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

paname

New Member
Oct 29, 2025
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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?