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GMC Server Operations Runbook

Overview

The GMC (Gateway Management Controller) server handles WireGuard connections from XE300 IoT gateways. It runs on VM 2912 in the UK homelab and is accessed via hub2's UDP relay.

Architecture

XE300 Gateway (Internet)
        │
        ▼ UDP 39015
hub2 (51.68.235.106)
        │
        ▼ socat relay (gmc-relay container)
WireGuard VPN (wg-uk)
        │
        ▼
GMC Server (REDACTED_IP:39015)
    VM 2912 on px1-silverstone

Quick Reference

Component Location Value
Public endpoint hub2 51.68.235.106:39015/udp
Relay container hub2 charliehub_gmc_relay
GMC server px1 VM 2912 (REDACTED_IP)
WireGuard interface hub2 wg-uk

Verification Commands

On hub2

# Check relay is running
docker ps | grep gmc-relay

# Check relay logs
docker logs charliehub_gmc_relay

# Check port is listening
sudo ss -ulnp | grep 39015

# Check WireGuard connectivity
ping REDACTED_IP

# Watch incoming traffic
sudo tcpdump -i any udp port 39015 -c 10

On GMC Server (VM 2912)

# SSH to GMC server
ssh root@REDACTED_IP

# Check WireGuard service
sudo wg show

# Check GMC application status
systemctl status gmc  # or equivalent

Common Operations

Restart the relay

cd /opt/charliehub && docker compose restart gmc-relay

Update GMC IP

If GMC server moves to a new IP:

# 1. Edit .env
nano /opt/charliehub/.env
# Update: GMC_IP=<new_ip>

# 2. Restart relay
cd /opt/charliehub && docker compose restart gmc-relay

# 3. Verify connectivity
ping <new_ip>
docker logs charliehub_gmc_relay

Troubleshooting

XE300 not connecting

  1. Check relay is running: 

    docker ps | grep gmc-relay

  2. Check WireGuard connectivity: 

    ping REDACTED_IP
sudo wg show wg-uk

  3. Check GMC service is listening: 

    nc -uvz REDACTED_IP 39015

  4. Check UFW allows UDP 39015: 

    sudo ufw status | grep 39015

Relay not starting

# Check logs for errors
docker logs charliehub_gmc_relay

# Verify environment variables
grep GMC /opt/charliehub/.env

# Expected:
# GMC_IP=REDACTED_IP
# GMC_PORT=39015

WireGuard tunnel down

# Check WireGuard status
sudo wg show wg-uk

# If no recent handshake, check:
# 1. UCG is online
# 2. WireGuard config hasn't changed
# 3. Network connectivity to UK site

# Restart WireGuard
sudo systemctl restart systemd-networkd