Wiping and resetting your SUSE OpenStack Cloud Crowbar configuration

Posted on Tue 05 July 2016 in hints-and-kinks • 2 min read

Note: This article was originally written for SUSE OpenStack Cloud 6, and updated for SUSE OpenStack Cloud 7. It may not apply to later SUSE OpenStack Cloud releases.

If you’re using SUSE OpenStack Cloud, you may want to erase and reinstall your cloud deployment a few times during the testing or proof-of-concept phase. You may also want to experiment with a few permutations of Crowbar network configurations. SUSE’s (otherwise excellent) Deployment Guide suggests that the only way to change your Crowbar settings, after install-suse-cloud has been run, is to reinstall your entire admin node. That isn’t really true if you know what you’re doing.

You may be thinking that you could just use snapper to revert to your last Btrfs snapshot created before you ran install-suse-cloud. After all, running yast2 crowbar, like any other YaST module, automatically creates a before-and-after Btrfs snapshot of your root filesystem and all its subvolumes. So, reboot machine, select pre-install-suse-cloud snapshot, complete boot, run snapper rollback, done. Right?

Well, not quite. If you followed the Deployment Guide closely, you will have removed your Btrfs subvolume for the /srv directory, and replaced it with a separate, XFS-formatted partition. That means it is excluded from all snapper Btrfs snapshots, and thus, no rollback for you for that directory. Which, of course, Crowbar uses rather extensively.

So, here is your checklist for resetting your admin node to a pre-install-suse-cloud state:

  • Reboot your admin node.

  • In the SLES boot menu, select an appropriate snapshot taken immediately prior to running install-suse-cloud.

  • Boot into your snapshot.

  • Run snapper rollback.

  • Reboot again.

  • After rebooting, delete the following and directories:

    • /srv/tftpboot/authorized_keys
    • /srv/tftpboot/validation.pem
    • all subdirectories under /srv/tftpboot/nodes/

Then, you can reconfigure Crowbar (yast2 crowbar), run install-suse-cloud, and reboot your OpenStack nodes. They should be discovered anew, and you’re then able to redeploy your OpenStack barclamps to them.

This article originally appeared on the hastexo.com website (now defunct).