Upgrading check-mk and Debian

1. Overview

Upgrading Debian from 8 (jessie) to 9 (stretch) with check-mk installed isn’t as easy as it seems. You have to:

  1. Upgrade check-mk to 1.4.0 and fix all issues
  2. Backup all sites
  3. Purge check-mk
  4. Upgrade debian
  5. Reinstall check-mk 1.4.0
  6. Restore the check-mk-sites from backup

2. Upgrade check-mk and back it up

Download the .deb package and install it. Follow the official the official guide and upgrade all sites. After fixing all issues, create a backup of each site:

# su - <sitename>
$ omd backup site.name.tar.gz

Repeat this for all sites.

3. Remove check-mk and upgrade to stretch

Stop sites:

# su - <sitename>
$ omd stop

Repeat this for all sites. Then remove (purge) check-mk:

# dpkg -P check-mk-raw-1.4.0p17

Once this is done, update the distribution to debian (you really should know how to do that!). Autoremove all obsolete packages and reboot.

4. Reinstall check-mk and restore from backup

Download the .deb package for stretch and install it. Since you autoremoved dependent packages earlier, the install will most likely fail. Fix it with:

# apt --fix-broken install

Now we can restore the sites from our backup (as root!):

# omd restore <site-name.tar.gz>
# su - sitename
$ omd start

Repeat for all sites and fix all remaining issues.

5. Notes

Of course you don’t want to do this without a security net. Take a snapshot and destroy that instead of the real VM. How to do that with KVM and libvirt is explained here.