root / daemons / ganeti-confd @ 4d5db19c
History | View | Annotate | Download (7.9 kB)
1 |
#!/usr/bin/python |
---|---|
2 |
# |
3 |
|
4 |
# Copyright (C) 2009, Google Inc. |
5 |
# |
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. |
10 |
# |
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. |
15 |
# |
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 |
19 |
# 02110-1301, USA. |
20 |
|
21 |
|
22 |
"""Ganeti configuration daemon |
23 |
|
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. |
26 |
|
27 |
""" |
28 |
|
29 |
import os |
30 |
import sys |
31 |
import logging |
32 |
import asyncore |
33 |
import socket |
34 |
import pyinotify |
35 |
|
36 |
from optparse import OptionParser |
37 |
|
38 |
from ganeti import constants |
39 |
from ganeti import errors |
40 |
from ganeti import daemon |
41 |
from ganeti import ssconf |
42 |
from ganeti.asyncnotifier import AsyncNotifier |
43 |
from ganeti.confd.server import ConfdProcessor |
44 |
|
45 |
|
46 |
class ConfdAsyncUDPServer(asyncore.dispatcher): |
47 |
"""The confd udp server, suitable for use with asyncore. |
48 |
|
49 |
""" |
50 |
def __init__(self, bind_address, port, processor): |
51 |
"""Constructor for ConfdAsyncUDPServer |
52 |
|
53 |
@type bind_address: string |
54 |
@param bind_address: socket bind address ('' for all) |
55 |
@type port: int |
56 |
@param port: udp port |
57 |
@type processor: L{confd.server.ConfdProcessor} |
58 |
@param reader: ConfigReader to use to access the config |
59 |
|
60 |
""" |
61 |
asyncore.dispatcher.__init__(self) |
62 |
self.bind_address = bind_address |
63 |
self.port = port |
64 |
self.processor = processor |
65 |
self.create_socket(socket.AF_INET, socket.SOCK_DGRAM) |
66 |
self.bind((bind_address, port)) |
67 |
logging.debug("listening on ('%s':%d)" % (bind_address, port)) |
68 |
|
69 |
# this method is overriding an asyncore.dispatcher method |
70 |
def handle_connect(self): |
71 |
# Python thinks that the first udp message from a source qualifies as a |
72 |
# "connect" and further ones are part of the same connection. We beg to |
73 |
# differ and treat all messages equally. |
74 |
pass |
75 |
|
76 |
# this method is overriding an asyncore.dispatcher method |
77 |
def handle_read(self): |
78 |
try: |
79 |
payload_in, address = self.recvfrom(4096) |
80 |
ip, port = address |
81 |
payload_out = self.processor.ExecQuery(payload_in, ip, port) |
82 |
if payload_out is not None: |
83 |
self.sendto(payload_out, 0, (ip, port)) |
84 |
except: |
85 |
# we need to catch any exception here, log it, but proceed, because even |
86 |
# if we failed handling a single request, we still want the confd to |
87 |
# continue working. |
88 |
logging.error("Unexpected exception", exc_info=True) |
89 |
|
90 |
# this method is overriding an asyncore.dispatcher method |
91 |
def writable(self): |
92 |
# No need to check if we can write to the UDP socket |
93 |
return False |
94 |
|
95 |
|
96 |
class ConfdInotifyEventHandler(pyinotify.ProcessEvent): |
97 |
|
98 |
def __init__(self, watch_manager, reader, |
99 |
file=constants.CLUSTER_CONF_FILE): |
100 |
"""Constructor for ConfdInotifyEventHandler |
101 |
|
102 |
@type watch_manager: L{pyinotify.WatchManager} |
103 |
@param watch_manager: ganeti-confd inotify watch manager |
104 |
@type reader: L{ssconf.SimpleConfigReader} |
105 |
@param reader: ganeti-confd SimpleConfigReader |
106 |
@type file: string |
107 |
@param file: config file to watch |
108 |
|
109 |
""" |
110 |
# no need to call the parent's constructor |
111 |
self.watch_manager = watch_manager |
112 |
self.reader = reader |
113 |
self.mask = pyinotify.EventsCodes.IN_IGNORED | \ |
114 |
pyinotify.EventsCodes.IN_MODIFY |
115 |
self.file = file |
116 |
self.add_config_watch() |
117 |
|
118 |
def add_config_watch(self): |
119 |
"""Add a watcher for the ganeti config file |
120 |
|
121 |
""" |
122 |
result = self.watch_manager.add_watch(self.file, self.mask) |
123 |
if not result[self.file] > 0: |
124 |
raise errors.ConfdFatalError("Could not add inotify watcher") |
125 |
|
126 |
def reload_config(self): |
127 |
try: |
128 |
reloaded = self.reader.Reload() |
129 |
if reloaded: |
130 |
logging.info("Reloaded ganeti config") |
131 |
else: |
132 |
logging.debug("Skipped double config reload") |
133 |
except errors.ConfigurationError: |
