I stumbled across a neat utility that was introduced in RHEL 7.5. It integrates LVM snapshots with Grub for a similar rollback functionality as we see in SUSE. In theory giving a safety net during major changes, updates, etc.
Does anyone have feedback on this tool? And has anyone tested on RHEL 8 or 9?
https://www.redhat.com/en/blog/boom-booting-rhel-lvm-snapshots
Thanks for any feedback!
Posted Dec 11, 2022, 6:01 AM UTC
I currently use LVM snapshots for this, though I don't boot the snapshots themselves. It works extremely well in my experience, no issues to date.
Instead I make the snapshot during early boot using a systemd target (using grubby and grub2-reboot to create then boot an entry with the create_snapshot target as a var.) Then I run the risky updates normally, and if they don't work I merge the snapshot and reboot. I got this process from the Arch wiki.
Looks like boom exists to make booting from the snapshot easier so that you can test on it, rather than the other way around? I might give it a shot, I could see that seeming lower risk. LVM snapshots seem reliable enough to me though that I'm not sure it's necessary.
That's helpful. Thanks for this practical alternative too!
Boom boot is a super useful tool for when you are:
Not the admin of the Virt infra and can't have the infra do a snapshot
Working with metal/non Virt assets
I've used this myself extensively when working with metal and prototyping an RHOSP single role deployment. If the build fails you just record the error then snap back to a predeploy state, make your template fixes then try again. This approach reduces your RTO to a reboot, which is stellar.
That's great to hear. I have a few bare metal use cases that could definitely benefit from a quick rollback option like this and accessible right from grub.
Do you have an experience using it on RHEL 8 or 9?
RHEL 8.4 with RHOSP 16.2
Haven't tried rhosp17 yet, but I expect it will be similar
Awesome - thank you for the feedback!
I was exciting to learn about Boom, but it is useless to most of us as I am pretty sure most would move /var to its own logical volume (some do this with /usr as well)...Boom does not support that today... 8-(
I used to do this manually ( without grub ) so it is nice to see a improved, unified solution. Never heard about this or saw a publication so thanks !
You bet! Yeah seems like something that would be great to script into update processes.