Proxmox Cluster with different versions & upgrading


Active Member
Jun 6, 2017

This post is in two parts.

Currently have a cluster of 4 physical servers running proxmox 4.4-15. I want to add a 5th server to the cluster but running 5.4. Before I do this do they play nicely together? Is this scenario supported and even possible?

Part two of the question.

I want to slowly over a period of weeks upgrade each server from 4.4 to 5.4 by doing apt-get dist-upgrades. Is this ok, is there a more preferred way to do it? Any gotchas to know about? Especially thinking about the cluster setup. Can I do this whilst the server is still in the cluster?

Many thanks
Running mixed PM versions is in a single cluster is officially discouraged.
From my personal experience, this can not be a real problem, but only if you never migrate VMs from newer to older version and are aware of what features are available on what nodes.

I would suggest you install latest and gratest using no subs repo, then migrate all VMs from one node to this new node. Then upgrade the empty node and so forth untill you have all nodes up to date.

I would also suggest you do a quick browse on the forums for topics such:

Me personally, I would just do a clean install of old 4.4 nodes not just replacing apt sources list and upgrading. Please note that in this case, you must first destroy an old 4.4 node and then remove it from cluster, never to be running on the same network before reinstall.
I was hoping to upgrade the physical servers in place.

I was thinking of the following
  • Stop all VMs on that hypervisor
  • Take a backup, before starting.
  • Do in place upgrade from 4.4-15 to 5.4
  • Reboot hypervisor
  • Pray the cluster is still working
  • Power up the VMs again.

  • Repeat the exercise each week to upgrade all 4 servers over 4 weeks.
Do you think this will be ok?

I appreciate what your saying about moving the VMs to another hypervisor, and doing a clean install of 5.4 (removing from the cluster first) on each one, but this isn't practical in this current setup. It would appear the 4 proxmox servers were merely joined in a cluster so the old administrator only had one web portal to manage the lots, instead of true clustering. Each Hypervisor seems to have a select number of VMs and no movement on the cluster (certainly not with the size of some of those vDisks).
When you backup, do an external backup, somewhere outside from the node you will upgrade and reboot and your data will be safe.
Good luck!


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