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 pyinotify import pyinotify
39 from optparse import OptionParser
41 from ganeti import asyncnotifier
42 from ganeti import confd
43 from ganeti.confd import server as confd_server
44 from ganeti import constants
45 from ganeti import errors
46 from ganeti import daemon
47 from ganeti import ssconf
50 class ConfdAsyncUDPServer(daemon.AsyncUDPSocket):
51 """The confd udp server, suitable for use with asyncore.
54 def __init__(self, bind_address, port, processor):
55 """Constructor for ConfdAsyncUDPServer
57 @type bind_address: string
58 @param bind_address: socket bind address ('' for all)
61 @type processor: L{confd.server.ConfdProcessor}
62 @param processor: ConfdProcessor to use to handle queries
65 daemon.AsyncUDPSocket.__init__(self)
66 self.bind_address = bind_address
68 self.processor = processor
69 self.bind((bind_address, port))
70 logging.debug("listening on ('%s':%d)" % (bind_address, port))
72 # this method is overriding a daemon.AsyncUDPSocket method
73 def handle_datagram(self, payload_in, ip, port):
75 query = confd.UnpackMagic(payload_in)
76 except errors.ConfdMagicError, err:
80 answer = self.processor.ExecQuery(query, ip, port)
81 if answer is not None:
83 self.enqueue_send(ip, port, confd.PackMagic(answer))
84 except errors.UdpDataSizeError:
85 logging.error("Reply too big to fit in an udp packet.")
88 class ConfdInotifyEventHandler(pyinotify.ProcessEvent):
90 def __init__(self, watch_manager, callback,
91 file=constants.CLUSTER_CONF_FILE):
92 """Constructor for ConfdInotifyEventHandler
94 @type watch_manager: L{pyinotify.WatchManager}
95 @param watch_manager: ganeti-confd inotify watch manager
96 @type callback: function accepting a boolean
97 @param callback: function to call when an inotify event happens
99 @param file: config file to watch
102 # no need to call the parent's constructor
103 self.watch_manager = watch_manager
104 self.callback = callback
105 self.mask = pyinotify.EventsCodes.IN_IGNORED | \
106 pyinotify.EventsCodes.IN_MODIFY
108 self.watch_handle = None
111 """Watch the given file
114 if self.watch_handle is None:
115 result = self.watch_manager.add_watch(self.file, self.mask)
116 if not self.file in result or result[self.file] <= 0:
117 raise errors.InotifyError("Could not add inotify watcher")
119 self.watch_handle = result[self.file]
122 """Stop watching the given file
125 if self.watch_handle is not None:
126 result = self.watch_manager.rm_watch(self.watch_handle)
127 if result[self.watch_handle]:
128 self.watch_handle = None
130 def process_IN_IGNORED(self, event):
131 # Due to the fact that we monitor just for the cluster config file (rather
132 # than for the whole data dir) when the file is replaced with another one
133 # (which is what happens normally in ganeti) we're going to receive an
134 # IN_IGNORED event from inotify, because of the file removal (which is
135 # contextual with the replacement). In such a case we need to create
136 # another watcher for the "new" file.
137 logging.debug("Received 'ignored' inotify event for %s" % event.path)
138 self.watch_handle = None
141 # Since the kernel believes the file we were interested in is gone, it's
142 # not going to notify us of any other events, until we set up, here, the
143 # new watch. This is not a race condition, though, since we're anyway
144 # going to realod the file after setting up the new watch.
146 except errors.ConfdFatalError, err:
147 logging.critical("Critical error, shutting down: %s" % err)
148 sys.exit(constants.EXIT_FAILURE)
150 # we need to catch any exception here, log it, but proceed, because even
151 # if we failed handling a single request, we still want the confd to
153 logging.error("Unexpected exception", exc_info=True)
155 def process_IN_MODIFY(self, event):
156 # This gets called when the config file is modified. Note that this doesn't
157 # usually happen in Ganeti, as the config file is normally replaced by a
158 # new one, at filesystem level, rather than actually modified (see
160 logging.debug("Received 'modify' inotify event for %s" % event.path)
164 except errors.ConfdFatalError, err:
165 logging.critical("Critical error, shutting down: %s" % err)
166 sys.exit(constants.EXIT_FAILURE)
168 # we need to catch any exception here, log it, but proceed, because even
169 # if we failed handling a single request, we still want the confd to
171 logging.error("Unexpected exception", exc_info=True)
173 def process_default(self, event):
174 logging.error("Received unhandled inotify event: %s" % event)
177 class ConfdConfigurationReloader(object):
178 """Logic to control when to reload the ganeti configuration
180 This class is able to alter between inotify and polling, to rate-limit the
181 number of reloads. When using inotify it also supports a fallback timed
182 check, to verify that the reload hasn't failed.