134 |
# transform a ConfigurationError in a fatal error, that will cause confd |
135 |
# to quit. |
136 |
raise errors.ConfdFatalError(err) |
137 |
|
138 |
def process_IN_IGNORED(self, event): |
139 |
# Due to the fact that we monitor just for the cluster config file (rather |
140 |
# than for the whole data dir) when the file is replaced with another one |
141 |
# (which is what happens normally in ganeti) we're going to receive an |
142 |
# IN_IGNORED event from inotify, because of the file removal (which is |
143 |
# contextual with the replacement). In such a case we need to create |
144 |
# another watcher for the "new" file. |
145 |
logging.debug("Received 'ignored' inotify event for %s" % event.path) |
146 |
|
147 |
try: |
148 |
# Since the kernel believes the file we were interested in is gone, it's |
149 |
# not going to notify us of any other events, until we set up, here, the |
150 |
# new watch. This is not a race condition, though, since we're anyway |
151 |
# going to realod the file after setting up the new watch. |
152 |
self.add_config_watch() |
153 |
self.reload_config() |
154 |
except errors.ConfdFatalError, err: |
155 |
logging.critical("Critical error, shutting down: %s" % err) |
156 |
sys.exit(constants.EXIT_FAILURE) |
157 |
except: |
158 |
# we need to catch any exception here, log it, but proceed, because even |
159 |
# if we failed handling a single request, we still want the confd to |
160 |
# continue working. |
161 |
logging.error("Unexpected exception", exc_info=True) |
162 |
|
163 |
def process_IN_MODIFY(self, event): |
164 |
# This gets called when the config file is modified. Note that this doesn't |
165 |
# usually happen in Ganeti, as the config file is normally replaced by a |
166 |
# new one, at filesystem level, rather than actually modified (see |
167 |
# utils.WriteFile) |
168 |
logging.debug("Received 'modify' inotify event for %s" % event.path) |
169 |
|
170 |
try: |
171 |
self.reload_config() |
172 |
except errors.ConfdFatalError, err: |
173 |
logging.critical("Critical error, shutting down: %s" % err) |
174 |
sys.exit(constants.EXIT_FAILURE) |
175 |
except: |
176 |
# we need to catch any exception here, log it, but proceed, because even |
177 |
# if we failed handling a single request, we still want the confd to |
178 |
# continue working. |
179 |
logging.error("Unexpected exception", exc_info=True) |
180 |
|
181 |
def process_default(self, event): |
182 |
logging.error("Received unhandled inotify event: %s" % event) |
183 |
|
184 |
|
185 |
def CheckCONFD(options, args): |
186 |
"""Initial checks whether to run exit with a failure |
187 |
|
188 |
""" |
189 |
# TODO: collapse HMAC daemons handling in daemons GenericMain, when we'll |
190 |
# have more than one. |
191 |
if not os.path.isfile(constants.HMAC_CLUSTER_KEY): |
192 |
print >> sys.stderr, "Need HMAC key %s to run" % constants.HMAC_CLUSTER_KEY |
193 |
sys.exit(constants.EXIT_FAILURE) |
194 |
|
195 |
ssconf.CheckMasterCandidate(options.debug) |
196 |
|
197 |
|
198 |
def ExecCONFD(options, args): |
199 |
"""Main CONFD function, executed with pidfile held |
200 |
|
201 |
""" |
202 |
# confd-level SimpleConfigReader |
203 |
reader = ssconf.SimpleConfigReader() |
204 |
|
205 |
# Asyncronous confd UDP server |
206 |
processor = ConfdProcessor(reader) |
207 |
server = ConfdAsyncUDPServer(options.bind_address, options.port, processor) |
208 |
|
209 |
# Asyncronous inotify handler for config changes |
210 |
wm = pyinotify.WatchManager() |
211 |
confd_event_handler = ConfdInotifyEventHandler(wm, reader) |
212 |
notifier = AsyncNotifier(wm, confd_event_handler) |
213 |
asyncore.loop() |
214 |
|
215 |
|
216 |
def main(): |
217 |
"""Main function for the confd daemon. |
218 |
|
219 |
""" |
220 |
parser = OptionParser(description="Ganeti configuration daemon", |
221 |
usage="%prog [-f] [-d] [-b ADDRESS]", |
222 |
version="%%prog (ganeti) %s" % |
223 |
constants.RELEASE_VERSION) |
224 |
|
225 |
dirs = [(val, constants.RUN_DIRS_MODE) for val in constants.SUB_RUN_DIRS] |
226 |
dirs.append((constants.LOG_OS_DIR, 0750)) |
227 |
dirs.append((constants.LOCK_DIR, 1777)) |
228 |
daemon.GenericMain(constants.CONFD, parser, dirs, CheckCONFD, ExecCONFD) |
229 |
|
230 |
|
231 |
if __name__ == '__main__': |
232 |
main() |