OpenClaw in a Mini Rack: AI-Powered Homelab Monitoring

The Mini Rack Craze

Jeff Geerling started a movement with his mini rack project, and I jumped on board. My 10-inch rack holds a Pi cluster, a NAS, networking gear, and now — an OpenClaw agent that watches everything.

My Rack Layout

┌─────────────────────────────────┐
│  1U  │ MikroTik 2.5G Switch     │
├──────┼──────────────────────────┤
│  1U  │ Pi 5 (OpenClaw Gateway)   │
├──────┼──────────────────────────┤
│  1U  │ Pi 5 (k3s control plane)  │
├──────┼──────────────────────────┤
│  1U  │ Pi 5 (k3s worker)         │
├──────┼──────────────────────────┤
│  2U  │ 4-bay NVMe NAS (Pi 5)     │
├──────┼──────────────────────────┤
│  1U  │ UPS + power strip         │
└──────┴──────────────────────────┘

What OpenClaw Monitors

Every 30 minutes (via heartbeat), OpenClaw checks:

# HEARTBEAT.md
- SSH into each Pi and check: CPU temp, disk usage, memory, uptime
- Query k3s: kubectl get nodes, check pod health
- Check NAS: ZFS pool status, disk temps, scrub schedule
- Check UPS: battery level, load percentage
- Check network: ping gateway, check DNS resolution

The Monitoring Script

OpenClaw runs these checks through SSH tool calls:

# Check all Pi temperatures
for host in pi-openclaw pi-k3s-1 pi-k3s-2 pi-nas; do
  temp=$(ssh $host "vcgencmd measure_temp" 2>/dev/null)
  echo "$host: $temp"
done

# Check ZFS pool health
ssh pi-nas "zpool status -x"

# Check k3s cluster
ssh pi-k3s-1 "kubectl get nodes -o wide"
ssh pi-k3s-1 "kubectl get pods -A | grep -v Running | grep -v Completed"

Alert Thresholds

OpenClaw doesn’t just dump data — it knows what’s important:

• CPU temp > 70°C → Warning: “pi-k3s-1 is running hot (72°C). Check ventilation.”
• Disk usage > 85% → Alert: “NAS pool is at 87%. Time to clean up or add storage.”
• Pod crashlooping → Alert: “grafana pod has restarted 5 times in the last hour.”
• UPS < 50% → Warning: “UPS battery at 45%. Power has been out for 12 minutes.”
• Everything normal → Silence (HEARTBEAT_OK)

Daily Summary

Once a day at 8 AM, OpenClaw sends a digest:

📊 Homelab Daily Report 🟢 All 4 nodes healthy (avg temp: 52°C) 🟢 k3s: 23 pods running, 0 issues 🟢 NAS: 2.1TB used / 4TB (52%), last scrub 3 days ago 🟢 UPS: 100%, 45W load 🟢 Network: 0 packet loss, 1ms gateway latency

Power Draw

The entire rack, including OpenClaw:

MikroTik switch:     8W
Pi 5 (OpenClaw):     5W
Pi 5 (k3s x2):      10W
Pi 5 (NAS):          7W
Total:               ~30W

Monthly cost: ~$3 electricity

A 30-watt homelab that monitors itself. Jeff would approve.