collectd is a daemon that receives system statistics and makes them available
in a number of ways. The main daemon itself doesn't have any real functionality
-appart from loading, querying and submitting to plugins. For a description of
+apart from loading, querying and submitting to plugins. For a description of
available plugins please see L</PLUGINS> below.
=head1 OPTIONS
change B<collectd>'s behavior. The path may be relative to the current working
directory.
+=item B<-t>
+
+Test the configuration only. The program immediately exits after parsing the
+config file. A return code not equal to zero indicates an error.
+
=item B<-P> I<E<lt>pid-fileE<gt>>
Specify an alternative pid file. This overwrites any settings in the config
Don't fork to the background. I<collectd> will also B<not> close standard file
descriptors, detach from the session nor write a pid file. This is mainly
-thought for 'supervisioning' init replacements such as I<runit>.
+thought for 'supervising' init replacements such as I<runit>.
=item B<-h>
=head1 PLUGINS
-As noted above, the real power of collectd lies within it's plugins. There are
-two big groups of plugins, B<input> and B<output> plugins:
+As noted above, the real power of collectd lies within it's plugins. A
+(hopefully complete) list of plugins and short descriptions can be found in the
+F<README> file that is distributed with the sourcecode. If you're using a
+package it's a good bet to search somewhere near F</usr/share/doc/collectd>.
+
+There are two big groups of plugins, B<input> and B<output> plugins:
=over 4
=item
-Input plugins are queried periodically. They somehow aquire the current value
+Input plugins are queried periodically. They somehow acquire the current value
of whatever they where designed to work with and submit these values back to
the daemon, i. e. they "dispatch" the values. As an example, the C<cpu plugin>
reads the current cpu-counters of time spent in the various modes (user,
C<network plugin>, for example, is able to send (i.E<nbsp>e. "write") B<and>
receive (i.E<nbsp>e. "dispatch") values. Also, it opens a socket upon
initialization and dispatches the values when it receives them and isn't
-triggered at the same time the input plugins are being read. You can think if
+triggered at the same time the input plugins are being read. You can think of
the network receive part as working asynchronous if it helps.
In addition to the above, there are "logging plugins". Right now those are the
Please note that some plugins, that provide other means of communicating with
the daemon, have manpages of their own to describe their functionality in more
-detail. In particular those are L<collectd-exec(5)>, L<collectd-unixsock(5)>,
-...
-
-=head1 SPECIAL PLUGINS
-
-=head2 apache
-
-This module connects to an Apache or lighttpd webserver and expects the output
-produced by B<mod_status.c>. If requires B<libcurl> to set up the HTTP
-connection and issue the request(s). The following is a sample config for the
-Apache webserver. Under Apache, the use of C<ExtendedStatus on> is mandatory.
-
- ExtendedStatus on
- <IfModule mod_status.c>
- <Location /mod_status>
- SetHandler server-status
- </Location>
- </IfModule>
-
-This plugin requires further configuration. Please read L<collectd.conf(5)>.
-
-=head2 cpufreq
-
-This module reads F</sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq> (for
-the first CPU installed) to get the current CPU frequency. If this file does
-not exist make sure B<cpufreqd> (L<http://cpufreqd.sourceforge.net/>) or a
-similar tool is installed and an "cpu governor" (that's kernel module) is
-loaded.
-
-=head2 email
-
-This plugin collects data indirectly by providing a UNIX socket that external
-programs can connect to. A simple line based protocol is used to communicate
-with the plugin:
-
-E-Mail type (e.g. "ham", "spam", "virus", ...) and size (bytes):
-
- e:<type>:<size>
-
-If C<size> is less than or equal to zero, C<size> is ignored.
-
-Spam score:
-
- s:<value>
-
-Successful spam checks (e.g. "BAYES_99", "SUBJECT_DRUG_GAP_C", ...):
-
- c:<type1>[,<type2>,...]
-
-Each line is limited to 256 characters (including the newline character).
-Longer lines will be ignored.
-
-=head2 mysql
-
-Requires B<mysqlclient> to be installed. It connects to the database when
-started and keeps the connection up as long as possible. When the connection is
-interrupted for whatever reason it will try to re-connect. The syslog will
-contain loud complaints in case anything goes wrong.
-
-This plugin issues C<SHOW STATUS> and evaluates C<Bytes_{received,sent}>,
-C<Com_*> and C<Handler_*> which correspond to F<traffic-mysql.rrd>,
-F<mysql_commands-*.rrd> and F<mysql_handler-*.rrd>. Also, the values of
-C<Qcache_*> are put in F<mysql_qcache.rrd> and values of C<Threads_*> are put
-in F<mysql_threads.rrd>. Please refer to the B<MySQL reference manual>,
-I<5.2.4. Server Status Variables> for an explanation of these values.
-
-=head2 perl
-
-The C<perl plugin> includes a Perl-interpreter in collectd and provides
-Perl-equivalents of the plugin-functions. This makes it possible to write
-plugins in Perl.
-
-There are two more complex types you need to know about:
-
-=over 4
-
-=item Data-Set
-
-A data-set is a list of one or more data-sources. Each data-source defines a
-name, type, min- and max-value and the data-set wraps them up into one
-structure. The general layout looks like this:
-
- [{
- name => 'data_source_name',
- type => DS_TYPE_COUNTER || DS_TYPE_GAUGE
- min => value || undef,
- max => value || undef
- }, ...]
