Debugging with kubectl debug in Kubernetes - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to start a debug session on a pod named 'webapp'.

Kubernetes

kubectl debug [1] --image=busybox

Drag options to blanks, or click blank then click option'

Adeployment/webapp

Bwebapp

Cservice/webapp

Dpod/webapp

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the resource type prefix like 'pod/'

Using service or deployment instead of pod

You need to specify the pod with the prefix pod/ to debug it directly.

2fill in blank

medium

Complete the command to create a debug pod named 'debugger' based on pod 'api-server'.

Kubernetes

kubectl debug api-server --[1]=debugger --image=busybox

Drag options to blanks, or click blank then click option'

Acopy-to

Bcontainer

Csidecar

Dinit-container

Attempts:

3 left

💡 Hint

Common Mistakes

Using --container instead of --copy-to

Using --sidecar or --init-container which are not valid flags here

The --copy-to flag creates a new debug pod named 'debugger'.

3fill in blank

hard

Fix the error in the command to debug pod 'db' by adding an interactive shell.

Kubernetes

kubectl debug pod/db --image=busybox [1]

Drag options to blanks, or click blank then click option'

A-d

B-it

C--restart=Never

D--rm

Attempts:

3 left

💡 Hint

Common Mistakes

Using -d which runs container detached

Using --restart=Never which controls pod restart policy

Using --rm which removes container after exit but doesn't make it interactive

The -it flag makes the container interactive with a terminal shell.

4fill in blank

hard

Fill both blanks to create a debug pod named 'test-debug' from pod 'backend' with no restart.

Kubernetes

kubectl debug pod/backend --[1]=test-debug --[2]=Never --image=busybox

Drag options to blanks, or click blank then click option'

Acopy-to

Brestart

Crestart-policy

Dcontainer

Attempts:

3 left

💡 Hint

Common Mistakes

Using --restart-policy instead of --restart

Using --container instead of --copy-to

Use --copy-to to name the debug pod and --restart=Never to prevent restarts.

5fill in blank

hard

Fill all three blanks to create a debug pod named 'debugger' based on pod 'cache' with image 'busybox' and interactive shell.

Kubernetes

kubectl debug pod/cache --[1]=debugger --image=[2] [3]

Drag options to blanks, or click blank then click option'

Acopy-to

Bbusybox

C-it

Dcontainer

Attempts:

3 left

💡 Hint

Common Mistakes

Using --container instead of --copy-to

Forgetting -it for interactive shell

Using wrong image name

Use --copy-to to name the debug pod, specify the image busybox, and -it for interactive shell.

Practice

1. What is the main purpose of the kubectl debug command in Kubernetes?

easy

A. To delete a pod and recreate it with debug options

B. To permanently change the pod's container image

C. To scale the number of pod replicas for debugging

D. To add a temporary container with debugging tools to a running pod

Solution

1. Step 1: Understand the purpose of kubectl debug

   This command adds a temporary container to a running pod for debugging without changing the original pod.

2. Step 2: Compare other options

   Options A, B, and D describe permanent or unrelated actions, not the temporary debugging feature.

3. Final Answer:

   To add a temporary container with debugging tools to a running pod -> Option D

4. Quick Check:

   Temporary debug container = C [OK]

Hint: Remember: debug adds temporary tools, no permanent pod change [OK]

Common Mistakes:

• Thinking debug changes pod image permanently
• Confusing debug with pod scaling
• Assuming debug deletes pods

2. Which of the following is the correct syntax to start a debug session on a pod named webapp-123?

easy

A. kubectl debug --pod webapp-123 --image=busybox

B. kubectl debug webapp-123 -image=busybox

C. kubectl debug pod/webapp-123 --image=busybox

D. kubectl debug pod webapp-123 --image=busybox

Solution

1. Step 1: Recall correct kubectl debug syntax

   The correct syntax uses kubectl debug pod/NAME --image=IMAGE to specify the pod and debug container image.

2. Step 2: Analyze options

   kubectl debug pod/webapp-123 --image=busybox matches the correct syntax exactly. Options A, B, and C have syntax errors or missing slashes.

3. Final Answer:

   kubectl debug pod/webapp-123 --image=busybox -> Option C

4. Quick Check:

   Correct syntax includes 'pod/' prefix = D [OK]

Hint: Use 'pod/NAME' format with --image option for debug [OK]

Common Mistakes:

• Omitting 'pod/' prefix before pod name
• Using spaces instead of slash between 'pod' and name
• Misplacing --image option

3. What will be the output of this command if the pod api-server-1 does not exist?

kubectl debug pod/api-server-1 --image=busybox

medium

A. Error: pods "api-server-1" not found

B. A new debug container starts successfully

C. Pod is deleted and recreated with debug image

D. Command runs but no debug container is added

Solution

1. Step 1: Understand pod existence requirement

   The kubectl debug command requires the target pod to exist to add a debug container.

2. Step 2: Predict command behavior if pod missing

   If the pod does not exist, kubectl returns an error indicating the pod was not found.

3. Final Answer:

   Error: pods "api-server-1" not found -> Option A

4. Quick Check:

   Missing pod causes 'not found' error = A [OK]

Hint: Check pod exists before debug; else 'not found' error [OK]

Common Mistakes:

• Assuming debug creates pod if missing
• Expecting debug to run silently without pod
• Confusing debug with pod creation commands

4. You run kubectl debug pod/myapp --image=busybox but get an error: error: container busybox not found. What is the likely cause?

medium

A. The debug container image is missing or misspelled

B. The pod does not exist

C. The pod already has a container named busybox

D. kubectl debug requires root privileges

Solution

1. Step 1: Analyze the error message

   The error says 'container busybox not found', which usually means the image name is incorrect or missing.

2. Step 2: Check common causes

   The debug container image is missing or misspelled fits because a misspelled or missing image causes this error. The pod existence or privileges are unrelated.

3. Final Answer:

   The debug container image is missing or misspelled -> Option A

4. Quick Check:

   Image name errors cause 'container not found' message [OK]

Hint: Verify debug image name spelling and availability [OK]

Common Mistakes:

• Assuming pod absence causes this error
• Thinking debug needs root privileges
• Confusing container name with image name

5. You want to debug a running pod backend-0 but need to run a shell with root privileges inside the debug container. Which command correctly achieves this?

hard

A. kubectl debug pod/backend-0 --image=busybox --target=backend-0 -- sh

B. kubectl debug pod/backend-0 --image=busybox --privileged -- sh

C. kubectl debug pod/backend-0 --image=busybox --container=debugger -- sh

D. kubectl debug pod/backend-0 --image=busybox --as-root -- sh

Solution

1. Step 1: Identify how to run debug container with root

   The --privileged flag allows the debug container to run with root privileges.

2. Step 2: Check command correctness

   kubectl debug pod/backend-0 --image=busybox --privileged -- sh uses --privileged and runs shell sh, which is correct. Other options misuse flags or do not enable root.

3. Final Answer:

   kubectl debug pod/backend-0 --image=busybox --privileged -- sh -> Option B

4. Quick Check:

   Use --privileged to get root shell in debug container [OK]

Hint: Add --privileged flag to run debug container as root [OK]

Common Mistakes:

• Using nonexistent flags like --as-root
• Confusing --target with privilege escalation
• Omitting --privileged when root shell needed