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2026/01/04 - qdevice

I have a 2 node cluster, it doesn't work without a qdevice.

Here is what should have been done to set that up.

  • On the qdevice VM
    apt update && apt install -y corosync-qnetd
    systemctl enable --now corosync-qnetd
  • On both pve1 and pve2
    apt update && apt install -y corosync-qdevice
  • pve1
    pvecm qdevice setup <qdevice-ip-or-hostname>

Here's what really happened:

  • Started with a 2-node Proxmox cluster:

  • pve1 online, pve2 powered off.

  • Proxmox UI/API threw 500 cluster not ready - no quorum.

  • 2-node clusters "lose quorum" when one node is down unless you add a third vote.

  • Decided to add a QDevice (qnetd) as the “third vote” instead of forcing quorum with pvecm expected 1.

  • Provisioned a new Debian 13 VM to act as the QDevice host:

  • Proxmox QDevice setup attempts began from pve1:

  • pvecm qdevice setup 192.168.0.233

  • ssh-copy-id warnings about keys already existing showed up repeatedly (I messed up)

  • First major blocker: missing tools / inconsistent state across nodes:

  • One setup attempt failed because corosync-qdevice-net-certutil was missing.

  • Installed corosync-qdevice on both pve1 and pve2.

  • Verified tool exists with:

    • which corosync-qdevice-net-certutil

  • Messages like “Certificate database already exists” and certificate-store reuse problems.

  • Tried cleaning /etc/corosync/qnetd and starting over.

  • qnetd failed with:

    • Can't open NSS DB directory (2): No such file or directory

    • After recreating, it failed with:

    • Can't open NSS DB directory (13): Permission denied

  • Switched to an “investigate first” approach (Basically, asked ChatGPT for a block of read only commands to help troubleshoot, when it gives you commands to delete anything don't do it, gathering information and giving it that works much better):

  • Ran the final successful setup:

  • pvecm qdevice setup 192.168.0.233 --force

  • pvecm status showed:

    • Config Version: 3
    • Expected votes: 3
    • Total votes: 3
    • Flags: Quorate Qdevice
    • Membership included a Qdevice voter

  • Cluster now has a tie-breaker vote and no longer dies on quorum when one node goes down.