Werk #12850: Migrating Checkmk configurations during site renamings

Komponente Core & Setup
Titel Migrating Checkmk configurations during site renamings
Datum 04.08.2021
Checkmk-Editon Checkmk Raw (CRE)
Checkmk-Version 2.1.0i1
Level Bedeutende Änderung
Klasse Neues Feature
Kompatibilität Kompatibel - benötigt kein manuelles Eingreifen

Users which execute omd mv or omd cp expect Checkmk to not only rename the site, but also migrate the Checkmk configuration in a way that they can continue seamlessly with their existing Checkmk configuration.

This feature did not exist before and was a common misunderstanding. The commands listed above did not take care of the Checkmk configuration files. In fact the site management, which is realizing the renaming of a site, does not know anything about the Checkmk configuration files.

However, with this change we create the integration of both worlds. In the moment a site renaming or copy is performed, the site management informs Checkmk about this action and gives it the chance to update it's configuration files.

The most important parts of the Checkmk configuration are now updated:

  • Distributed monitoring (sites) configuration
  • Host & folder site attributes
  • Dynamic host configuration site attribute

The new logic is also trying to detect specific situations and displays warnings about things that can (currently) not be migrated automatically.

For example, if the renaming of a distributed remote site is detected, a warning is now displayed that you also have to update the distributed monitoring configuration in the central site of your setup.

Details:

OMD, which is responsible for providing the site management of Checkmk, itself is only caring about migrating the files and file parts that are initially installed when creating a new Checkmk site. Clearer: If you create a clean site and then execute grep -r $OMD_SITE etc in your site, you can see a lot of files which contain the ID of the site. These things are already migrated by OMD.

But OMD is not aware of the configuration files of the applications shipped with OMD. For example the Checkmk configuration files are not understood by OMD. And that's totally fine from an architectural point of view, because OMD is an separate component that manages installation of different applications, but must not mess with their individual files.

However, from a users perspective it's clear that you also want the application files to be migrated during site renaming.

This change introduces the general mechanism:

  • OMD detects changes of the site ID (mv, cp or restore)
  • Then it executes the command post-rename-site -v -o [OLD_SITE_ID]
  • The command post-rename-site then takes care of the Checkmk configuration updates
  • It can also detect some situations it can not solve on it's own and warns the user about potential manual steps to do afterwards.

The migration steps are realized in so called rename action plugins which can easily be extended. In the git you can find them at cmk/post_rename_site/plugins/actions.

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