This program and set of classes implement a watchdog to restart
virtual machines in a Ganeti cluster that have crashed or been killed
by a node reboot. Run from cron or similar.
-"""
-
-LOGFILE = '/var/log/ganeti/watcher.log'
-MAXTRIES = 5
-BAD_STATES = ['stopped']
-HELPLESS_STATES = ['(node down)']
-NOTICE = 'NOTICE'
-ERROR = 'ERROR'
+"""
import os
import sys
+import re
import time
import fcntl
import errno
+import simplejson
from optparse import OptionParser
-
from ganeti import utils
from ganeti import constants
+from ganeti import ssconf
+from ganeti import errors
+
+
+MAXTRIES = 5
+BAD_STATES = ['stopped']
+HELPLESS_STATES = ['(node down)']
+NOTICE = 'NOTICE'
+ERROR = 'ERROR'
+KEY_RESTART_COUNT = "restart_count"
+KEY_RESTART_WHEN = "restart_when"
+KEY_BOOT_ID = "bootid"
class Error(Exception):
"""Generic custom error class."""
- pass
+
+
+class NotMasterError(Error):
+ """Exception raised when this host is not the master."""
def Indent(s, prefix='| '):
Args:
s: The string to indent
prefix: The string to prepend each line.
+
"""
return "%s%s\n" % (prefix, ('\n' + prefix).join(s.splitlines()))
cmd: the command to run.
Raises CommandError with verbose commentary on error.
+
"""
res = utils.RunCmd(cmd)
return res
-class RestarterState(object):
+class WatcherState(object):
"""Interface to a state file recording restart attempts.
- Methods:
- Open(): open, lock, read and parse the file.
- Raises StandardError on lock contention.
-
- NumberOfAttempts(name): returns the number of times in succession
- a restart has been attempted of the named instance.
-
- RecordAttempt(name, when): records one restart attempt of name at
- time in when.
-
- Remove(name): remove record given by name, if exists.
-
- Save(name): saves all records to file, releases lock and closes file.
"""
def __init__(self):
+ """Open, lock, read and parse the file.
+
+ Raises StandardError on lock contention.
+
+ """
# The two-step dance below is necessary to allow both opening existing
# file read/write and creating if not existing. Vanilla open will truncate
# an existing file -or- allow creating if not existing.
fcntl.flock(f.fileno(), fcntl.LOCK_EX|fcntl.LOCK_NB)
except IOError, x:
if x.errno == errno.EAGAIN:
- raise StandardError('State file already locked')
+ raise StandardError("State file already locked")
raise
self.statefile = f
- self.inst_map = {}
- for line in f:
- name, when, count = line.rstrip().split(':')
+ try:
+ self.data = simplejson.load(self.statefile)
+ except Exception, msg:
+ # Ignore errors while loading the file and treat it as empty
+ self.data = {}
+ sys.stderr.write("Empty or invalid state file."
+ " Using defaults. Error message: %s\n" % msg)
+
+ if "instance" not in self.data:
+ self.data["instance"] = {}
+ if "node" not in self.data:
+ self.data["node"] = {}
+
+ def __del__(self):
+ """Called on destruction.
+
+ """
+ if self.statefile:
+ self._Close()
+
+ def _Close(self):
+ """Unlock configuration file and close it.
+
+ """
+ assert self.statefile
+
+ fcntl.flock(self.statefile.fileno(), fcntl.LOCK_UN)
+
+ self.statefile.close()
+ self.statefile = None
- when = int(when)
- count = int(count)
+ def GetNodeBootID(self, name):
+ """Returns the last boot ID of a node or None.
+
+ """
+ ndata = self.data["node"]
- self.inst_map[name] = (when, count)
+ if name in ndata and KEY_BOOT_ID in ndata[name]:
+ return ndata[name][KEY_BOOT_ID]
+ return None
+
+ def SetNodeBootID(self, name, bootid):
+ """Sets the boot ID of a node.
+
+ """
+ assert bootid
- def NumberOfAttempts(self, instance):
+ ndata = self.data["node"]
+
+ if name not in ndata:
+ ndata[name] = {}
+
+ ndata[name][KEY_BOOT_ID] = bootid
+
+ def NumberOfRestartAttempts(self, instance):
"""Returns number of previous restart attempts.
Args:
instance - the instance to look up.
+
"""
- assert self.statefile
+ idata = self.data["instance"]
- if instance.name in self.inst_map:
- return self.inst_map[instance.name][1]
+ if instance.name in idata:
+ return idata[instance.name][KEY_RESTART_COUNT]
return 0
- def RecordAttempt(self, instance):
+ def RecordRestartAttempt(self, instance):
"""Record a restart attempt.
