+              for op in opcodes.OP_MAPPING.values()
+              if op.WITH_LU)
+
+
+def _RpcResultsToHooksResults(rpc_results):
+  """Function to convert RPC results to the format expected by HooksMaster.
+
+  @type rpc_results: dict(node: L{rpc.RpcResult})
+  @param rpc_results: RPC results
+  @rtype: dict(node: (fail_msg, offline, hooks_results))
+  @return: RPC results unpacked according to the format expected by
+    L({mcpu.HooksMaster}
+
+  """
+  return dict((node, (rpc_res.fail_msg, rpc_res.offline, rpc_res.payload))
+              for (node, rpc_res) in rpc_results.items())
+
 
 class Processor(object):
   """Object which runs OpCodes"""
-  DISPATCH_TABLE = {
-    # Cluster
-    opcodes.OpPostInitCluster: cmdlib.LUPostInitCluster,
-    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,
-    opcodes.OpRepairDiskSizes: cmdlib.LURepairDiskSizes,
-    # node lu
-    opcodes.OpAddNode: cmdlib.LUAddNode,
-    opcodes.OpQueryNodes: cmdlib.LUQueryNodes,
-    opcodes.OpQueryNodeVolumes: cmdlib.LUQueryNodeVolumes,
-    opcodes.OpQueryNodeStorage: cmdlib.LUQueryNodeStorage,
-    opcodes.OpModifyNodeStorage: cmdlib.LUModifyNodeStorage,
-    opcodes.OpRepairNodeStorage: cmdlib.LURepairNodeStorage,
-    opcodes.OpRemoveNode: cmdlib.LURemoveNode,
-    opcodes.OpSetNodeParams: cmdlib.LUSetNodeParams,
-    opcodes.OpPowercycleNode: cmdlib.LUPowercycleNode,
-    opcodes.OpEvacuateNode: cmdlib.LUEvacuateNode,
-    opcodes.OpMigrateNode: cmdlib.LUMigrateNode,
-    # 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.OpRecreateInstanceDisks: cmdlib.LURecreateInstanceDisks,
-    opcodes.OpFailoverInstance: cmdlib.LUFailoverInstance,
-    opcodes.OpMigrateInstance: cmdlib.LUMigrateInstance,
-    opcodes.OpMoveInstance: cmdlib.LUMoveInstance,
-    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,
-    }
+  DISPATCH_TABLE = _ComputeDispatchTable()
 
   def __init__(self, context, ec_id):
     """Constructor for Processor
@@ -234,11 +201,11 @@ class Processor(object):
     self.context = context
     self._ec_id = ec_id
     self._cbs = None
-    self.rpc = rpc.RpcRunner(context.cfg)
+    self.rpc = context.rpc
     self.hmclass = HooksMaster
 
-  def _ReportLocks(self, level, names, shared, timeout, acquired, result):
-    """Reports lock operations.
+  def _AcquireLocks(self, level, names, shared, timeout, priority):
+    """Acquires locks via the Ganeti lock manager.
 
     @type level: int
     @param level: Lock level
@@ -248,69 +215,40 @@ class Processor(object):
     @param shared: Whether the locks should be acquired in shared mode
     @type timeout: None or float
     @param timeout: Timeout for acquiring the locks
-    @type acquired: bool
-    @param acquired: Whether the locks have already been acquired
-    @type result: None or set
-    @param result: Result from L{locking.GanetiLockManager.acquire}
+    @raise LockAcquireTimeout: In case locks couldn't be acquired in specified
+        amount of time
 
     """
-    parts = []
-
-    # Build message
-    if acquired:
-      if result is None:
-        parts.append("timeout")
-      else:
-        parts.append("acquired")
-    else:
-      parts.append("waiting")
-      if timeout is None:
-        parts.append("blocking")
-      else:
-        parts.append("timeout=%0.6fs" % timeout)
-
-    parts.append(locking.LEVEL_NAMES[level])
-
-    if names == locking.ALL_SET:
-      parts.append("ALL")
-    elif isinstance(names, basestring):
-      parts.append(names)
-    else:
-      parts.append(",".join(names))
-
-    if shared:
-      parts.append("shared")
-    else:
-      parts.append("exclusive")
+    if self._cbs:
+      self._cbs.CheckCancel()
 
