3rd Ceph MON on external QDevice (Podman) - 4-node / 2-site cluster

[paname]

Hi everyone,


I’m setting up a 4-node Proxmox cluster split across two datarooms (2 nodes per site).
Each site runs its own Ceph MON, and I have a Debian QDevice (for Proxmox quorum) hosted outside both sites.


I’m planning to run a 3rd Ceph MON on this QDevice using Podman, so that I have 3 MONs total for proper Ceph quorum.
This would give me:

- Site 1 → MON #1
- Site 2 → MON #2
- QDevice (external) → MON #3 (in Podman)

Goal: maintain both Proxmox HA quorum (via QDevice) and Ceph quorum even if one site goes down.
This setup is based on this article

Is this topology reliable and supported, having the 3rd Ceph MON running externally on a QDevice host (Podman)?
Any known issues with quorum or latency when the MON is not on a Proxmox node?

 

[paname]

bump

 

[aaron]

For stretch PVE + Ceph clusters we recommend a full PVE install for the tie-breaker node. See the newly published guide: https://pve.proxmox.com/wiki/Stretch_Cluster

 

[paname]

For stretch PVE + Ceph clusters we recommend a full PVE install for the tie-breaker node. See the newly published guide: https://pve.proxmox.com/wiki/Stretch_Cluster

Hi, thanks for the answer. Do you think my solution works, or do I strictly need to do the 'tie-breaker' steps?

 

[paname]

bump

 

[aaron]

Hi, thanks for the answer. Do you think my solution works, or do I strictly need to do the 'tie-breaker' steps?

maybe, never tried it. it is definitely more complex and chances are that things go out of sync in the ceph config if you are not careful. or versions might differ a bit between the ceph mons.
if things go wrong and you run a unique setup like that, you will be more on your own as not many people will have any experience doing it that way