Proxmox Cluster / different version compatibility

[lady_in_red2000]

Hello,
So the client have quite old Proxmox cluster with 18 servers in this cluster. These servers running "Virtual Environment 5.4-15". Yes. That old versions of Proxmox.
I'm pushing customer to upgrade to the latest version, but it's a long story.

Currently they buying a new server.
My question is about compatibility. Will the cluster work and accept a new member (server), if i will install latest 8.1v on the new server, while rest of the servers will run old 5.4v.

Will i have any issues with that? If yes, what would be the right way to made upgrade? There are plenty of VM's running. a huge web portal, and there is no way to turn everything down. I can migrate VM's between servers, and only can upgrade (if needed) one server at the time.

Thank you,

 

[ubu]

No, this will NOT work 7 and 8 together work, but 5 is before knet.

You will have to upgrade your cluster from 5 to 6, then from 6 to 7 and from 7 to 8. Have fun

 

[lady_in_red2000]

OMG. So there is no way to upgrade from v5 to v8 without going over 6 and 7 ?

 

[ubu]

Yes, or you install a new cluster and migrate your vms

 

[lady_in_red2000]

Yes, or you install a new cluster and migrate your vms

This sounds easier. Will VM work if i migrate them from v5 to v8?
Should i do that by backing up on v5 and restoring on v8? As it will be different clusters probably there is no way to migrate them directly?

Thank you.

 

[ubu]

VMs should work without any problems, very old systems in containers might have problems with cgroup v2

 

[Dunuin]

As it will be different clusters probably there is no way to migrate them directly?

Meanwhile there is cross-cluster-migration in tech preview but won't help you with your ancient cluster

 

[Dunuin]

So yes. Backup + restore to new cluster or doing the long upgrade from 5->6->7->8.

 

[lady_in_red2000]

Great. Thank. you for your help!