-    msg = "/".join(parts)
+    acquired = self.context.glm.acquire(level, names, shared=shared,
+                                        timeout=timeout, priority=priority)
 
-    logging.debug("LU locks %s", msg)
+    if acquired is None:
+      raise LockAcquireTimeout()
 
-    if self._cbs:
-      self._cbs.ReportLocks(msg)
+    return acquired
 
-  def _AcquireLocks(self, level, names, shared, timeout):
-    """Acquires locks via the Ganeti lock manager.
+  def _ProcessResult(self, result):
+    """Examines opcode result.
 
-    @type level: int
-    @param level: Lock level
-    @type names: list or string
-    @param names: Lock names
-    @type shared: bool
-    @param shared: Whether the locks should be acquired in shared mode
-    @type timeout: None or float
-    @param timeout: Timeout for acquiring the locks
+    If necessary, additional processing on the result is done.
 
     """
-    self._ReportLocks(level, names, shared, timeout, False, None)
+    if isinstance(result, cmdlib.ResultWithJobs):
+      # Submit jobs
+      job_submission = self._cbs.SubmitManyJobs(result.jobs)
 
-    acquired = self.context.glm.acquire(level, names, shared=shared,
-                                        timeout=timeout)
+      # Build dictionary
+      result = result.other
 
-    self._ReportLocks(level, names, shared, timeout, True, acquired)
+      assert constants.JOB_IDS_KEY not in result, \
+        "Key '%s' found in additional return values" % constants.JOB_IDS_KEY
 
-    return acquired
+      result[constants.JOB_IDS_KEY] = job_submission
+
+    return result
 
   def _ExecLU(self, lu):
     """Logical Unit execution sequence.
@@ -318,10 +256,11 @@ class Processor(object):
     """
     write_count = self.context.cfg.write_count
     lu.CheckPrereq()
-    hm = HooksMaster(self.rpc.call_hooks_runner, lu)
+
+    hm = self.BuildHooksManager(lu)
     h_results = hm.RunPhase(constants.HOOKS_PHASE_PRE)
     lu.HooksCallBack(constants.HOOKS_PHASE_PRE, h_results,
-                     self._Feedback, None)
+                     self.Log, None)
 
     if getattr(lu.op, "dry_run", False):
       # in this mode, no post-hooks are run, and the config is not
@@ -332,10 +271,10 @@ class Processor(object):
       return lu.dry_run_result
 
     try:
-      result = lu.Exec(self._Feedback)
+      result = self._ProcessResult(lu.Exec(self.Log))
       h_results = hm.RunPhase(constants.HOOKS_PHASE_POST)
       result = lu.HooksCallBack(constants.HOOKS_PHASE_POST, h_results,
-                                self._Feedback, result)
+                                self.Log, result)
     finally:
       # FIXME: This needs locks if not lu_class.REQ_BGL
       if write_count != self.context.cfg.write_count:
@@ -343,7 +282,10 @@ class Processor(object):
 
     return result
 
-  def _LockAndExecLU(self, lu, level, calc_timeout):
+  def BuildHooksManager(self, lu):
+    return self.hmclass.BuildFromLu(lu.rpc.call_hooks_runner, lu)
+
+  def _LockAndExecLU(self, lu, level, calc_timeout, priority):
     """Execute a Logical Unit, with the needed locks.
 
