"""
import logging
+import random
+import time
from ganeti import opcodes
from ganeti import constants
from ganeti import rpc
from ganeti import cmdlib
from ganeti import locking
-from ganeti import utils
+
+
+class _LockAcquireTimeout(Exception):
+ """Internal exception to report timeouts on acquiring locks.
+
+ """
+
+
+def _CalculateLockAttemptTimeouts():
+ """Calculate timeouts for lock attempts.
+
+ """
+ running_sum = 0
+ result = [1.0]
+
+ # Wait for a total of at least 150s before doing a blocking acquire
+ while sum(result) < 150.0:
+ 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
+
+ result.append(timeout)
+
+ return result
+
+
+class _LockAttemptTimeoutStrategy(object):
+ """Class with lock acquire timeout strategy.
+
+ """
+ __slots__ = [
+ "_attempt",
+ "_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):
+ """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._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.
+
+ """
+ timeout = self._running_timeout.Remaining()
+
+ if timeout is not None:
+ # Add a small variation (-/+ 5%) to timeout. This helps in situations
+ # where two or more jobs are fighting for the same lock(s).
+ variation_range = timeout * 0.1
+ timeout += ((self._random_fn() * variation_range) -
+ (variation_range * 0.5))
+
+ return timeout
class OpExecCbBase:
"""
self.context = context
self._cbs = None
- self.exclusive_BGL = False
self.rpc = rpc.RpcRunner(context.cfg)
self.hmclass = HooksMaster
- def _ReportLocks(self, level, names, shared, acquired):
+ def _ReportLocks(self, level, names, shared, timeout, acquired, result):
"""Reports lock operations.
@type level: int
@type names: list or string
@param names: Lock names
@type shared: bool
- @param shared: Whether the lock should be acquired in shared mode
+ @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 lock has already been acquired
+ @param acquired: Whether the locks have already been acquired
+ @type result: None or set
+ @param result: Result from L{locking.GanetiLockManager.acquire}
"""
parts = []
# Build message
if acquired:
- parts.append("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 self._cbs:
self._cbs.ReportLocks(msg)
+ def _AcquireLocks(self, level, names, shared, timeout):
+ """Acquires locks via the Ganeti lock manager.
+
+ @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
+
+ """
+ self._ReportLocks(level, names, shared, timeout, False, None)
+
+ acquired = self.context.glm.acquire(level, names, shared=shared,
+ timeout=timeout)
+
+ self._ReportLocks(level, names, shared, timeout, True, acquired)
+
+ return acquired
+
def _ExecLU(self, lu):
"""Logical Unit execution sequence.
return result
- def _LockAndExecLU(self, lu, level):
+ def _LockAndExecLU(self, lu, level, calc_timeout):
"""Execute a Logical Unit, with the needed locks.
This is a recursive function that starts locking the given level, and
self._cbs.NotifyStart()
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")
+ 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]
-
- self._ReportLocks(level, needed_locks, share, False)
- lu.acquired_locks[level] = self.context.glm.acquire(level,
- needed_locks,
- shared=share)
- self._ReportLocks(level, needed_locks, share, True)
-
- 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(
- "Couldn't add locks (%s), probably because of a race condition"
- " with another job, who added them first" % add_locks)
+
try:
+ assert adding_locks ^ acquiring_locks, \
+ "Locks must be either added or acquired"
+
+ if acquiring_locks:
+ # Acquiring locks
+ needed_locks = lu.needed_locks[level]
+
+ acquired = self._AcquireLocks(level, needed_locks, share,
+ calc_timeout())
+
+ if acquired is None:
+ raise _LockAcquireTimeout()
+
+ 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(
+ "Couldn't add locks (%s), probably because of a race condition"
+ " with another job, who added them first" % add_locks,
+ errors.ECODE_FAULT)
+
+ acquired = add_locks
+
try:
- if adding_locks:
- lu.acquired_locks[level] = add_locks
- result = self._LockAndExecLU(lu, level + 1)
+ lu.acquired_locks[level] = acquired
+
+ result = self._LockAndExecLU(lu, level + 1, calc_timeout)
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)
+ result = self._LockAndExecLU(lu, level + 1, calc_timeout)
return result
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._ReportLocks(locking.LEVEL_CLUSTER, [locking.BGL],
- not lu_class.REQ_BGL, False)
- try:
- self.context.glm.acquire(locking.LEVEL_CLUSTER, [locking.BGL],
- shared=not lu_class.REQ_BGL)
- finally:
- self._ReportLocks(locking.LEVEL_CLUSTER, [locking.BGL],
- not lu_class.REQ_BGL, True)
- 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
+ timeout_strategy = _LockAttemptTimeoutStrategy()
+
+ 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()
+
finally:
self._cbs = None
- return result
-
def _Feedback(self, *args):
"""Forward call to feedback callback function.
projects / ganeti-local / blobdiff