Back Matter
Troubleshooting Index
| Symptom | Likely Cause | Fix |
|---|---|---|
| SSH to Spark 2 times out | iptables blocked after k3s restart | Flush iptables — see Ch 2 |
| DNS not resolving | systemd-resolved cache stale | sudo resolvectl flush-caches |
| GPU not visible in k8s | GPU Operator pods not Running | Check kubectl get pods -n gpu-operator |
| Ray shows GPU: 1 not 2 | Worker pod not connected | Check worker logs; verify DNS address |
| "exec format error" | x86 image on ARM64 | Use nvcr.io/nvidia/vllm:25.09-py3 |
| Model download fails | HF token missing/invalid | Check kubectl get secret hf-token -n core-services |
| AIBrix CrashLoopBackOff | Dependencies not installed first | Apply aibrix-dependency before aibrix-core |
| NGC image pull fails | containerd lacks NGC credentials | Create docker-registry Kubernetes secret — see Ch 5 |