-
-=item Value-List
-
-A value-list is one structure which features an array of values and fields to
-identify the values, i. e. time and host, plugin name and plugin-instance as
-well as a type and type-instance. Since the "type" is not included in the
-value-list but is passed as an extra argument, the general layout looks like
-this:
-
- {
- values => [123, 0.5],
- time => time (),
- host => 'localhost',
- plugin => 'myplugin',
- plugin_instance => '',
- type_instance => ''
- }
-
-=back
-
-The following functions provide the C-interface to Perl-modules:
-
-=over 4
-
-=item B<plugin_register> (I<type>, I<name>, I<data>)
-
-Registers a callback-function or data-set.
-
-I<type> can be one of:
-
-=over 4
-
-=item TYPE_INIT
-
-=item TYPE_READ
-
-=item TYPE_WRITE
-
-=item TYPE_LOG
-
-=item TYPE_SHUTDOWN
-
-=item TYPE_DATASET
-
-=back
-
-I<name> is the name of the callback-function or the type of the data-set,
-depending on the value of I<type>. (Please note that the type of the data-set
-is the value passed as I<name> here and has nothing to do with the I<type>
-argument which simply tells B<plugin_register> what is being registered.)
-
-The last argument, I<data>, is either a function- or an array-reference. If
-I<type> is B<TYPE_DATASET>, then the I<data> argument must be an
-array-reference which points to an array of hashes. Each hash describes one
-data-source. For the exact layout see B<Data-Set> above.
-
-If the I<type> argument is any of the other types (B<TYPE_INIT>, B<TYPE_READ>,
-...) then I<data> is expected to be a function reference. These functions are
-called in the various stages of the daemon and are passed the following
-arguments:
-
-=over 4
-
-=item TYPE_INIT
-
-=item TYPE_READ
-
-=item TYPE_SHUTDOWN
-
-No arguments are passed
-
-=item TYPE_WRITE
-
-The arguments passed are I<type>, I<data-set>, and I<value-list>. I<type> is a
-string. For the layout of I<data-set> and I<value-list> see above.
-
-=item TYPE_LOG
-
-The arguments are I<log-level> and I<message>. The log level is small for
-important messages and high for less important messages. The least important
-level is B<LOG_DEBUG>, the most important level is B<LOG_ERR>. In between there
-are (from least to most important): B<LOG_INFO>, B<LOG_NOTICE>, and
-B<LOG_WARNING>. I<message> is simply a string B<without> a newline at the end.
-
-=back
-
-=item B<plugin_unregister> (I<type>, I<plugin>)
-
-Removes a callback or data-set from collectd's internal list of
-functionsE<nbsp>/ datasets.
-
-=item B<plugin_dispatch_values> (I<type>, I<value-list>)
-
-Submits a I<value-list> of type I<type> to the daemon. If the data-set I<type>
-is found (and the number of values matches the number of data-sources) then the
-type, data-set and value-list is passed to all write-callbacks that are
-registered with the daemon.
-
-=item B<plugin_log> (I<log-level>, I<message>)
-
-Submits a I<message> of level I<log-level> to collectd's logging mechanism.
-The message is passed to all log-callbacks that are registered with collectd.
-
-=back
-
-=head2 sensors
-
-The B<sensors> module uses lm_sensors to retrieve sensor-values. This means
-that all the needed modules have to be loaded and lm_sensors has to be
-configured (most likely by editing F</etc/sensors.conf>. Read
-L<sensors.conf(5)> for details.
-
-The B<lm_sensors> homepage can be found at
-L<http://secure.netroedge.com/~lm78/>.
-
-=head2 mbmon
-
-The B<mbmon> module uses mbmon to retrieve temperature, voltage, etc.
-
-collectd connects to B<localhost> (127.0.0.1), port B<411/tcp>.
-The B<Host> and B<Port> options can be used to change these
-default values. See L<collectd.conf(5)> for details. C<mbmon> has to be
-running to work correctly. If C<mbmon> is not running timeouts may appear
-which may interfere with other statistics..
-
-C<mbmon> must be run with the -r option ("print TAG and Value format");
-Debian's /etc/init.d/mbmon script already does this, other people
-will need to ensure that this is the case.
-
-=head2 hddtemp
-
-To get values from B<hddtemp> collectd connects to B<localhost> (127.0.0.1),
-port B<7634/tcp>. The B<Host> and B<Port> options can be used to change these
-default values. See L<collectd.conf(5)> for details. C<hddtemp> has to be
-running to work correctly. If C<hddtemp> is not running timeouts may appear
-which may interfere with other statistics..
-
-The B<hddtemp> homepage can be found at
-L<http://www.guzu.net/linux/hddtemp.php>.
-
-=head2 vserver
-
-B<VServer> support is only available for Linux. It cannot yet be found in a
-vanilla kernel, though. To make use of this plugin you need a kernel that has
-B<VServer> support built in, i.e. you need to apply the patches and compile
-your own kernel, which will then provide the /proc/virtual filesystem that is
-required by this plugin.
-
-The B<VServer> homepage can be found at L<http://linux-vserver.org/>.
+detail. In particular those are L<collectd-email(5)>, L<collectd-exec(5)>,
+L<collectd-perl(5)>, and L<collectd-unixsock(5)>
=head1 SEE ALSO
L<collectd.conf(5)>,
+L<collectd-email(5)>,
L<collectd-exec(5)>,
+L<collectd-perl(5)>,
L<collectd-unixsock(5)>,
-L<hddtemp(8)>,
-L<kstat(3KSTAT)>,
-L<mbmon(1)>,
-L<rrdtool(1)>,
-L<sensors(1)>,
L<http://collectd.org/>
=head1 AUTHOR
projects / collectd.git / blobdiff