Linstor and Proxmox update completed successfully

Following a migration from Ceph to Linstor in my small 3-node cluster, I hadn't updated Proxmox or Linstor until today, as everything was working perfectly and without any glitches. However, on a warm Friday evening, I finally decided to do the update... Here is a short update plan I came up with—maybe someone will find it useful:

To update Linstor and DRBD in a 3-node cluster, follow these steps:

1. Check the Linstor cluster status: run linstor node list. You should see ONLINE for all nodes.
2. Check current versions: run cat /proc/drbd for DRBD and linstor -v for Linstor. Take note of them.
3. Check storage pool health: run linstor storage-pool list. The state must be OK. If it isn't, fix it before moving forward.
4. Update Linstor on ALL nodes: run apt install -y --only-upgrade linstor*. Note that while running this command, step 1 might show a MISMATCH_ status. Once all nodes are updated, the status should return to ONLINE.
5. Migrate and update DRBD: Migrate all VMs away from the node you are about to update, then run apt install -y --only-upgrade drbd*. The kernel module patch should compile, but the version won't change just yet.
6. Update Proxmox: run apt update && apt upgrade -y. Reboot the node.
7. Verify: Log back in and check the versions, node statuses, and pool states.

P.S. Since I have DRBD-Reactor installed and a separate storage pool for the controller database, there's no need to stop any services manually. The controller migrates automatically during updates and reboots. (Note: If you don't use DRBD-Reactor, you would need to manually stop linstor-satellite.service and linstor-controller.service on the nodes before updating).

P.P.S. I shut down all VMs during the update except for my OPNsense firewall, but honestly, you don't really have to do that—I didn't notice any disruptions or glitches with the running VMs.