Upgrading to Proxmox 6 by reinstalling servers

[macleod]

Hi
Generally speaking, I always prefer to reinstall than simply upgrading a server. Maybe it's more work to do but it's cleaner and "subtle differences" are avoided.
But, if I understood correctly, it's not possible to upgrade a pmx5 cluster this way (foreach pmx5, move vms, remove server from cluster, install pmx6, add server to cluster), even with corosync updated to v3. Why that ?
Also, even upgrading each server as-is, there will be a time window (days, weeks?) with mixed pmx5/6 servers. What is the worst that can happen ?
Thanks!

 

[oguz]

hi,

But, if I understood correctly, it's not possible to upgrade a pmx5 cluster this way (foreach pmx5, move vms, remove server from cluster, install pmx6, add server to cluster), even with corosync updated to v3. Why that ?

because our API around corosync ring addresses changed, so a pmx6 node won't be able to join a pmx5 cluster.

Also, even upgrading each server as-is, there will be a time window (days, weeks?) with mixed pmx5/6 servers. What is the worst that can happen ?

i suggest you keep this time window as small as possible. the correct way to do in-place upgrade[0], is to upgrade corosync on all nodes first, and then migrate your running guests to another node while upgrading the current node to pve6.

i suggest you to keep this time window relatively short, since there are API changes between pmx5 and pmx6 which could cause inconsistencies in the long run.

[0]: https://pve.proxmox.com/wiki/Upgrade_from_5.x_to_6.0#In-place_upgrade

 

[spirit]

To reinstall a server:

if your vm storage is not local,
you can backup /var/lib/pve-cluster/config.db ,
reinstall the host with same name/ip address, after boot, shutdown pve-cluster service , override config.db with your backup, reboot. Done.

I think it should work with backupking from 5, and restore on 6.


maybe upgrade corosync to version3 on all node first.