pod-troubleshooting

# Skill: Pod Troubleshooting > **Expertise:** Systematic K8s failure diagnosis — from symptom to root cause in under 10 commands. ## When to load When a pod is not Running, a service is unreachable, or a deployment is stuck. ## Diagnostic Decision Tree ``` Pod not Running? ├── Status: Pending │ ├── No nodes match → check node selectors, taints, resource requests │ └── PVC not bound → check StorageClass, PV availability ├── Status: CrashLoopBackOff │ ├── Exit code 0 → process exited cleanly but K8s restarts it → check command │ ├── Exit code 1 → app error → check logs │ ├── Exit code 137 → OOMKilled → increase memory limit │ └── Exit code 143 → SIGTERM not handled → fix graceful shutdown ├── Status: ImagePullBackOff │ ├── Image doesn't exist → check tag/digest │ └── Registry auth fails → check imagePullSecret └── Status: Error / Init:Error └── Init container failed → check init container logs ``` ## Command Cheatsheet ```bash # 1. Overview — what's wrong kubectl get pods -n <ns> -o wide kubectl describe pod <pod> -n <ns> # events section is the first place to look # 2. Logs kubectl logs <pod> -n <ns> # current container kubectl logs <pod> -n <ns> --previous # last crashed container (CrashLoop) kubectl logs <pod> -n <ns> -c <container> # specific container in multi-container pod # 3. Exec into running pod kubectl exec -it <pod> -n <ns> -- /bin/sh # 4. Resource pressure check kubectl top nodes kubectl top pods -n <n...