My last two posts, Starting NRPE via launchd and Nagios NRPE on OS X Server 10.5, concerned getting NRPE to run on OS X Server 10.5 and having it startup at system boot.
However, this is only part of the battle. Once you have Nagios monitoring setup on your server you also need to have some nice options for checking the availability of your running services.
Tim Wilson from the Savvy Technologist, wrote an NRPE plugin that helps out with this. The plugin check_osx_services does an excellent job of checking on the status for many services running on 10.5 Server.
The documentation on the plugin at the NagiosExchange site is pretty thorough. One thing that is not mentioned is that you will need to run the check_osx_services script as superuser since it calls the system level command serveradmin which must be run as root.