     This is a recursive function that starts locking the given level, and
@@ -377,12 +319,8 @@ class Processor(object):
           # Acquiring locks
           needed_locks = lu.needed_locks[level]
 
-          acquired = self._AcquireLocks(level, needed_locks, share,
-                                        calc_timeout())
-
-          if acquired is None:
-            raise _LockAcquireTimeout()
-
+          self._AcquireLocks(level, needed_locks, share,
+                             calc_timeout(), priority)
         else:
           # Adding locks
           add_locks = lu.add_locks[level]
@@ -396,12 +334,8 @@ class Processor(object):
               " with another job, who added them first" % add_locks,
               errors.ECODE_FAULT)
 
-          acquired = add_locks
-
         try:
-          lu.acquired_locks[level] = acquired
-
-          result = self._LockAndExecLU(lu, level + 1, calc_timeout)
+          result = self._LockAndExecLU(lu, level + 1, calc_timeout, priority)
         finally:
           if level in lu.remove_locks:
             self.context.glm.remove(level, lu.remove_locks[level])
@@ -410,62 +344,72 @@ class Processor(object):
           self.context.glm.release(level)
 
     else:
-      result = self._LockAndExecLU(lu, level + 1, calc_timeout)
+      result = self._LockAndExecLU(lu, level + 1, calc_timeout, priority)
 
     return result
 
-  def ExecOpCode(self, op, cbs):
+  def ExecOpCode(self, op, cbs, timeout=None, priority=None):
     """Execute an opcode.
 
     @type op: an OpCode instance
     @param op: the opcode to be executed
     @type cbs: L{OpExecCbBase}
     @param cbs: Runtime callbacks
+    @type timeout: float or None
+    @param timeout: Maximum time to acquire all locks, None for no timeout
+    @type priority: number or None
+    @param priority: Priority for acquiring lock(s)
+    @raise LockAcquireTimeout: In case locks couldn't be acquired in specified
+        amount of time
 
     """
     if not isinstance(op, opcodes.OpCode):
       raise errors.ProgrammerError("Non-opcode instance passed"
-                                   " to ExecOpcode")
+                                   " to ExecOpcode (%s)" % type(op))
+
+    lu_class = self.DISPATCH_TABLE.get(op.__class__, None)
+    if lu_class is None:
+      raise errors.OpCodeUnknown("Unknown opcode")
+
+    if timeout is None:
+      calc_timeout = lambda: None
+    else:
+      calc_timeout = utils.RunningTimeout(timeout, False).Remaining
 
     self._cbs = cbs
     try:
-      lu_class = self.DISPATCH_TABLE.get(op.__class__, None)
-      if lu_class is None:
-        raise errors.OpCodeUnknown("Unknown opcode")
-
-      timeout_strategy = _LockAttemptTimeoutStrategy()
+      # 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._AcquireLocks(locking.LEVEL_CLUSTER, locking.BGL,
+                          not lu_class.REQ_BGL, calc_timeout(),
+                          priority)
+      try:
+        lu = lu_class(self, op, self.context, self.rpc)
+        lu.ExpandNames()
+        assert lu.needed_locks is not None, "needed_locks not set by LU"
 
-      while True:
         try:
-          acquire_timeout = timeout_strategy.CalcRemainingTimeout()
-
-          # 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.
-          if self._AcquireLocks(locking.LEVEL_CLUSTER, locking.BGL,
-                                not lu_class.REQ_BGL, acquire_timeout) is None:
-            raise _LockAcquireTimeout()
-
-          try:
-            lu = lu_class(self, op, self.context, self.rpc)
-            lu.ExpandNames()
-            assert lu.needed_locks is not None, "needed_locks not set by LU"
-
-            return self._LockAndExecLU(lu, locking.LEVEL_INSTANCE,
-                                       timeout_strategy.CalcRemainingTimeout)
-          finally:
-            self.context.glm.release(locking.LEVEL_CLUSTER)
-
-        except _LockAcquireTimeout:
-          # Timeout while waiting for lock, try again
-          pass
-
-        timeout_strategy = timeout_strategy.NextAttempt()
-
+          result = self._LockAndExecLU(lu, locking.LEVEL_INSTANCE, calc_timeout,
+                                       priority)
+        finally:
+          if self._ec_id:
+            self.context.cfg.DropECReservations(self._ec_id)
+      finally:
+        self.context.glm.release(locking.LEVEL_CLUSTER)
     finally:
       self._cbs = None
 
