## <a id="running-icinga2"></a> Running Icinga 2

### <a id="init-script"></a> Init Script

Icinga 2's init script is installed in `/etc/init.d/icinga2` by default:

    # /etc/init.d/icinga2
    Usage: /etc/init.d/icinga2 {start|stop|restart|reload|checkconfig|status}

  Command             | Description
  --------------------|------------------------
  start               | The `start` action starts the Icinga 2 daemon.
  stop                | The `stop` action stops the Icinga 2 daemon.
  restart             | The `restart` action is a shortcut for running the `stop` action followed by `start`.
  reload              | The `reload` action sends the `HUP` signal to Icinga 2 which causes it to restart. Unlike the `restart` action `reload` does not wait until Icinga 2 has restarted.
  checkconfig         | The `checkconfig` action checks if the `/etc/icinga2/icinga2.conf` configuration file contains any errors.
  status              | The `status` action checks if Icinga 2 is running.

By default the Icinga 2 daemon is running as `icinga` user and group
using the init script. Using Debian packages the user and group are set to `nagios`
for historical reasons.

### <a id="cmdline"></a> Command-line Options

    $ icinga2 --help
    icinga2 - The Icinga 2 network monitoring daemon.

    Supported options:
      --help                show this help message
      -V [ --version ]      show version information
      -l [ --library ] arg  load a library
      -I [ --include ] arg  add include search directory
      -D [ --define] args   define a constant
      -c [ --config ] arg   parse a configuration file
      -C [ --validate ]     exit after validating the configuration
      -Z [ --no-validate ]  skip validating the configuration
      -x [ --debug ]        enable debugging
      -d [ --daemonize ]    detach from the controlling terminal
      -e [ --errorlog ] arg log fatal errors to the specified log file (only works
                            in combination with --daemonize)
      -u [ --user ] arg     user to run Icinga as
      -g [ --group ] arg    group to run Icinga as

    Report bugs at <https://dev.icinga.org/>
    Icinga home page: <http://www.icinga.org/>

#### Libraries

Instead of loading libraries using the [`library` config directive](#library)
you can also use the `--library` command-line option.

#### Constants

[Global constants](#global-constants) can be set using the `--define` command-line option.

#### Config Include Path

When including files you can specify that the include search path should be
checked. You can do this by putting your configuration file name in angle
brackets like this:

    include <test.conf>

This would cause Icinga 2 to search its include path for the configuration file
`test.conf`. By default the installation path for the Icinga Template Library
is the only search directory.

Using the `--include` command-line option additional search directories can be
added.

#### Config Files

Using the `--config` option you can specify one or more configuration files.
Config files are processed in the order they're specified on the command-line.

#### Config Validation

The `--validate` option can be used to check if your configuration files
contain errors. If any errors are found the exit status is 1, otherwise 0
is returned.

### <a id="features"></a> Enabling/Disabling Features

Icinga 2 provides configuration files for some commonly used features. These
are installed in the `/etc/icinga2/features-available` directory and can be
enabled and disabled using the `icinga2-enable-feature` and `icinga2-disable-feature` tools,
respectively.

The `icinga2-enable-feature` tool creates symlinks in the `/etc/icinga2/features-enabled`
directory which is included by default in the example configuration file.

You can view a list of available feature configuration files:

    # icinga2-enable-feature
    Syntax: icinga2-enable-feature <feature>
    Enables the specified feature.

    Available features: statusdata

Using the `icinga2-enable-feature` command you can enable features:

    # icinga2-enable-feature statusdata
    Module 'statusdata' was enabled.
    Make sure to restart Icinga 2 for these changes to take effect.

You can disable features using the `icinga2-disable-feature` command:

    # icinga2-disable-feature statusdata
    Module 'statusdata' was disabled.
    Make sure to restart Icinga 2 for these changes to take effect.

The `icinga2-enable-feature` and `icinga2-disable-feature` commands do not
restart Icinga 2. You will need to restart Icinga 2 using the init script
after enabling or disabling features.