Args:
instance - the instance being restarted
+
"""
- assert self.statefile
+ idata = self.data["instance"]
- when = time.time()
+ if instance.name not in idata:
+ inst = idata[instance.name] = {}
+ else:
+ inst = idata[instance.name]
- self.inst_map[instance.name] = (when, 1 + self.NumberOfAttempts(instance))
+ inst[KEY_RESTART_WHEN] = time.time()
+ inst[KEY_RESTART_COUNT] = inst.get(KEY_RESTART_COUNT, 0) + 1
- def Remove(self, instance):
- """Update state to reflect that a machine is running, i.e. remove record
+ def RemoveInstance(self, instance):
+ """Update state to reflect that a machine is running, i.e. remove record.
Args:
instance - the instance to remove from books
- This method removes the record for a named instance
+ This method removes the record for a named instance.
+
"""
- assert self.statefile
+ idata = self.data["instance"]
- if instance.name in self.inst_map:
- del self.inst_map[instance.name]
+ if instance.name in idata:
+ del idata[instance.name]
def Save(self):
- """Save records to file, then unlock and close file.
+ """Save state to file, then unlock and close it.
+
"""
assert self.statefile
self.statefile.seek(0)
self.statefile.truncate()
- for name in self.inst_map:
- print >> self.statefile, "%s:%d:%d" % ((name,) + self.inst_map[name])
+ simplejson.dump(self.data, self.statefile)
- fcntl.flock(self.statefile.fileno(), fcntl.LOCK_UN)
-
- self.statefile.close()
- self.statefile = None
+ self._Close()
class Instance(object):
Methods:
Restart(): issue a command to restart the represented machine.
+
"""
- def __init__(self, name, state):
+ def __init__(self, name, state, autostart):
self.name = name
self.state = state
+ self.autostart = autostart
def Restart(self):
+ """Encapsulates the start of an instance.
+
+ """
DoCmd(['gnt-instance', 'startup', '--lock-retries=15', self.name])
+ def ActivateDisks(self):
+ """Encapsulates the activation of all disks of an instance.
+
+ """
+ DoCmd(['gnt-instance', 'activate-disks', '--lock-retries=15', self.name])
+
+
+def _RunListCmd(cmd):
+ """Runs a command and parses its output into lists.
-class InstanceList(object):
- """The set of Virtual Machine instances on a cluster.
"""
- cmd = ['gnt-instance', 'list', '--lock-retries=15',
- '-o', 'name,admin_state,oper_state', '--no-headers', '--separator=:']
+ for line in DoCmd(cmd).stdout.splitlines():
+ yield line.split(':')
- def __init__(self):
- res = DoCmd(self.cmd)
- lines = res.stdout.splitlines()
+def GetInstanceList(with_secondaries=None):
+ """Get a list of instances on this cluster.
+
+ """
+ cmd = ['gnt-instance', 'list', '--lock-retries=15', '--no-headers',
+ '--separator=:']
+
+ fields = 'name,oper_state,admin_state'
+
+ if with_secondaries is not None:
+ fields += ',snodes'
- self.instances = []
- for line in lines:
- fields = [fld.strip() for fld in line.split(':')]
+ cmd.append('-o')
+ cmd.append(fields)
- if len(fields) != 3:
+ instances = []
+ for fields in _RunListCmd(cmd):
+ if with_secondaries is not None:
+ (name, status, autostart, snodes) = fields
+
+ if snodes == "-":
continue
- if fields[1] == "no": #no autostart, we don't care about this instance
+
+ for node in with_secondaries:
+ if node in snodes.split(','):
+ break
+ else:
continue
- name, status = fields[0], fields[2]
- self.instances.append(Instance(name, status))
+ else:
+ (name, status, autostart) = fields
+
+ instances.append(Instance(name, status, autostart != "no"))
+
+ return instances
+
- def __iter__(self):
- return self.instances.__iter__()
+def GetNodeBootIDs():
+ """Get a dict mapping nodes to boot IDs.
+
+ """
+ cmd = ['gnt-node', 'list', '--lock-retries=15', '--no-headers',
+ '--separator=:', '-o', 'name,bootid']
+
+ ids = {}
+ for fields in _RunListCmd(cmd):
+ (name, bootid) = fields
+ ids[name] = bootid
+
+ return ids
class Message(object):
"""Encapsulation of a notice or error message.
+
"""
def __init__(self, level, msg):
self.level = level
return self.level + ' ' + time.ctime(self.when) + '\n' + Indent(self.msg)
-class Restarter(object):
+class Watcher(object):
"""Encapsulate the logic for restarting erronously halted virtual machines.
The calling program should periodically instantiate me and call Run().
This will traverse the list of instances, and make up to MAXTRIES attempts
to restart machines that are down.
