CKAD — Debugging Pods

5-Step Debugging Workflow

When a Pod isn’t working, follow these steps in order:

Step 1: Check Pod Status

kubectl get pod my-pod
kubectl get pod my-pod -o wide

# Common problem statuses:
# CrashLoopBackOff — Container keeps crashing
# ImagePullBackOff — Cannot pull the container image
# Pending         — Cannot be scheduled
# Error           — Container exited with error
# OOMKilled       — Container ran out of memory

Step 2: Describe the Pod

kubectl describe pod my-pod

Focus on these sections:

• Status — Current Pod phase
• Conditions — Ready, Initialized, ContainersReady
• Events — Recent events (scheduling, pulling, starting, probe failures)
• State / Last State — Current and previous container state with exit codes

Step 3: Check Events

# All events in the namespace (sorted by time)
kubectl get events --sort-by=.lastTimestamp

# Events for a specific Pod
kubectl get events --field-selector involvedObject.name=my-pod

Step 4: Execute Commands Inside the Container

# Run a command
kubectl exec my-pod -- ls /app
kubectl exec my-pod -- cat /etc/config/app.yaml
kubectl exec my-pod -- env

# Interactive shell
kubectl exec -it my-pod -- /bin/sh
kubectl exec -it my-pod -- /bin/bash

# Specific container in multi-container Pod
kubectl exec -it my-pod -c sidecar -- /bin/sh

Step 5: Check Resource Usage

# Pod CPU and memory usage (requires metrics-server)
kubectl top pod my-pod
kubectl top pods -l app=web

# Node resource usage
kubectl top nodes

Debugging cheat sheet: get → describe → events → logs --previous → exec. This order covers 90% of debugging scenarios on the exam.

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Next: Common Pod Problems