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       collectd-unixsock - Documentation of collectd's "unixsock plugin"


         # See collectd.conf(5)
         LoadPlugin unixsock
         # ...
         <Plugin unixsock>
           SocketFile "/path/to/socket"
           SocketGroup "collectd"
           SocketPerms "0770"


       The "unixsock plugin" opens an UNIX-socket over which one can interact
       with the daemon. This can be used to use the values collected by
       collectd in other applications, such as monitoring solutions, or submit
       externally collected values to collectd.

       For example, this plugin is used by collectd-nagios(1) to check if some
       value is in a certain range and exit with a Nagios-compatible exit


       Upon start the "unixsock plugin" opens a UNIX-socket and waits for
       connections. Once a connection is established the client can send
       commands to the daemon which it will answer, if it understand them.

       In general the plugin answers with a status line of the following form:

       Status Message

       If Status is greater than or equal to zero the message indicates
       success, if Status is less than zero the message indicates failure.
       Message is a human-readable string that further describes the return

       On success, Status furthermore indicates the number of subsequent lines
       of output (not including the status line). Each such lines usually
       contains a single return value. See the description of each command for

       The following commands are implemented:

       GETVAL Identifier
           If the value identified by Identifier (see below) is found the
           complete value-list is returned. The response is a list of name-
           value-pairs, each pair on its own line (the number of lines is
           indicated by the status line - see above). Each name-value-pair is
           of the form name=value.  Counter-values are converted to a rate,
           e. g. bytes per second.  Undefined values are returned as NaN.

             -> | GETVAL myhost/cpu-0/cpu-user
             <- | 1 Value found
             <- | value=1.260000e+00

           Returns a list of the values available in the value cache together
           with the time of the last update, so that querying applications can
           issue a GETVAL command for the values that have changed. Each
           return value consists of the update time as an epoch value and the
           identifier, separated by a space. The update time is the time of
           the last value, as provided by the collecting instance and may be
           very different from the time the server considers to be "now".

             -> | LISTVAL
             <- | 69 Values found
             <- | 1182204284 myhost/cpu-0/cpu-idle
             <- | 1182204284 myhost/cpu-0/cpu-nice
             <- | 1182204284 myhost/cpu-0/cpu-system
             <- | 1182204284 myhost/cpu-0/cpu-user

       PUTVAL Identifier [OptionList] Valuelist
           Submits one or more values (identified by Identifier, see below) to
           the daemon which will dispatch it to all it's write-plugins.

           An Identifier is of the form "host/plugin-instance/type-instance"
           with both instance-parts being optional. If they're omitted the
           hyphen must be omitted, too. plugin and each instance-part may be
           chosen freely as long as the tuple (plugin, plugin instance, type
           instance) uniquely identifies the plugin within collectd. type
           identifies the type and number of values (i. e. data-set) passed to
           collectd. A large list of predefined data-sets is available in the
           types.db file.

           The OptionList is an optional list of Options, where each option is
           a key-value-pair. A list of currently understood options can be
           found below, all other options will be ignored. Values that contain
           spaces must be quoted with double quotes.

           Valuelist is a colon-separated list of the time and the values,
           each either an integer if the data-source is a counter, or a double
           if the data-source is of type "gauge". You can submit an undefined
           gauge-value by using U. When submitting U to a counter the behavior
           is undefined. The time is given as epoch (i. e. standard UNIX

           You can mix options and values, but the order is important: Options
           only effect following values, so specifying an option as last field
           is allowed, but useless. Also, an option applies to all following
           values, so you don't need to re-set an option over and over again.

           The currently defined Options are:

               Gives the interval in which the data identified by Identifier
               is being collected.

           Please note that this is the same format as used in the exec
           plugin, see collectd-exec(5).

             -> | PUTVAL testhost/interface/if_octets-test0 interval=10
             <- | 0 Success

       PUTNOTIF [OptionList] message=Message
           Submits a notification to the daemon which will then dispatch it to
           all plugins which have registered for receiving notifications.

           The PUTNOTIF command is followed by a list of options which further
           describe the notification. The message option is special in that it
           will consume the rest of the line as its value. The message,
           severity, and time options are mandatory.

           Valid options are:

           message=Message (REQUIRED)
               Sets the message of the notification. This is the message that
               will be made accessible to the user, so it should contain some
               useful information. As with all options: If the message
               includes spaces, it must be quoted with double quotes. This
               option is mandatory.

           severity=failure|warning|okay (REQUIRED)
               Sets the severity of the notification. This option is

           time=Time (REQUIRED)
               Sets the time of the notification. The time is given as
               "epoch", i. e. as seconds since January 1st, 1970, 00:00:00.
               This option is mandatory.

               These "associative" options establish a relation between this
               notification and collected performance data. This connection is
               purely informal, i. e. the daemon itself doesn't do anything
               with this information. However, websites or GUIs may use this
               information to place notifications near the affected graph or
               table. All the options are optional, but plugin_instance
               without plugin or type_instance without type doesn't make much
               sense and should be avoided.

               Please note that this is the same format as used in the exec
               plugin, see collectd-exec(5).

             -> | PUTNOTIF type=temperature severity=warning time=1201094702
           message=The roof is on fire!
             <- | 0 Success

       FLUSH [timeout=Timeout] [plugin=Plugin [...]] [identifier=Ident [...]]
           Flushes all cached data older than Timeout seconds. If no timeout
           has been specified, it defaults to -1 which causes all data to be

           If the plugin option has been specified, only the Plugin plugin
           will be flushed. You can have multiple plugin options to flush
           multiple plugins in one go. If the plugin option is not given all
           plugins providing a flush callback will be flushed.

           If the identifier option is given only the specified values will be
           flushed.  This is meant to be used by graphing or displaying
           frontends which want to have the latest values for a specific
           graph. Again, you can specify the identifier option multiple times
           to flush several values. If this option is not specified at all,
           all values will be flushed.

             -> | FLUSH plugin=rrdtool identifier=localhost/df/df-root
             <- | 0 Done: 2 successful, 0 errors

       Value or value-lists are identified in a uniform fashion:


       Where Plugin and Type are both either of type "Name" or
       "Name-Instance". If the identifier includes spaces, it must be quoted
       using double quotes. This sounds more complicated than it is, so here
       are some examples:

         "myups/snmp/temperature-Outlet 1"


       collectd ships the Perl-Module Collectd::Unixsock which provides an
       abstraction layer over the actual socket connection. It can be found in
       the directory bindings/perl/ in the source distribution or (usually)
       somewhere near /usr/share/perl5/ if you're using a package. If you want
       to use Perl to communicate with the daemon, you're encouraged to use
       and expand this module.


       collectd(1), collectd.conf(5), collectd-nagios(1), unix(7)


       Florian Forster <>