Three-node Proxmox cluster

What I built

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Three refurbished mini PCs running Proxmox VE as a single cluster, which is where every lab VM and every deliberately-broken Windows domain now lives.

Why

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The constraint was noise, not budget. The lab lives in the same room I work in, so anything with 40mm server fans was disqualified before price entered the conversation. Mini PCs idle nearly silent and pull little enough power that leaving the cluster on permanently is not an argument with anyone.

Build

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Add photos by dropping them into this folder and referencing them relatively:

content/homelab/proxmox-cluster/
├── index.md
├── cover.jpg      <- becomes the card thumbnail automatically
└── rack.jpg

What broke

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Quorum. A three-node cluster tolerates exactly one node failing, and I learned what happens when you reboot two at once for updates: the survivor refuses to start anything, correctly, because it cannot prove it is not the minority side of a split. Obvious in hindsight, invisible at the time.

What I would do differently

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Separate the cluster’s own traffic from everything else from day one, rather than retrofitting it once the storage replication started interfering with the VMs it was supposed to be protecting.