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 ConfdConfigurationReloader(object):
92 """Logic to control when to reload the ganeti configuration
94 This class is able to alter between inotify and polling, to rate-limit the
95 number of reloads. When using inotify it also supports a fallback timed
96 check, to verify that the reload hasn't failed.
99 def __init__(self, processor, mainloop):
100 """Constructor for ConfdConfigurationReloader
102 @type processor: L{confd.server.ConfdProcessor}
103 @param processor: ganeti-confd ConfdProcessor
104 @type mainloop: L{daemon.Mainloop}
105 @param mainloop: ganeti-confd mainloop
108 self.processor = processor
109 self.mainloop = mainloop
112 self.last_notification = 0
114 # Asyncronous inotify handler for config changes
115 cfg_file = constants.CLUSTER_CONF_FILE
116 self.wm = pyinotify.WatchManager()
117 self.inotify_handler = asyncnotifier.SingleFileEventHandler(self.wm,
120 notifier_class = asyncnotifier.ErrorLoggingAsyncNotifier
121 self.notifier = notifier_class(self.wm, self.inotify_handler)
123 self.timer_handle = None
126 def OnInotify(self, notifier_enabled):
127 """Receive an inotify notification.
129 @type notifier_enabled: boolean
130 @param notifier_enabled: whether the notifier is still enabled
133 current_time = time.time()
134 time_delta = current_time - self.last_notification
135 self.last_notification = current_time
137 if time_delta < constants.CONFD_CONFIG_RELOAD_RATELIMIT:
138 logging.debug("Moving from inotify mode to polling mode")
141 self.inotify_handler.disable()
143 if not self.polling and not notifier_enabled:
145 self.inotify_handler.enable()
146 except errors.InotifyError:
150 reloaded = self.processor.reader.Reload()
152 logging.info("Reloaded ganeti config")
154 logging.debug("Skipped double config reload")
155 except errors.ConfigurationError:
157 self.inotify_handler.disable()
160 # Reset the timer. If we're polling it will go to the polling rate, if
161 # we're not it will delay it again to its base safe timeout.
164 def _DisableTimer(self):
165 if self.timer_handle is not None:
166 self.mainloop.scheduler.cancel(self.timer_handle)
167 self.timer_handle = None
169 def _EnableTimer(self):
171 timeout = constants.CONFD_CONFIG_RELOAD_RATELIMIT
173 timeout = constants.CONFD_CONFIG_RELOAD_TIMEOUT
175 if self.timer_handle is None:
176 self.timer_handle = self.mainloop.scheduler.enter(
177 timeout, 1, self.OnTimer, [])
179 def _ResetTimer(self):
184 """Function called when the timer fires
187 self.timer_handle = None
191 if self.processor.reader is None:
196 reloaded = self.processor.reader.Reload()
197 except errors.ConfigurationError:
198 self.DisableConfd(silent=was_disabled)
201 if self.polling and reloaded:
202 logging.info("Reloaded ganeti config")
204 # We have reloaded the config files, but received no inotify event. If
205 # an event is pending though, we just happen to have timed out before
206 # receiving it, so this is not a problem, and we shouldn't alert
207 if not self.notifier.check_events() and not was_disabled:
208 logging.warning("Config file reload at timeout (inotify failure)")
210 # We're polling, but we haven't reloaded the config:
211 # Going back to inotify mode
212 logging.debug("Moving from polling mode to inotify mode")
215 self.inotify_handler.enable()
216 except errors.InotifyError:
219 logging.debug("Performed configuration check")
223 def DisableConfd(self, silent=False):
224 """Puts confd in non-serving mode
228 logging.warning("Confd is being disabled")
229 self.processor.Disable()
233 def EnableConfd(self):
234 self.processor.Enable()
235 logging.warning("Confd is being enabled")
240 def CheckConfd(_, args):
241 """Initial checks whether to run exit with a failure.
244 if args: # confd doesn't take any arguments
245 print >> sys.stderr, ("Usage: %s [-f] [-d] [-b ADDRESS]" % sys.argv[0])
246 sys.exit(constants.EXIT_FAILURE)
248 # TODO: collapse HMAC daemons handling in daemons GenericMain, when we'll
249 # have more than one.
250 if not os.path.isfile(constants.CONFD_HMAC_KEY):
251 print >> sys.stderr, "Need HMAC key %s to run" % constants.CONFD_HMAC_KEY
252 sys.exit(constants.EXIT_FAILURE)
255 def ExecConfd(options, _):
256 """Main confd function, executed with PID file held
259 # TODO: clarify how the server and reloader variables work (they are
261 # pylint: disable-msg=W0612
262 mainloop = daemon.Mainloop()
264 # Asyncronous confd UDP server
265 processor = confd_server.ConfdProcessor()
268 except errors.ConfigurationError:
269 # If enabling the processor has failed, we can still go on, but confd will
271 logging.warning("Confd is starting in disabled mode")
273 server = ConfdAsyncUDPServer(options.bind_address, options.port, processor)
275 # Configuration reloader
276 reloader = ConfdConfigurationReloader(processor, mainloop)
282 """Main function for the confd daemon.
285 parser = OptionParser(description="Ganeti configuration daemon",
286 usage="%prog [-f] [-d] [-b ADDRESS]",
287 version="%%prog (ganeti) %s" %
288 constants.RELEASE_VERSION)
290 dirs = [(val, constants.RUN_DIRS_MODE) for val in constants.SUB_RUN_DIRS]
291 dirs.append((constants.LOCK_DIR, 1777))
292 daemon.GenericMain(constants.CONFD, parser, dirs, CheckConfd, ExecConfd)
295 if __name__ == "__main__":