## <a id="setting-up-check-plugins"></a> Setting up Check Plugins

On its own Icinga 2 does not know how to check external services. The
[Monitoring Plugins Project](https://www.monitoring-plugins.org/) (former
Nagios Plugins) provides an extensive set of plugins which can be used by
Icinga 2 to check whether services are working properly.

The recommended way of installing these standard plugins is to use your
distribution's package manager.

> **Note**
>
> The `Nagios Plugins` project was renamed to `Monitoring Plugins` project
> in Jan 2014. Therefore package names may still reflect the old name.

For your convenience here is a list of package names for some of the more
popular operating systems/distributions:

OS/Distribution        | Package Name       | Installation Path
-----------------------|--------------------|---------------------------
RHEL/CentOS (EPEL)     | nagios-plugins-all | /usr/lib/nagios/plugins or /usr/lib64/nagios/plugins
Debian                 | nagios-plugins     | /usr/lib/nagios/plugins
FreeBSD                | nagios-plugins     | /usr/local/libexec/nagios
OS X (MacPorts)        | nagios-plugins     | /opt/local/libexec

Depending on which directory your plugins are installed into you may need to
update the `plugindir` macro in your Icinga 2 configuration. This macro is used
by the service templates contained in the Icinga Template Library to determine
where to find the plugin binaries.
Alternatively you can create a symbolic link pointing to the installation path
of the plugins.

### <a id="integrate-additional-plugins"></a> Integrate Additional Plugins

You may require a custom check plugin not provided by the official Nagios plugins.
All existing Nagios or Icinga 1.x plugins found on public community websites
will work with Icinga 2 as well.

* [MonitoringExchange](https://www.monitoringexchange.org)
* [Icinga Wiki](https://wiki.icinga.org)

Once you have downloaded the plugin copy it into the directory defined by the global
`IcingaMacro` `$plugindir$` and make sure that the user the Icinga daemon is running as
can execute the the plugin binary. Plugins should support the `--help` parameter
providing details how they have to be called in your command definition later on.

    # cp check_snmp_int.pl /usr/local/icinga/libexec/
    # chmod +x /usr/local/icinga/libexec/check_snmp_int.pl
    
    # /usr/local/icinga/libexec/check_snmp_int.pl --help
    
> **Note**
>
> You may require additional libraries for scripts. Please consult the installation
> documentation and/or README for their installation requirements.