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Homelab· 1 min read
Setting up a Proxmox cluster
Three nodes, one bad cable, and a lesson in quorum.
Overview
Building a three-node Proxmox VE cluster teaches you more about distributed systems than any textbook. This is the story of how one faulty ethernet cable brought down the entire cluster — and what quorum really means in practice.
What I built
- 3× mini-PCs running Proxmox VE 8.x
- Corosync for cluster communication
- Shared storage via NFS from a TrueNAS instance
The lesson
Quorum requires a majority of nodes to agree before making changes. With 3 nodes, losing 2 splits the cluster and halts all VM operations. A bad cable between node-2 and node-3 looked like a network partition to Corosync — and the cluster froze.
The fix: replace the cable, check pvecm status, rejoin the partition.