-  def _Feedback(self, *args):
+    resultcheck_fn = op.OP_RESULT
+    if not (resultcheck_fn is None or resultcheck_fn(result)):
+      logging.error("Expected opcode result matching %s, got %s",
+                    resultcheck_fn, result)
+      raise errors.OpResultError("Opcode result does not match %s" %
+                                 resultcheck_fn)
+
+    return result
+
+  def Log(self, *args):
     """Forward call to feedback callback function.
 
     """
@@ -477,7 +421,7 @@ class Processor(object):
 
     """
     logging.debug("Step %d/%d %s", current, total, message)
-    self._Feedback("STEP %d/%d %s" % (current, total, message))
+    self.Log("STEP %d/%d %s" % (current, total, message))
 
   def LogWarning(self, message, *args, **kwargs):
     """Log a warning to the logs and the user.
@@ -494,9 +438,9 @@ class Processor(object):
       message = message % tuple(args)
     if message:
       logging.warning(message)
-      self._Feedback(" - WARNING: %s" % message)
+      self.Log(" - WARNING: %s" % message)
     if "hint" in kwargs:
-      self._Feedback("      Hint: %s" % kwargs["hint"])
+      self.Log("      Hint: %s" % kwargs["hint"])
 
   def LogInfo(self, message, *args):
     """Log an informational message to the logs and the user.
@@ -505,80 +449,152 @@ class Processor(object):
     if args:
       message = message % tuple(args)
     logging.info(message)
-    self._Feedback(" - INFO: %s" % message)
+    self.Log(" - INFO: %s" % message)
 
   def GetECId(self):
+    """Returns the current execution context ID.
+
+    """
     if not self._ec_id:
-      errors.ProgrammerError("Tried to use execution context id when not set")
+      raise errors.ProgrammerError("Tried to use execution context id when"
+                                   " not set")
     return self._ec_id
 
 
 class HooksMaster(object):
-  """Hooks master.
-
-  This class distributes the run commands to the nodes based on the
-  specific LU class.
+  def __init__(self, opcode, hooks_path, nodes, hooks_execution_fn,
+    hooks_results_adapt_fn, build_env_fn, log_fn, htype=None, cluster_name=None,
+    master_name=None):
+    """Base class for hooks masters.
+
+    This class invokes the execution of hooks according to the behaviour
+    specified by its parameters.
+
+    @type opcode: string
+    @param opcode: opcode of the operation to which the hooks are tied
+    @type hooks_path: string
+    @param hooks_path: prefix of the hooks directories
+    @type nodes: 2-tuple of lists
+    @param nodes: 2-tuple of lists containing nodes on which pre-hooks must be
+      run and nodes on which post-hooks must be run
+    @type hooks_execution_fn: function that accepts the following parameters:
+      (node_list, hooks_path, phase, environment)
+    @param hooks_execution_fn: function that will execute the hooks; can be
+      None, indicating that no conversion is necessary.
+    @type hooks_results_adapt_fn: function
+    @param hooks_results_adapt_fn: function that will adapt the return value of
+      hooks_execution_fn to the format expected by RunPhase
+    @type build_env_fn: function that returns a dictionary having strings as
+      keys
+    @param build_env_fn: function that builds the environment for the hooks
+    @type log_fn: function that accepts a string
+    @param log_fn: logging function
+    @type htype: string or None
+    @param htype: None or one of L{constants.HTYPE_CLUSTER},
+     L{constants.HTYPE_NODE}, L{constants.HTYPE_INSTANCE}
+    @type cluster_name: string
+    @param cluster_name: name of the cluster
+    @type master_name: string
+    @param master_name: name of the master
 
