4 # Copyright (C) 2009, Google Inc.
6 # This program is free software; you can redistribute it and/or modify
7 # it under the terms of the GNU General Public License as published by
8 # the Free Software Foundation; either version 2 of the License, or
9 # (at your option) any later version.
11 # This program is distributed in the hope that it will be useful, but
12 # WITHOUT ANY WARRANTY; without even the implied warranty of
13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 # General Public License for more details.
16 # You should have received a copy of the GNU General Public License
17 # along with this program; if not, write to the Free Software
18 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
22 """Ganeti configuration daemon
24 Ganeti-confd is a daemon to query master candidates for configuration values.
25 It uses UDP+HMAC for authentication with a global cluster key.
29 # pylint: disable-msg=C0103
30 # C0103: Invalid name ganeti-confd
38 # pylint: disable-msg=E0611
39 from pyinotify import pyinotify
43 from optparse import OptionParser
45 from ganeti import asyncnotifier
46 from ganeti import confd
47 from ganeti.confd import server as confd_server
48 from ganeti import constants
49 from ganeti import errors
50 from ganeti import daemon
53 class ConfdAsyncUDPServer(daemon.AsyncUDPSocket):
54 """The confd udp server, suitable for use with asyncore.
57 def __init__(self, bind_address, port, processor):
58 """Constructor for ConfdAsyncUDPServer
60 @type bind_address: string
61 @param bind_address: socket bind address ('' for all)
64 @type processor: L{confd.server.ConfdProcessor}
65 @param processor: ConfdProcessor to use to handle queries
68 daemon.AsyncUDPSocket.__init__(self)
69 self.bind_address = bind_address
71 self.processor = processor
72 self.bind((bind_address, port))
73 logging.debug("listening on ('%s':%d)", bind_address, port)
75 # this method is overriding a daemon.AsyncUDPSocket method
76 def handle_datagram(self, payload_in, ip, port):
78 query = confd.UnpackMagic(payload_in)
79 except errors.ConfdMagicError, err:
83 answer = self.processor.ExecQuery(query, ip, port)
84 if answer is not None:
86 self.enqueue_send(ip, port, confd.PackMagic(answer))
87 except errors.UdpDataSizeError:
88 logging.error("Reply too big to fit in an udp packet.")
91 class ConfdInotifyEventHandler(pyinotify.ProcessEvent):
93 def __init__(self, watch_manager, callback,
94 filename=constants.CLUSTER_CONF_FILE):
95 """Constructor for ConfdInotifyEventHandler
97 @type watch_manager: L{pyinotify.WatchManager}
98 @param watch_manager: ganeti-confd inotify watch manager
99 @type callback: function accepting a boolean
100 @param callback: function to call when an inotify event happens
101 @type filename: string
102 @param filename: config file to watch
105 # no need to call the parent's constructor
106 self.watch_manager = watch_manager
107 self.callback = callback
108 # pylint: disable-msg=E1103
109 # pylint for some reason doesn't see the below constants
110 self.mask = pyinotify.EventsCodes.IN_IGNORED | \
111 pyinotify.EventsCodes.IN_MODIFY
113 self.watch_handle = None
116 """Watch the given file
119 if self.watch_handle is None:
120 result = self.watch_manager.add_watch(self.file, self.mask)
121 if not self.file in result or result[self.file] <= 0:
122 raise errors.InotifyError("Could not add inotify watcher")
124 self.watch_handle = result[self.file]
127 """Stop watching the given file
130 if self.watch_handle is not None:
131 result = self.watch_manager.rm_watch(self.watch_handle)
132 if result[self.watch_handle]:
133 self.watch_handle = None
135 def process_IN_IGNORED(self, event):
136 # Due to the fact that we monitor just for the cluster config file (rather
137 # than for the whole data dir) when the file is replaced with another one
138 # (which is what happens normally in ganeti) we're going to receive an
139 # IN_IGNORED event from inotify, because of the file removal (which is
140 # contextual with the replacement). In such a case we need to create
141 # another watcher for the "new" file.
142 logging.debug("Received 'ignored' inotify event for %s", event.path)
143 self.watch_handle = None
146 # Since the kernel believes the file we were interested in is gone, it's
147 # not going to notify us of any other events, until we set up, here, the
148 # new watch. This is not a race condition, though, since we're anyway
149 # going to realod the file after setting up the new watch.
151 except errors.ConfdFatalError, err:
152 logging.critical("Critical error, shutting down: %s", err)
153 sys.exit(constants.EXIT_FAILURE)
155 # we need to catch any exception here, log it, but proceed, because even
156 # if we failed handling a single request, we still want the confd to
158 logging.error("Unexpected exception", exc_info=True)
160 def process_IN_MODIFY(self, event):
161 # This gets called when the config file is modified. Note that this doesn't
162 # usually happen in Ganeti, as the config file is normally replaced by a
163 # new one, at filesystem level, rather than actually modified (see
165 logging.debug("Received 'modify' inotify event for %s", event.path)
169 except errors.ConfdFatalError, err:
170 logging.critical("Critical error, shutting down: %s", err)
171 sys.exit(constants.EXIT_FAILURE)
173 # we need to catch any exception here, log it, but proceed, because even
174 # if we failed handling a single request, we still want the confd to
176 logging.error("Unexpected exception", exc_info=True)
178 def process_default(self, event):
179 logging.error("Received unhandled inotify event: %s", event)
182 class ConfdConfigurationReloader(object):
183 """Logic to control when to reload the ganeti configuration
185 This class is able to alter between inotify and polling, to rate-limit the
186 number of reloads. When using inotify it also supports a fallback timed
187 check, to verify that the reload hasn't failed.
