check_omd

check_omd is a Nagios / Icinga plugin for checking a particular OMD site's services.

Requirements

I successfully tested the plugin with OMD site versions 1.20 to 2.70. As the plugin needs to be executed by the site user, a sudo rule is needed. A template (check_omd-sudo-template) is part of the repository.

Usage

By default, the script checks all services of the site - it is also possible to exclude services if they are predicted to fail in your environment (-x / --exclude parameters).

The following parameters can be specified:

Parameter	Description
-d / --debug	enable debugging outputs (default: no)
-h / --help	shows help and quits
-w / --warning	defines one or more services that only should throw a warning if not running (useful for fragile stuff like npcd)
-x / --exclude	excludes a particular service from the check
-H / --heal	automatically restarts the services that are not running
-t / --timeout	after how many seconds a process should run into a timeout
--version	prints programm version and quits

Examples

The following example indicates an running OMD site:

$ ./check_omd.py
OK: OMD site 'stankowic' services are running.

A site with a failed nagios service:

$ ./check_omd.py
CRITICAL: OMD site 'hansel' has failed service(s): 'nagios'

OMD site giertz with a well-known daemon, that's crashing sometimes:

$ ./check_omd.py -x npcd
OK: OMD site 'giertz' services are running.

OMD site clpmchn, excluding npcd from throwing critical states:

$ ./check_omd.py -w npcd
WARNING: OMD site 'clpmchn' has service(s) in warning state: 'npcd'

Installation

To install the plugin, move the Python script, the agent configuration and sudo rule into their appropriate directories. The paths may vary, depending on your Linux distribution and architecture. For RPM-based distribtions, proceed with the following steps:

# mv check_omd.py /usr/lib64/nagios/plugins
# mv check_omd-sudo-template /etc/sudoers.d/
# chmod +x /usr/lib64/nagios/plugins/check_omd.py
# chmod 0440 /etc/sudoers.d/check_omd-sudo-template

When using NRPE, copy the appropriate configuration and restart the daemon:

# mv check_omd.cfg /etc/nrpe.d/
# service nrpe restart

When using Icinga2, copy the configuration to ITL (Icinga Template Library), e.g.:

# cp check_omd.conf /usr/share/icinga2/include/plugins-contrib.d/
# service icinga2 restart

Make sure to alter the sudo configuration to match your OMD site name, e.g.:

nrpe ALL = (stankowic) NOPASSWD: /usr/lib64/nagios/plugins/check_omd.py

It also possible to create a RPM file for your Linux distribution with the RPM spec file:

$ rpmbuild -ba nagios-plugins-check_omd.spec
...

The RPM spec has been tested on Enterprise Linux 5 to 7, i386 and x86_64. Currently, the RPM package only includes NRPE-related configuration, Icinga2 will follow.

Configuration

Nagios / Icinga 1.x

Inside Nagios / Icinga you will need to configure a remote check command, e.g. for NRPE:

#check_nrpe_omd
define command{
    command_name        check_nrpe_omd
    command_line        $USER1$/check_nrpe -H $HOSTADDRESS$ -c check_omd -a $ARG1$
}

Configure the check for a particular host, e.g.:

#SRV: omd stankowic
define service{
        use                             generic-service
        host_name                       st-mon02
        service_description             SRV: omd stankowic
        check_command                   check_nrpe_omd!stankowic
}

Icinga2

Define a service like this:

apply Service for (SITE => config in host.vars.omd_sites) {
  import "generic-service"
  check_command = "check_omd"
  if (host.name != NodeName) {
    command_endpoint = host.name
  }
  vars += config
  assign where host.vars.app == "omd"
  ignore where host.vars.noagent
}

Create omd_site dictionaries for your hosts and assign the app variable:

object Host "st-mon04.stankowic.loc" {
  import "linux-host"
  ...
  vars.app = "omd"
  ...
  vars.omd_sites["PROC: OMD pinkepank"] = {
    omd_site = "pinkepank"
  }
  vars.omd_sites["PROC: OMD giertz"] = {
    omd_site = "giertz"
  }

Validate the configuration and reload the Icinga2 daemon:

# icinga2 daemon -C
# service icinga2 reload

Troubleshooting

Plugin not executed as OMD site user

The plugin will not work if is not executed as site user:

$ whoami
taylor
$ ./check_omd.py
UNKNOWN: unable to check site: 'omd: no such site: taylor' - did you miss running this plugin as OMD site user?

An error message like this will be displayed if multiple OMD sites are available and you're running the plugin as root:

# ./check_omd.py
UNKOWN: unable to check site, it seems this plugin is executed as root (use OMD site context!)

Contributors

Thanks a lot for your support:

• lgmu