1COLLECTD-EXEC(5) collectd COLLECTD-EXEC(5)
2
6 collectd-exec - Documentation of collectd's "exec plugin"
7
9 # See collectd.conf(5)
10 LoadPlugin exec
11 # ...
12 <Plugin exec>
13 Exec "myuser:mygroup" "myprog"
14 Exec "otheruser" "/path/to/another/binary" "arg0" "arg1"
15 NotificationExec "user" "/usr/lib/collectd/exec/handle_notification"
16 </Plugin>
17
19 The "exec plugin" forks of an executable either to receive values or to
20 dispatch notifications to the outside world. The syntax of the
21 configuration is explained in collectd.conf(5) but summarized in the
22 above synopsis.
23 If you want/need better performance or more functionality you should
25 take a long look at the "perl plugin", collectd-perl(5).
26
28 There are currently two types of executables that can be executed by
29 the "exec plugin":
30 "Exec"
32 These programs are forked and values that it writes to "STDOUT" are
33 read back. The executable is forked in a fashion similar to init:
34 It is forked once and not again until it exits. If it exited, it
35 will be forked again after at most Interval seconds. It is
36 perfectly legal for the executable to run for a long time and
37 continuously write values to "STDOUT".
38 See "EXEC DATA FORMAT" below for a description of the output format
40 expected from these programs.
41 Warning: If the executable only writes one value and then exits I
43 will be executed every Interval seconds. If Interval is short (the
44 default is 10 seconds) this may result in serious system load.
45 "NotificationExec"
47 The program is forked once for each notification that is handled by
48 the daemon. The notification is passed to the program on "STDIN"
49 in a fashion similar to HTTP-headers. In contrast to programs
50 specified with "Exec" the execution of this program is not
51 serialized, so that several instances of this program may run at
52 once if multiple notifications are received.
53 See "NOTIFICATION DATA FORMAT" below for a description of the data
55 passed to these programs.
56
58 The forked executable is expected to print values to "STDOUT". The
59 expected format is as follows:
60 Comments
62 Each line beginning with a "#" (hash mark) is ignored.
63 PUTVAL Identifier [OptionList] Valuelist
65 Submits one or more values (identified by Identifier, see below) to
66 the daemon which will dispatch it to all it's write-plugins.
67 An Identifier is of the form "host/plugin-instance/type-instance"
69 with both instance-parts being optional. If they're omitted the
70 hyphen must be omitted, too. plugin and each instance-part may be
71 chosen freely as long as the tuple (plugin, plugin instance, type
72 instance) uniquely identifies the plugin within collectd. type
73 identifies the type and number of values (i. e. data-set) passed to
74 collectd. A large list of predefined data-sets is available in the
75 types.db file. See types.db(5) for a description of the format of
76 this file.
77 The OptionList is an optional list of Options, where each option is
79 a key-value-pair. A list of currently understood options can be
80 found below, all other options will be ignored. Values that contain
81 spaces must be quoted with double quotes.
82 Valuelist is a colon-separated list of the time and the values,
84 each either an integer if the data-source is a counter, or a double
85 if the data-source is of type "gauge". You can submit an undefined
86 gauge-value by using U. When submitting U to a counter the behavior
87 is undefined. The time is given as epoch (i. e. standard UNIX
88 time).
89 You can mix options and values, but the order is important: Options
91 only effect following values, so specifying an option as last field
92 is allowed, but useless. Also, an option applies to all following
93 values, so you don't need to re-set an option over and over again.
94 The currently defined Options are:
96 interval=seconds
98 Gives the interval in which the data identified by Identifier
99 is being collected.
100 Please note that this is the same format as used in the unixsock
102 plugin, see collectd-unixsock(5). There's also a bit more
103 information on identifiers in case you're confused.
104 Since examples usually let one understand a lot better, here are
106 some:
107 leeloo/cpu-0/cpu-idle N:2299366
109 alice/interface/if_octets-eth0 interval=10 1180647081:421465:479194
110 Since this action was the only one supported with older versions of
112 the "exec plugin" all lines were treated as if they were prefixed
113 with PUTVAL. This is still the case to maintain backwards
114 compatibility but deprecated.
