So yeah, today I was upgrading my Proxmox from v7 to v8.

Due to the recommendations in their wiki I decided against doing a live upgrade and instead went with reinstalling the new version.

So… What do I do with the existing machines in the meantime? I could just do a backup and restore… But I wanted to try out the cluster thing. Reasoning was “if something goes wrong, I still need my DNS server” (which runs in a Proxmox container). With the cluster feature, I can move the VMs / containers to a different PC.

So, I first set up a VM on my Linux PC (with libvirt / KVM / QEMU), installed Proxmox there, created a cluster from my current “main Proxmox”, and joined the new machine. All via the web interface, which went very neat.

After I migrated the containers over, I shut down my “main Proxmox” and wanted to remove it from the cluster (to avoid problems when re-adding it later). So I followed the Wiki, ssh’ed to my now “backup Proxmox”, happily wanted to execute pvecm delnode srv-proxmox with the result of … cluster not ready - no quorum?. Huh? Wait, what?

Well, turns out, Proxmox by default seems to assume enterprise setups, and no enterprise has just two machines ;-). No, I didn’t read about the specifics, but apparently you need at least two online machines at any given time when you have a cluster. I looked it up, after executing pvecm expected 1 I was able to remove the soon-to-be-upgraded machine from the cluster.

So, the installation itself went smooth. After the installation, I joined my “main Proxmox” back into the cluster, ssh’ed into it, executed a pvecm updatecerts as mentioned in the Wiki.

Currently, I still have a cluster, although I may as well dissolve it, have to look up how. The second machine in a VM will go. I have no need for it anymore… until the next upgrade.