+
"""
def __init__(self):
- self.instances = InstanceList()
+ sstore = ssconf.SimpleStore()
+ master = sstore.GetMasterNode()
+ if master != utils.HostInfo().name:
+ raise NotMasterError("This is not the master node")
+ self.instances = GetInstanceList()
+ self.bootids = GetNodeBootIDs()
self.messages = []
def Run(self):
- """Make a pass over the list of instances, restarting downed ones.
+ notepad = WatcherState()
+ self.CheckInstances(notepad)
+ self.CheckDisks(notepad)
+ self.VerifyDisks()
+ notepad.Save()
+
+ def CheckDisks(self, notepad):
+ """Check all nodes for restarted ones.
+
"""
- notepad = RestarterState()
+ check_nodes = []
+ for name, id in self.bootids.iteritems():
+ old = notepad.GetNodeBootID(name)
+ if old != id:
+ # Node's boot ID has changed, proably through a reboot.
+ check_nodes.append(name)
+
+ if check_nodes:
+ # Activate disks for all instances with any of the checked nodes as a
+ # secondary node.
+ for instance in GetInstanceList(with_secondaries=check_nodes):
+ try:
+ self.messages.append(Message(NOTICE, ("Activating disks for %s." %
+ instance.name)))
+ instance.ActivateDisks()
+ except Error, x:
+ self.messages.append(Message(ERROR, str(x)))
+ # Keep changed boot IDs
+ for name in check_nodes:
+ notepad.SetNodeBootID(name, self.bootids[name])
+
+ def CheckInstances(self, notepad):
+ """Make a pass over the list of instances, restarting downed ones.
+
+ """
for instance in self.instances:
+ # Don't care about manually stopped instances
+ if not instance.autostart:
+ continue
+
if instance.state in BAD_STATES:
- n = notepad.NumberOfAttempts(instance)
+ n = notepad.NumberOfRestartAttempts(instance)
if n > MAXTRIES:
# stay quiet.
elif n < MAXTRIES:
last = " (Attempt #%d)" % (n + 1)
else:
- notepad.RecordAttempt(instance)
+ notepad.RecordRestartAttempt(instance)
self.messages.append(Message(ERROR, "Could not restart %s for %d"
" times, giving up..." %
(instance.name, MAXTRIES)))
continue
try:
- self.messages.append(Message(NOTICE,
- "Restarting %s%s." %
- (instance.name, last)))
+ self.messages.append(Message(NOTICE, ("Restarting %s%s." %
+ (instance.name, last))))
instance.Restart()
except Error, x:
self.messages.append(Message(ERROR, str(x)))
- notepad.RecordAttempt(instance)
+ notepad.RecordRestartAttempt(instance)
elif instance.state in HELPLESS_STATES:
- if notepad.NumberOfAttempts(instance):
- notepad.Remove(instance)
+ if notepad.NumberOfRestartAttempts(instance):
+ notepad.RemoveInstance(instance)
else:
- if notepad.NumberOfAttempts(instance):
- notepad.Remove(instance)
- msg = Message(NOTICE,
- "Restart of %s succeeded." % instance.name)
+ if notepad.NumberOfRestartAttempts(instance):
+ notepad.RemoveInstance(instance)
+ msg = Message(NOTICE, "Restart of %s succeeded." % instance.name)
self.messages.append(msg)
- notepad.Save()
+ def VerifyDisks(self):
+ """Run gnt-cluster verify-disks.
- def WriteReport(self, logfile):
"""
- Log all messages to file.
+ result = DoCmd(['gnt-cluster', 'verify-disks', '--lock-retries=15'])
+ if result.output:
+ self.messages.append(Message(NOTICE, result.output))
+
+ def WriteReport(self, logfile):
+ """Log all messages to file.
Args:
logfile: file object open for writing (the log file)
+
"""
for msg in self.messages:
print >> logfile, str(msg)
options, args = ParseOptions()
if not options.debug:
- sys.stderr = sys.stdout = open(LOGFILE, 'a')
+ sys.stderr = sys.stdout = open(constants.LOG_WATCHER, 'a')
try:
- restarter = Restarter()
- restarter.Run()
- restarter.WriteReport(sys.stdout)
+ try:
+ watcher = Watcher()
+ except errors.ConfigurationError:
+ # Just exit if there's no configuration
+ sys.exit(constants.EXIT_SUCCESS)
+ watcher.Run()
+ watcher.WriteReport(sys.stdout)
+ except NotMasterError:
+ if options.debug:
+ sys.stderr.write("Not master, exiting.\n")
+ sys.exit(constants.EXIT_NOTMASTER)
+ except errors.ResolverError, err:
+ sys.stderr.write("Cannot resolve hostname '%s', exiting.\n" % err.args[0])
+ sys.exit(constants.EXIT_NODESETUP_ERROR)
except Error, err:
print err
+
if __name__ == '__main__':
main()
projects / ganeti-local / blobdiff