-  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, lu):
-    self.callfn = callfn
-    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):
+    """
+    self.opcode = opcode
+    self.hooks_path = hooks_path
+    self.hooks_execution_fn = hooks_execution_fn
+    self.hooks_results_adapt_fn = hooks_results_adapt_fn
+    self.build_env_fn = build_env_fn
+    self.log_fn = log_fn
+    self.htype = htype
+    self.cluster_name = cluster_name
+    self.master_name = master_name
+
+    self.pre_env = self._BuildEnv(constants.HOOKS_PHASE_PRE)
+    (self.pre_nodes, self.post_nodes) = nodes
+
+  def _BuildEnv(self, phase):
     """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.
 
     """
+    if phase == constants.HOOKS_PHASE_PRE:
+      prefix = "GANETI_"
+    elif phase == constants.HOOKS_PHASE_POST:
+      prefix = "GANETI_POST_"
+    else:
+      raise AssertionError("Unknown phase '%s'" % phase)
+
+    env = {}
+
+    if self.hooks_path is not None:
+      phase_env = self.build_env_fn()
+      if phase_env:
+        assert not compat.any(key.upper().startswith(prefix)
+                              for key in phase_env)
+        env.update(("%s%s" % (prefix, key), value)
+                   for (key, value) in phase_env.items())
+
+    if phase == constants.HOOKS_PHASE_PRE:
+      assert compat.all((key.startswith("GANETI_") and
+                         not key.startswith("GANETI_POST_"))
+                        for key in env)
+
+    elif phase == constants.HOOKS_PHASE_POST:
+      assert compat.all(key.startswith("GANETI_POST_") for key in env)
+      assert isinstance(self.pre_env, dict)
+
+      # Merge with pre-phase environment
+      assert not compat.any(key.startswith("GANETI_POST_")
+                            for key in self.pre_env)
+      env.update(self.pre_env)
+    else:
+      raise AssertionError("Unknown phase '%s'" % phase)
+
+    return env
+
+  def _RunWrapper(self, node_list, hpath, phase, phase_env):
+    """Simple wrapper over self.callfn.
+
+    This method fixes the environment before executing the hooks.
+
+    """
     env = {
-      "PATH": "/sbin:/bin:/usr/sbin:/usr/bin",
+      "PATH": constants.HOOKS_PATH,
       "GANETI_HOOKS_VERSION": constants.HOOKS_VERSION,
-      "GANETI_OP_CODE": self.op.OP_ID,
-      "GANETI_OBJECT_TYPE": self.lu.HTYPE,
+      "GANETI_OP_CODE": self.opcode,
       "GANETI_DATA_DIR": constants.DATA_DIR,
+      "GANETI_HOOKS_PHASE": phase,
+      "GANETI_HOOKS_PATH": hpath,
       }
 
-    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)
+    if self.htype:
+      env["GANETI_OBJECT_TYPE"] = self.htype
 
-  def _RunWrapper(self, node_list, hpath, phase):
-    """Simple wrapper over self.callfn.
+    if self.cluster_name is not None:
+      env["GANETI_CLUSTER"] = self.cluster_name
 
-    This method fixes the environment before doing the rpc call.
+    if self.master_name is not None:
+      env["GANETI_MASTER"] = self.master_name
 
-    """
-    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()
+    if phase_env:
+      env = utils.algo.JoinDisjointDicts(env, phase_env)
 
+    # Convert everything to strings
     env = dict([(str(key), str(val)) for key, val in env.iteritems()])
 
-    return self.callfn(node_list, hpath, phase, env)
+    assert compat.all(key == "PATH" or key.startswith("GANETI_")
+                      for key in env)
+
+    return self.hooks_execution_fn(node_list, hpath, phase, env)
 
   def RunPhase(self, phase, nodes=None):
     """Run all the scripts for a phase.
 