185 def __init__(self, processor, mainloop):
186 """Constructor for ConfdConfigurationReloader
188 @type processor: L{confd.server.ConfdProcessor}
189 @param processor: ganeti-confd ConfdProcessor
190 @type mainloop: L{daemon.Mainloop}
191 @param mainloop: ganeti-confd mainloop
194 self.processor = processor
195 self.mainloop = mainloop
198 self.last_notification = 0
200 # Asyncronous inotify handler for config changes
201 self.wm = pyinotify.WatchManager()
202 self.inotify_handler = ConfdInotifyEventHandler(self.wm, self.OnInotify)
203 self.notifier = asyncnotifier.AsyncNotifier(self.wm, self.inotify_handler)
205 self.timer_handle = None
208 def OnInotify(self, notifier_enabled):
209 """Receive an inotify notification.
211 @type notifier_enabled: boolean
212 @param notifier_enabled: whether the notifier is still enabled
215 current_time = time.time()
216 time_delta = current_time - self.last_notification
217 self.last_notification = current_time
219 if time_delta < constants.CONFD_CONFIG_RELOAD_RATELIMIT:
220 logging.debug("Moving from inotify mode to polling mode")
223 self.inotify_handler.disable()
225 if not self.polling and not notifier_enabled:
227 self.inotify_handler.enable()
228 except errors.InotifyError:
232 reloaded = self.processor.reader.Reload()
234 logging.info("Reloaded ganeti config")
236 logging.debug("Skipped double config reload")
237 except errors.ConfigurationError:
239 self.inotify_handler.disable()
242 # Reset the timer. If we're polling it will go to the polling rate, if
243 # we're not it will delay it again to its base safe timeout.
246 def _DisableTimer(self):
247 if self.timer_handle is not None:
248 self.mainloop.scheduler.cancel(self.timer_handle)
249 self.timer_handle = None
251 def _EnableTimer(self):
253 timeout = constants.CONFD_CONFIG_RELOAD_RATELIMIT
255 timeout = constants.CONFD_CONFIG_RELOAD_TIMEOUT
257 if self.timer_handle is None:
258 self.timer_handle = self.mainloop.scheduler.enter(
259 timeout, 1, self.OnTimer, [])
261 def _ResetTimer(self):
266 """Function called when the timer fires
269 self.timer_handle = None
273 if self.processor.reader is None:
278 reloaded = self.processor.reader.Reload()
279 except errors.ConfigurationError:
280 self.DisableConfd(silent=was_disabled)
283 if self.polling and reloaded:
284 logging.info("Reloaded ganeti config")
286 # We have reloaded the config files, but received no inotify event. If
287 # an event is pending though, we just happen to have timed out before
288 # receiving it, so this is not a problem, and we shouldn't alert
289 if not self.notifier.check_events() and not was_disabled:
290 logging.warning("Config file reload at timeout (inotify failure)")
292 # We're polling, but we haven't reloaded the config:
293 # Going back to inotify mode
294 logging.debug("Moving from polling mode to inotify mode")
297 self.inotify_handler.enable()
298 except errors.InotifyError:
301 logging.debug("Performed configuration check")
305 def DisableConfd(self, silent=False):
306 """Puts confd in non-serving mode
310 logging.warning("Confd is being disabled")
311 self.processor.Disable()
315 def EnableConfd(self):
316 self.processor.Enable()
317 logging.warning("Confd is being enabled")
322 def CheckConfd(options, args):
323 """Initial checks whether to run exit with a failure.
326 # TODO: collapse HMAC daemons handling in daemons GenericMain, when we'll
327 # have more than one.
328 if not os.path.isfile(constants.HMAC_CLUSTER_KEY):
329 print >> sys.stderr, "Need HMAC key %s to run" % constants.HMAC_CLUSTER_KEY
330 sys.exit(constants.EXIT_FAILURE)
333 def ExecConfd(options, args):
334 """Main confd function, executed with PID file held
337 mainloop = daemon.Mainloop()
339 # Asyncronous confd UDP server
340 processor = confd_server.ConfdProcessor()
343 except errors.ConfigurationError:
344 # If enabling the processor has failed, we can still go on, but confd will
346 logging.warning("Confd is starting in disabled mode")
348 server = ConfdAsyncUDPServer(options.bind_address, options.port, processor)
350 # Configuration reloader
351 reloader = ConfdConfigurationReloader(processor, mainloop)
357 """Main function for the confd daemon.
360 parser = OptionParser(description="Ganeti configuration daemon",
361 usage="%prog [-f] [-d] [-b ADDRESS]",
362 version="%%prog (ganeti) %s" %
363 constants.RELEASE_VERSION)
365 dirs = [(val, constants.RUN_DIRS_MODE) for val in constants.SUB_RUN_DIRS]
366 dirs.append((constants.LOCK_DIR, 1777))
367 daemon.GenericMain(constants.CONFD, parser, dirs, CheckConfd, ExecConfd)
370 if __name__ == "__main__":