From e2be81cf2704f2ddfc4888396be20ff98e2cb1e6 Mon Sep 17 00:00:00 2001
From: Guido Trotter <ultrotter@google.com>
Date: Sun, 23 Aug 2009 20:13:55 +0300
Subject: [PATCH] Implement timers in confd
Timers are used both for checking for inotify failures, and for polling,
should inotify notices become too frequent.
Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>
---
daemons/ganeti-confd | 76 ++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 73 insertions(+), 3 deletions(-)
diff --git a/daemons/ganeti-confd b/daemons/ganeti-confd
index 34d08f33a..92170cd1e 100755
--- a/daemons/ganeti-confd
+++ b/daemons/ganeti-confd
@@ -32,6 +32,7 @@ import logging
import asyncore
import socket
import pyinotify
+import time
from optparse import OptionParser
@@ -191,20 +192,29 @@ class ConfdConfigurationReloader(object):
check, to verify that the reload hasn't failed.
"""
- def __init__(self, reader):
+ def __init__(self, reader, mainloop):
"""Constructor for ConfdConfigurationReloader
@type reader: L{ssconf.SimpleConfigReader}
@param reader: ganeti-confd SimpleConfigReader
+ @type mainloop: L{daemon.Mainloop}
+ @param mainloop: ganeti-confd mainloop
"""
self.reader = reader
+ self.mainloop = mainloop
+
+ self.polling = False
+ self.last_notification = 0
# Asyncronous inotify handler for config changes
self.wm = pyinotify.WatchManager()
self.inotify_handler = ConfdInotifyEventHandler(self.wm, self.OnInotify)
self.notifier = AsyncNotifier(self.wm, self.inotify_handler)
+ self.timer_handle = None
+ self._EnableTimer()
+
def OnInotify(self, notifier_enabled):
"""Receive an inotify notification.
@@ -212,7 +222,17 @@ class ConfdConfigurationReloader(object):
@param notifier_enabled: whether the notifier is still enabled
"""
- if not notifier_enabled:
+ current_time = time.time()
+ time_delta = current_time - self.last_notification
+ self.last_notification = current_time
+
+ if time_delta < constants.CONFD_CONFIG_RELOAD_RATELIMIT:
+ logging.debug("Moving from inotify mode to polling mode")
+ self.polling = True
+ if notifier_enabled:
+ self.confd_event_handler.disable()
+
+ if not self.polling and not notifier_enabled:
try:
self.inotify_handler.enable()
except errors.InotifyError:
@@ -229,6 +249,56 @@ class ConfdConfigurationReloader(object):
# to quit.
raise errors.ConfdFatalError(err)
+ # Reset the timer. If we're polling it will go to the polling rate, if
+ # we're not it will delay it again to its base safe timeout.
+ self._DisableTimer()
+ self._EnableTimer()
+
+ def _DisableTimer(self):
+ if self.timer_handle is not None:
+ self.mainloop.scheduler.cancel(self.timer_handle)
+ self.timer_handle = None
+
+ def _EnableTimer(self):
+ if self.polling:
+ timeout = constants.CONFD_CONFIG_RELOAD_RATELIMIT
+ else:
+ timeout = constants.CONFD_CONFIG_RELOAD_TIMEOUT
+
+ if self.timer_handle is None:
+ self.timer_handle = self.mainloop.scheduler.enter(
+ timeout, 1, self.OnTimer, [])
+
+ def OnTimer(self):
+ """Function called when the timer fires
+
+ """
+ self.timer_handle = None
+ try:
+ reloaded = self.reader.Reload()
+ except errors.ConfigurationError:
+ # transform a ConfigurationError in a fatal error, that will cause confd
+ # to quit.
+ raise errors.ConfdFatalError(err)
+
+ if self.polling and reloaded:
+ logging.info("Reloaded ganeti config")
+ elif reloaded:
+ # We have reloaded the config files, but received no inotify event. If
+ # an event is pending though, we just happen to have timed out before
+ # receiving it, so this is not a problem, and we shouldn't alert
+ if not self.notifier.check_events():
+ logging.warning("Config file reload at timeout (inotify failure)")
+ elif self.polling:
+ # We're polling, but we haven't reloaded the config:
+ # Going back to inotify mode
+ logging.debug("Moving from polling mode to inotify mode")
+ self.polling = False
+ self.inotify_handler.enable()
+ else:
+ logging.debug("Performed configuration check")
+
+ self._EnableTimer()
def CheckConfd(options, args):
@@ -258,7 +328,7 @@ def ExecConfd(options, args):
server = ConfdAsyncUDPServer(options.bind_address, options.port, processor)
# Configuration reloader
- reloader = ConfdConfigurationReloader(reader)
+ reloader = ConfdConfigurationReloader(reader, mainloop)
mainloop.Run()
--
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