Debugging with kubectl debug in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of kubectl debug creating ephemeral container

What is the output when running this command to add an ephemeral debug container to a running pod named webapp in namespace prod?

Kubernetes

kubectl debug -n prod -it webapp --image=busybox --target=webapp -- sh

A ephemeralcontainers "webapp-debugger" created in pod webapp

B Pod/webapp created in namespace prod

C Error from server (NotFound): pods "webapp" not found

D Warning: image busybox not found locally, pulling...

💡 Hint

Think about what kubectl debug does when adding ephemeral containers.

The command adds an ephemeral container named webapp-debugger to the existing pod webapp. The output confirms creation of the ephemeral container.

❓ Troubleshoot

intermediate

Troubleshooting kubectl debug failure due to missing target

You run kubectl debug -it mypod --image=busybox --target=app but get an error. What is the most likely cause?

A The image busybox is not available in the cluster

B The pod mypod does not exist in the current namespace

C The container named app does not exist in pod mypod

D kubectl debug requires --container flag instead of --target

💡 Hint

Check if the container name matches exactly inside the pod.

The --target flag specifies the container inside the pod to debug. If the container name is wrong or missing, kubectl debug fails with an error.

❓ Configuration

advanced

Configuring a pod to allow ephemeral containers

Which pod spec snippet correctly enables ephemeral containers for debugging?

A

spec:
  enableEphemeralContainers: true

B

metadata:
  annotations:
    ephemeral-containers.kubernetes.io/enabled: "true"

C

spec:
  ephemeralContainers:
  - name: debug
    image: busybox

D No special configuration is needed; ephemeral containers are enabled by default

💡 Hint

Consider the default Kubernetes behavior for ephemeral containers.

Ephemeral containers are enabled by default in Kubernetes 1.23+ and do not require special pod spec configuration.

✅ Best Practice

advanced

Best practice for debugging a pod with kubectl debug

What is the recommended approach to debug a running pod without disrupting its main containers?

A Delete the pod and recreate it with a debug container

B Add an ephemeral container using kubectl debug

C Modify the pod spec to add a permanent debug container

D Use kubectl exec to run commands inside the main container

💡 Hint

Think about non-disruptive debugging methods.

Adding an ephemeral container allows debugging without stopping or changing the main containers, minimizing disruption.

🧠 Conceptual

expert

Understanding ephemeral container lifecycle

Which statement about ephemeral containers added via kubectl debug is TRUE?

A Ephemeral containers are intended for temporary debugging and do not restart automatically

B Ephemeral containers restart automatically if they exit

C Ephemeral containers share the same lifecycle as the pod's main containers

D Ephemeral containers require pod restart to be removed

💡 Hint

Consider how ephemeral containers behave compared to normal containers.

Ephemeral containers are temporary and do not restart automatically if they exit; they are meant for short-term debugging.