Check_MK and OMD
December 21. 2014
OMD - The Open Monitoring Distribution
OMD - The Open Monitoring Distribution - is a successful project started in 2010 by Mathias Kettner. It is a distribution of several monitoring cores (Nagios, Icinga, Shinken) and addons the makes open source monitoring a lot easier while at the same time keeping all the flexibility that friends of Nagios & Co are used to.
OMD ist not a Linux distribution but just ships the components of the actual monitoring software. It comes as one single package. The official project homepage is omdistro.org. We also offer a subscription to a download of pre-built packages of OMD for more than a dozend Linux distributions bundled with all available Check_MK versions.
Check_MK is part of OMD. This article describes some of the specialities when using Check_MK within OMD.
Directories and files: what is where?
While manual installations of Check_MK have individual settings of all relevant directories and file paths, OMD uses non-configurable standardized paths. If you are new to OMD you might think that this is a drawback. But soon you will realize the advantages of this approach. One of them is that paths used in this article are valid for all OMD installations 'round the world.
Since we have one variable component in all paths - the name of your site - we will assume that:
Paths used by Check_MK within OMD
One main difference of using Check_MK in OMD as opposed to a manual installation is the availability of the local hierarchy. It is a directory structure within each site that is used for (your) local extensions of Check_MK. You can install your own checks, Multisite-Plugins and other things directly into a site without modifying OMD and without root permissions. You can even override static files (images, stylesheets) for the web application by simply putting them into the correct directory.
Directories below ~/local/share/check_mk:
Using MKPs in OMD
Check_MK has its own packager for managing extensions (like collections of own checks). Check_MK packages are calles MKPs and are easy to create and install. When you install an MKP within an OMD site then the file will automatically be put into the local structure of the site. You do not need root-permissions for installing MKPs. Please note, that MKPs are always local to one site.