Due to the strict separation of software and data, it is also possible to install several versions of OMD in parallel, in addition to operating several sites on one server. In doing so, OMD determines for each site which of the installed versions it will use.
This is made possible by the way OMD carries out an update. You do not have to update the complete Open Monitoring Distribution at once, rather only one site at a time. This gives you the choice of which of the sites you want to update to the new version and which not.
After installing the new OMD version via an RPM or DEB package, the desired site can be updated to the new version with the
omd update command. Afterwards, the old OMD version can be uninstalled if it is no longer needed.
The copy function with the
omd cp command also offers an additional, convenient way to carry out the update.
This makes it possible, for example, to copy the production site and then update the copy. By doing so, you have the possibility to extensively test the new version with the copied site and to clean up any possible problems before updating the production site.
Furthermore, in the past it was possible to downgrade a site, i.e. to go back to an older version. The process works analogously to the update, since the omd update command does not care whether the target version is newer or older than the current version. Since Checkmk 1.6, however, a downgrade is no longer supported.