Cluster/Ha upgrading: version differences

[iccbroadcast]

Hi forum.

I'm planning an eventual upgrade of my PROXMOX 5-node cluster.
The cluster is 6.2-15, so far so good.. pretty stable.

The thing is, from my experience, I don't like to let the cluster getting 'too old' (unexpected problems when the time comes to join a new node or replacing one).
The difference now (from my other clusters) is that, since 6.x , I'm using HA (with good results, I'm very happy with that) ... but the documentation states that, all nodes in cluster must be 'same version'... so now I got several questions blowing my head:

- Does that refer to some major versioning? ( 6.x vs 6.y) , or does it refer to exactly and precisely the same version (6.x-a vs 6.x-b)?
- What happens as the first node on the cluster updates (thus, breaking the 'all the same version rule')? ... disaster?
- What is the ideal procedure for a cluster upgrade? (my guess is the classic rolling upgrade..but that 'all the same version' is very scary)

Thank you very much.

Best regards.

 

[iccbroadcast]

Has anyone tried to upgrade a node in a cluster with HA? what happens when the first node has mismatched version?

Regards.

 

[dcsapak]

hi,
sorry for the late answer

i guess you reference this sentence:

If you are interested in High Availability, you need to have at least three nodes for reliable quorum. All nodes should have the same version

from https://pve.proxmox.com/wiki/Cluster_Manager

in general, mixed versions during an upgrade are ok, expected and tested.
what is not tested (and here there are no guarantees) is running a cluster
with very different versions for a prolonged amount of time.

the usual procedure for cluster upgrades would be something like

* migrate/move all (running) vms/containers away from a node
* upgrade the node (reboot if there was a kernel upgrade)
* migrate the machines back

and that for every node until the versions are the same again

for major upgrades there are sometimes some extra steps for clusters/ha, but this should be contained in our guides (e.g for 5.x to 6.0: https://pve.proxmox.com/wiki/Upgrade_from_5.x_to_6.0 )

i would also recommend having working/tested backups, and even a test-system where you could test such upgrades