[SOLVED] Proxmox 5 node join a 4.4 Cluster

[krystofr]

Hi there,

I've read the documentation and wiki, and can see that a mixed cluster of Proxmox 3, and 4 is not permitted, but I couldn't find anything about proxmox 5.

Is it possible to add a proxmox 5 node to a proxmox 4.4 cluster or vice versa?

Thank you

 

[spirit]

yes, it's working without problem.

proxmox3-4 was not possible because of corosync 1 vs 2.

 

[krystofr]

Great - thank you for the prompt response

 

[fabian]

please be aware that this is not a recommended or well-tested setup. we generally try to ensure compatibility for upgrading from old to new (e.g., live-migration from 4.4 to 5.x should work, but in general, migrating from new to old possibly does not work), but that does not mean that 4.x nodes and 5.x nodes can work in one cluster regarding all features.

one example:
PVE 4.4 supports Ceph Jewel and Hammer using upstream Ceph packages from ceph.com
PVE 5.x supports Ceph Luminous using PVE-provided packages (currently still as technology preview)

there is an upgrade path via Luminous packages provided by ceph.com, but attempting to mix PVE 4.4 and PVE 5.x long-term in one cluster is a recipe for disaster in this scenario.

I strongly advise to either upgrade your cluster fully to 5.x (node by node, following the upgrade instructions) or stay on 4.4 until you are ready for the upgrade.

 

[krystofr]

thank you Fabian - good advise as always!

 

[chalan]

i just need to migrate from old proxmox 4 to new 5, is it safe?