115 PUTNOTIF [OptionList] message=Message
117 Submits a notification to the daemon which will then dispatch it to
118 all plugins which have registered for receiving notifications.
119 The PUTNOTIF if followed by a list of options which further
121 describe the notification. The message option is special in that it
122 will consume the rest of the line as its value. The message,
123 severity, and time options are mandatory.
124 Valid options are:
126 message=Message (REQUIRED)
128 Sets the message of the notification. This is the message that
129 will be made accessible to the user, so it should contain some
130 useful information. As with all options: If the message
131 includes spaces, it must be quoted with double quotes. This
132 option is mandatory.
133 severity=failure|warning|okay (REQUIRED)
135 Sets the severity of the notification. This option is
136 mandatory.
137 time=Time (REQUIRED)
139 Sets the time of the notification. The time is given as
140 "epoch", i. e. as seconds since January 1st, 1970, 00:00:00.
141 This option is mandatory.
142 host=Hostname
144 plugin=Plugin
145 plugin_instance=Plugin-Instance
146 type=Type
147 type_instance=Type-Instance
148 These "associative" options establish a relation between this
149 notification and collected performance data. This connection is
150 purely informal, i. e. the daemon itself doesn't do anything
151 with this information. However, websites or GUIs may use this
152 information to place notifications near the affected graph or
153 table. All the options are optional, but plugin_instance
154 without plugin or type_instance without type doesn't make much
155 sense and should be avoided.
156 Please note that this is the same format as used in the unixsock
158 plugin, see collectd-unixsock(5).
159 When collectd exits it sends a SIGTERM to all still running child-
161 processes upon which they have to quit.
162
164 The notification executables receive values rather than providing them.
165 In fact, after the program is started "STDOUT" is connected to
166 "/dev/null".
167 The data is passed to the executables over "STDIN" in a format very
169 similar to HTTP: At first there is a "header" with one line per field.
170 Every line consists of a field name, ended by a colon, and the
171 associated value until end-of-line. The "header" is ended by two
172 newlines immediately following another, i. e. an empty line. The rest,
173 basically the "body", is the message of the notification.
174 The following is an example notification passed to a program:
176 Severity: FAILURE
178 Time: 1200928930
179 Host: myhost.mydomain.org
180 \n
181 This is a test notification to demonstrate the format
182 The following header files are currently used. Please note, however,
184 that you should ignore unknown header files to be as forward-compatible
185 as possible.
186 Severity
188 Severity of the notification. May either be FAILURE, WARNING, or
189 OKAY.
190 Time
192 The time in epoch, i. e. as seconds since 1970-01-01 00:00:00 UTC.
193 Host
195 Plugin
196 PluginInstance
197 Type
198 TypeInstance
199 Identification of the performance data this notification is
200 associated with. All of these fields are optional because
201 notifications do not need to be associated with a certain value.
202
204 The following environment variables are set by the plugin before
205 calling exec:
206 COLLECTD_INTERVAL
208 Value of the global interval setting.
209 COLLECTD_HOSTNAME
211 Hostname used by collectd to dispatch local values.
212
214 Though the interface is far from perfect, there are tons of plugins for
215 Nagios. You can use these plugins with collectd by using a simple
216 transition layer, "exec-nagios.px", which is shipped with the collectd
217 distribution in the "contrib/" directory. It is a simple Perl script
218 that comes with embedded documentation. To see it, run the following
219 command:
220 perldoc exec-nagios.px
222 This script expects a configuration file, "exec-nagios.conf". You can
224 find an example in the "contrib/" directory, too.
225 Even a simple mechanism to submit "performance data" to collectd is
227 implemented. If you need a more sophisticated setup, please rewrite the
228 plugin to make use of collectd's more powerful interface.
229
231 ยท The user, the binary is executed as, may not have root privileges,
232 i. e. must have an UID that is non-zero. This is for your own
233 good.
234
236 collectd(1), collectd.conf(5), collectd-perl(5), collectd-unixsock(5),
237 fork(2), exec(3)
238
240 Florian Forster <octo@verplant.org>
2414.9.5 2011-03-26 COLLECTD-EXEC(5)