190 def __init__(self, processor, mainloop):
191 """Constructor for ConfdConfigurationReloader
193 @type processor: L{confd.server.ConfdProcessor}
194 @param processor: ganeti-confd ConfdProcessor
195 @type mainloop: L{daemon.Mainloop}
196 @param mainloop: ganeti-confd mainloop
199 self.processor = processor
200 self.mainloop = mainloop
203 self.last_notification = 0
205 # Asyncronous inotify handler for config changes
206 self.wm = pyinotify.WatchManager()
207 self.inotify_handler = ConfdInotifyEventHandler(self.wm, self.OnInotify)
208 self.notifier = asyncnotifier.AsyncNotifier(self.wm, self.inotify_handler)
210 self.timer_handle = None
213 def OnInotify(self, notifier_enabled):
214 """Receive an inotify notification.
216 @type notifier_enabled: boolean
217 @param notifier_enabled: whether the notifier is still enabled
220 current_time = time.time()
221 time_delta = current_time - self.last_notification
222 self.last_notification = current_time
224 if time_delta < constants.CONFD_CONFIG_RELOAD_RATELIMIT:
225 logging.debug("Moving from inotify mode to polling mode")
228 self.inotify_handler.disable()
230 if not self.polling and not notifier_enabled:
232 self.inotify_handler.enable()
233 except errors.InotifyError:
237 reloaded = self.processor.reader.Reload()
239 logging.info("Reloaded ganeti config")
241 logging.debug("Skipped double config reload")
242 except errors.ConfigurationError:
244 self.inotify_handler.disable()
247 # Reset the timer. If we're polling it will go to the polling rate, if
248 # we're not it will delay it again to its base safe timeout.
251 def _DisableTimer(self):
252 if self.timer_handle is not None:
253 self.mainloop.scheduler.cancel(self.timer_handle)
254 self.timer_handle = None
256 def _EnableTimer(self):
258 timeout = constants.CONFD_CONFIG_RELOAD_RATELIMIT
260 timeout = constants.CONFD_CONFIG_RELOAD_TIMEOUT
262 if self.timer_handle is None:
263 self.timer_handle = self.mainloop.scheduler.enter(
264 timeout, 1, self.OnTimer, [])
266 def _ResetTimer(self):
271 """Function called when the timer fires
274 self.timer_handle = None
278 if self.processor.reader is None:
283 reloaded = self.processor.reader.Reload()
284 except errors.ConfigurationError:
285 self.DisableConfd(silent=was_disabled)
288 if self.polling and reloaded:
289 logging.info("Reloaded ganeti config")
291 # We have reloaded the config files, but received no inotify event. If
292 # an event is pending though, we just happen to have timed out before
293 # receiving it, so this is not a problem, and we shouldn't alert
294 if not self.notifier.check_events() and not was_disabled:
295 logging.warning("Config file reload at timeout (inotify failure)")
297 # We're polling, but we haven't reloaded the config:
298 # Going back to inotify mode
299 logging.debug("Moving from polling mode to inotify mode")
302 self.inotify_handler.enable()
303 except errors.InotifyError:
306 logging.debug("Performed configuration check")
310 def DisableConfd(self, silent=False):
311 """Puts confd in non-serving mode
315 logging.warning("Confd is being disabled")
316 self.processor.Disable()
320 def EnableConfd(self):
321 self.processor.Enable()
322 logging.warning("Confd is being enabled")
327 def CheckConfd(_, args):
328 """Initial checks whether to run exit with a failure.
331 if args: # confd doesn't take any arguments
332 print >> sys.stderr, ("Usage: %s [-f] [-d] [-b ADDRESS]" % sys.argv[0])
333 sys.exit(constants.EXIT_FAILURE)
335 # TODO: collapse HMAC daemons handling in daemons GenericMain, when we'll
336 # have more than one.
337 if not os.path.isfile(constants.HMAC_CLUSTER_KEY):
338 print >> sys.stderr, "Need HMAC key %s to run" % constants.HMAC_CLUSTER_KEY
339 sys.exit(constants.EXIT_FAILURE)
342 def ExecConfd(options, _):
343 """Main confd function, executed with PID file held
346 # TODO: clarify how the server and reloader variables work (they are
348 # pylint: disable-msg=W0612
349 mainloop = daemon.Mainloop()
351 # Asyncronous confd UDP server
352 processor = confd_server.ConfdProcessor()
355 except errors.ConfigurationError:
356 # If enabling the processor has failed, we can still go on, but confd will
358 logging.warning("Confd is starting in disabled mode")
360 server = ConfdAsyncUDPServer(options.bind_address, options.port, processor)
362 # Configuration reloader
363 reloader = ConfdConfigurationReloader(processor, mainloop)
369 """Main function for the confd daemon.
372 parser = OptionParser(description="Ganeti configuration daemon",
373 usage="%prog [-f] [-d] [-b ADDRESS]",
374 version="%%prog (ganeti) %s" %
375 constants.RELEASE_VERSION)
377 dirs = [(val, constants.RUN_DIRS_MODE) for val in constants.SUB_RUN_DIRS]
378 dirs.append((constants.LOCK_DIR, 1777))
379 daemon.GenericMain(constants.CONFD, parser, dirs, CheckConfd, ExecConfd)
382 if __name__ == "__main__":