Executing commands in Pods in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of command executed inside a Pod

You run the command kubectl exec mypod -- ls /app on a Pod named mypod. The Pod's /app directory contains files index.html and config.yaml. What will be the output?

A

index.html
config.yaml

B

mypod
index.html
config.yaml

C Error: directory not found

D No resources found.

💡 Hint

The kubectl exec command runs the given command inside the Pod's container.

The ls /app command lists files inside the /app directory of the Pod. Since the directory contains index.html and config.yaml, these are listed.

🧠 Conceptual

intermediate

Understanding kubectl exec command syntax

Which of the following is the correct syntax to execute the command cat /etc/hosts inside a Pod named webserver?

A kubectl exec --webserver cat /etc/hosts

B kubectl exec webserver -- cat /etc/hosts

C kubectl exec webserver cat /etc/hosts

D kubectl exec -- pod=webserver -- cat /etc/hosts

💡 Hint

The Pod name comes immediately after kubectl exec, followed by -- to separate the command.

The correct syntax is kubectl exec POD_NAME -- COMMAND. Option B follows this format exactly.

❓ Troubleshoot

advanced

Troubleshooting kubectl exec permission error

You try to run kubectl exec mypod -- whoami but get the error: error: unable to upgrade connection: Forbidden. What is the most likely cause?

A The Kubernetes API server is down

B The Pod does not exist

C The command <code>whoami</code> is not installed in the Pod

D The user running kubectl lacks permission to exec into the Pod

💡 Hint

The error mentions 'Forbidden', which relates to permissions.

The 'Forbidden' error means the user does not have RBAC permissions to exec into the Pod. The Pod existing or command presence would cause different errors.

🔀 Workflow

advanced

Executing an interactive shell inside a Pod

You want to open an interactive bash shell inside a Pod named backend. Which command should you use?

A kubectl exec -it backend -- /bin/bash

B kubectl exec backend /bin/bash -i

C kubectl exec backend --interactive /bin/bash

D kubectl exec backend -bash -it

💡 Hint

Use flags -i and -t for interactive terminal.

The correct command uses -it flags before the Pod name and -- to separate the command. Option A is correct.

✅ Best Practice

expert

Best practice for running commands in multi-container Pods

A Pod has two containers: app and sidecar. You want to run ls /data inside the sidecar container. Which command is correct?

A kubectl exec mypod --container sidecar ls /data

B kubectl exec mypod --container sidecar -- ls /data

C kubectl exec mypod -c sidecar -- ls /data

D kubectl exec mypod --container=sidecar ls /data

💡 Hint

Use -c or --container with kubectl exec to specify container.

The correct syntax is kubectl exec POD -c CONTAINER -- COMMAND. Option C uses the short flag -c correctly. Options B and C have wrong flag usage or missing --. Option C misses -- separator.