Lab: ConfigMap/Secret Miswire

Goal

You will learn to diagnose a workload that fails due to missing configuration: confirm whether the ConfigMap/Secret exists, whether keys match, and whether the pod spec references them correctly.

• Prove object existence.
• Prove key names.
• Prove pod spec wiring.

Scenario

A Deployment starts crashing after a change. Logs show a missing environment variable or a missing file. The cluster is healthy; the wiring is not.

Inspect the references

Start with the pod spec: env, envFrom, and mounts.

• Names are namespace-scoped.
• Keys are case-sensitive; one character is the difference between stable and broken.

kubectl describe pod <pod> -n <ns>
kubectl get pod <pod> -n <ns> -o yaml | rg -n "env:|envFrom:|configMapKeyRef|secretKeyRef|volumes:|volumeMounts:"

kubectl get configmap,secret -n <ns>

Fix and verify

Fix the governing reference, then roll the workload once.

• Correct the name/key in the manifest (or create the missing object).
• Avoid manual pod deletes until you understand why the next pod will be better.
• After fix: `kubectl rollout restart deploy/<name> -n <ns>` and watch events.