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.
35 from optparse import OptionParser
37 from ganeti import asyncnotifier
38 from ganeti import confd
39 from ganeti.confd import server as confd_server
40 from ganeti import constants
41 from ganeti import errors
42 from ganeti import daemon
43 from ganeti import utils
44 from ganeti import ssconf
47 class ConfdAsyncUDPServer(daemon.AsyncUDPSocket):
48 """The confd udp server, suitable for use with asyncore.
51 def __init__(self, bind_address, port, processor):
52 """Constructor for ConfdAsyncUDPServer
54 @type bind_address: string
55 @param bind_address: socket bind address ('' for all)
58 @type processor: L{confd.server.ConfdProcessor}
59 @param processor: ConfdProcessor to use to handle queries
62 daemon.AsyncUDPSocket.__init__(self)
63 self.bind_address = bind_address
65 self.processor = processor
66 self.bind((bind_address, port))
67 logging.debug("listening on ('%s':%d)" % (bind_address, port))
69 # this method is overriding a daemon.AsyncUDPSocket method
70 def handle_datagram(self, payload_in, ip, port):
72 query = confd.UnpackMagic(payload_in)
73 except errors.ConfdMagicError, err:
77 answer = self.processor.ExecQuery(query, ip, port)
78 if answer is not None:
80 self.enqueue_send(ip, port, confd.PackMagic(answer))
81 except errors.UdpDataSizeError:
82 logging.error("Reply too big to fit in an udp packet.")
85 class ConfdInotifyEventHandler(pyinotify.ProcessEvent):
87 def __init__(self, watch_manager, callback,
88 file=constants.CLUSTER_CONF_FILE):
89 """Constructor for ConfdInotifyEventHandler
91 @type watch_manager: L{pyinotify.WatchManager}
92 @param watch_manager: ganeti-confd inotify watch manager
93 @type callback: function accepting a boolean
94 @param callback: function to call when an inotify event happens
96 @param file: config file to watch
99 # no need to call the parent's constructor
100 self.watch_manager = watch_manager
101 self.callback = callback
102 self.mask = pyinotify.EventsCodes.IN_IGNORED | \
103 pyinotify.EventsCodes.IN_MODIFY
105 self.watch_handle = None
108 """Watch the given file
111 if self.watch_handle is None:
112 result = self.watch_manager.add_watch(self.file, self.mask)
113 if not self.file in result or result[self.file] <= 0:
114 raise errors.InotifyError("Could not add inotify watcher")
116 self.watch_handle = result[self.file]
119 """Stop watching the given file
122 if self.watch_handle is not None:
123 result = self.watch_manager.rm_watch(self.watch_handle)
124 if result[self.watch_handle]:
125 self.watch_handle = None
127 def process_IN_IGNORED(self, event):
128 # Due to the fact that we monitor just for the cluster config file (rather
129 # than for the whole data dir) when the file is replaced with another one
130 # (which is what happens normally in ganeti) we're going to receive an
131 # IN_IGNORED event from inotify, because of the file removal (which is
132 # contextual with the replacement). In such a case we need to create
133 # another watcher for the "new" file.
134 logging.debug("Received 'ignored' inotify event for %s" % event.path)
135 self.watch_handle = None
138 # Since the kernel believes the file we were interested in is gone, it's
139 # not going to notify us of any other events, until we set up, here, the
140 # new watch. This is not a race condition, though, since we're anyway
141 # going to realod the file after setting up the new watch.
143 except errors.ConfdFatalError, err:
144 logging.critical("Critical error, shutting down: %s" % err)
145 sys.exit(constants.EXIT_FAILURE)
147 # we need to catch any exception here, log it, but proceed, because even
148 # if we failed handling a single request, we still want the confd to
150 logging.error("Unexpected exception", exc_info=True)
152 def process_IN_MODIFY(self, event):
153 # This gets called when the config file is modified. Note that this doesn't
154 # usually happen in Ganeti, as the config file is normally replaced by a
155 # new one, at filesystem level, rather than actually modified (see
157 logging.debug("Received 'modify' inotify event for %s" % event.path)
161 except errors.ConfdFatalError, err:
162 logging.critical("Critical error, shutting down: %s" % err)
163 sys.exit(constants.EXIT_FAILURE)
165 # we need to catch any exception here, log it, but proceed, because even
166 # if we failed handling a single request, we still want the confd to
168 logging.error("Unexpected exception", exc_info=True)
170 def process_default(self, event):
171 logging.error("Received unhandled inotify event: %s" % event)
174 class ConfdConfigurationReloader(object):
175 """Logic to control when to reload the ganeti configuration
177 This class is able to alter between inotify and polling, to rate-limit the
178 number of reloads. When using inotify it also supports a fallback timed
179 check, to verify that the reload hasn't failed.