     This is the main function of the HookMaster.
+    It executes self.hooks_execution_fn, and after running
+    self.hooks_results_adapt_fn on its results it expects them to be in the form
+    {node_name: (fail_msg, [(script, result, output), ...]}).
 
     @param phase: one of L{constants.HOOKS_PHASE_POST} or
         L{constants.HOOKS_PHASE_PRE}; it denotes the hooks phase
@@ -588,44 +604,58 @@ class HooksMaster(object):
     @raise errors.HooksAbort: on failure of one of the hooks
 
     """
-    if not self.node_list[phase] and not nodes:
+    if phase == constants.HOOKS_PHASE_PRE:
+      if nodes is None:
+        nodes = self.pre_nodes
+      env = self.pre_env
+    elif phase == constants.HOOKS_PHASE_POST:
+      if nodes is None:
+        nodes = self.post_nodes
+      env = self._BuildEnv(phase)
+    else:
+      raise AssertionError("Unknown phase '%s'" % phase)
+
+    if not nodes:
       # 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
-    if nodes is not None:
-      results = self._RunWrapper(nodes, hpath, phase)
-    else:
-      results = self._RunWrapper(self.node_list[phase], hpath, phase)
-    errs = []
+
+    results = self._RunWrapper(nodes, self.hooks_path, phase, env)
     if not results:
       msg = "Communication Failure"
       if phase == constants.HOOKS_PHASE_PRE:
         raise errors.HooksFailure(msg)
       else:
-        self.lu.LogWarning(msg)
+        self.log_fn(msg)
         return results
-    for node_name in results:
-      res = results[node_name]
-      if res.offline:
+
+    converted_res = results
+    if self.hooks_results_adapt_fn:
+      converted_res = self.hooks_results_adapt_fn(results)
+
+    errs = []
+    for node_name, (fail_msg, offline, hooks_results) in converted_res.items():
+      if offline:
         continue
-      msg = res.fail_msg
-      if msg:
-        self.lu.LogWarning("Communication failure to node %s: %s",
-                           node_name, msg)
+
+      if fail_msg:
+        self.log_fn("Communication failure to node %s: %s", node_name, fail_msg)
         continue
-      for script, hkr, output in res.payload:
+
+      for script, hkr, output in hooks_results:
         if hkr == constants.HKR_FAIL:
           if phase == constants.HOOKS_PHASE_PRE:
             errs.append((node_name, script, output))
           else:
             if not output:
               output = "(no output)"
-            self.lu.LogWarning("On %s script %s failed, output: %s" %
-                               (node_name, script, output))
+            self.log_fn("On %s script %s failed, output: %s" %
+                        (node_name, script, output))
+
     if errs and phase == constants.HOOKS_PHASE_PRE:
       raise errors.HooksAbort(errs)
+
     return results
 
   def RunConfigUpdate(self):
@@ -637,5 +667,21 @@ class HooksMaster(object):
     """
     phase = constants.HOOKS_PHASE_POST
     hpath = constants.HOOKS_NAME_CFGUPDATE
-    nodes = [self.lu.cfg.GetMasterNode()]
-    self._RunWrapper(nodes, hpath, phase)
+    nodes = [self.master_name]
+    self._RunWrapper(nodes, hpath, phase, self.pre_env)
+
+  @staticmethod
+  def BuildFromLu(hooks_execution_fn, lu):
+    if lu.HPATH is None:
+      nodes = (None, None)
+    else:
+      nodes = map(frozenset, lu.BuildHooksNodes())
+
+    master_name = cluster_name = None
+    if lu.cfg:
+      master_name = lu.cfg.GetMasterNode()
+      cluster_name = lu.cfg.GetClusterName()
+
+    return HooksMaster(lu.op.OP_ID, lu.HPATH, nodes, hooks_execution_fn,
+                       _RpcResultsToHooksResults, lu.BuildHooksEnv,
+                       lu.LogWarning, lu.HTYPE, cluster_name, master_name)