182 def __init__(self, processor, mainloop):
183 """Constructor for ConfdConfigurationReloader
185 @type processor: L{confd.server.ConfdProcessor}
186 @param processor: ganeti-confd ConfdProcessor
187 @type mainloop: L{daemon.Mainloop}
188 @param mainloop: ganeti-confd mainloop
191 self.processor = processor
192 self.mainloop = mainloop
195 self.last_notification = 0
197 # Asyncronous inotify handler for config changes
198 self.wm = pyinotify.WatchManager()
199 self.inotify_handler = ConfdInotifyEventHandler(self.wm, self.OnInotify)
200 self.notifier = asyncnotifier.AsyncNotifier(self.wm, self.inotify_handler)
202 self.timer_handle = None
205 def OnInotify(self, notifier_enabled):
206 """Receive an inotify notification.
208 @type notifier_enabled: boolean
209 @param notifier_enabled: whether the notifier is still enabled
212 current_time = time.time()
213 time_delta = current_time - self.last_notification
214 self.last_notification = current_time
216 if time_delta < constants.CONFD_CONFIG_RELOAD_RATELIMIT:
217 logging.debug("Moving from inotify mode to polling mode")
220 self.inotify_handler.disable()
222 if not self.polling and not notifier_enabled:
224 self.inotify_handler.enable()
225 except errors.InotifyError:
229 reloaded = self.processor.reader.Reload()
231 logging.info("Reloaded ganeti config")
233 logging.debug("Skipped double config reload")
234 except errors.ConfigurationError:
236 self.inotify_handler.disable()
239 # Reset the timer. If we're polling it will go to the polling rate, if
240 # we're not it will delay it again to its base safe timeout.
243 def _DisableTimer(self):
244 if self.timer_handle is not None:
245 self.mainloop.scheduler.cancel(self.timer_handle)
246 self.timer_handle = None
248 def _EnableTimer(self):
250 timeout = constants.CONFD_CONFIG_RELOAD_RATELIMIT
252 timeout = constants.CONFD_CONFIG_RELOAD_TIMEOUT
254 if self.timer_handle is None:
255 self.timer_handle = self.mainloop.scheduler.enter(
256 timeout, 1, self.OnTimer, [])
258 def _ResetTimer(self):
263 """Function called when the timer fires
266 self.timer_handle = None
270 if self.processor.reader is None:
275 reloaded = self.processor.reader.Reload()
276 except errors.ConfigurationError:
277 self.DisableConfd(silent=was_disabled)
280 if self.polling and reloaded:
281 logging.info("Reloaded ganeti config")
283 # We have reloaded the config files, but received no inotify event. If
284 # an event is pending though, we just happen to have timed out before
285 # receiving it, so this is not a problem, and we shouldn't alert
286 if not self.notifier.check_events() and not was_disabled:
287 logging.warning("Config file reload at timeout (inotify failure)")
289 # We're polling, but we haven't reloaded the config:
290 # Going back to inotify mode
291 logging.debug("Moving from polling mode to inotify mode")
294 self.inotify_handler.enable()
295 except errors.InotifyError:
298 logging.debug("Performed configuration check")
302 def DisableConfd(self, silent=False):
303 """Puts confd in non-serving mode
307 logging.warning("Confd is being disabled")
308 self.processor.Disable()
312 def EnableConfd(self):
313 self.processor.Enable()
314 logging.warning("Confd is being enabled")
319 def CheckConfd(options, args):
320 """Initial checks whether to run exit with a failure.
323 # TODO: collapse HMAC daemons handling in daemons GenericMain, when we'll
324 # have more than one.
325 if not os.path.isfile(constants.HMAC_CLUSTER_KEY):
326 print >> sys.stderr, "Need HMAC key %s to run" % constants.HMAC_CLUSTER_KEY
327 sys.exit(constants.EXIT_FAILURE)
330 def ExecConfd(options, args):
331 """Main confd function, executed with PID file held
334 mainloop = daemon.Mainloop()
336 # Asyncronous confd UDP server
337 processor = confd_server.ConfdProcessor()
340 except errors.ConfigurationError:
341 # If enabling the processor has failed, we can still go on, but confd will
343 logging.warning("Confd is starting in disabled mode")
345 server = ConfdAsyncUDPServer(options.bind_address, options.port, processor)
347 # Configuration reloader
348 reloader = ConfdConfigurationReloader(processor, mainloop)
354 """Main function for the confd daemon.
357 parser = OptionParser(description="Ganeti configuration daemon",
358 usage="%prog [-f] [-d] [-b ADDRESS]",
359 version="%%prog (ganeti) %s" %
360 constants.RELEASE_VERSION)
362 dirs = [(val, constants.RUN_DIRS_MODE) for val in constants.SUB_RUN_DIRS]
363 dirs.append((constants.LOCK_DIR, 1777))
364 daemon.GenericMain(constants.CONFD, parser, dirs, CheckConfd, ExecConfd)
367 if __name__ == "__main__":