Deployment status and history in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Check the rollout status of a deployment

You run the command kubectl rollout status deployment/myapp. What output indicates the deployment has successfully rolled out?

A deployment "myapp" successfully rolled out

B Error from server (NotFound): deployments.apps "myapp" not found

C deployment "myapp" failed to rollout

D Waiting for deployment "myapp" rollout to finish: 1 out of 3 new replicas have been updated...

💡 Hint

Look for a message confirming success, not errors or partial updates.

The command kubectl rollout status deployment/myapp shows the current rollout status. The message deployment "myapp" successfully rolled out means the deployment finished updating all pods successfully.

🧠 Conceptual

intermediate

Understanding deployment revision history

What does the command kubectl rollout history deployment/myapp show?

A A list of all revisions of the deployment with change causes

B The YAML manifest of the deployment

C The status of all pods in the deployment

D The current pod logs for the deployment

💡 Hint

Think about what 'history' means in this context.

The kubectl rollout history command lists all previous revisions of a deployment, showing when and why changes were made.

❓ Troubleshoot

advanced

Diagnosing a stuck deployment rollout

You notice a deployment rollout is stuck and not progressing. Which command helps you see detailed rollout status including pod conditions?

A kubectl get pods --all-namespaces

B kubectl describe deployment myapp

C kubectl logs deployment/myapp

D kubectl rollout undo deployment/myapp

💡 Hint

You want detailed info about the deployment and its pods.

kubectl describe deployment myapp shows detailed info including events and pod status that help diagnose rollout issues.

🔀 Workflow

advanced

Rollback a deployment to a previous revision

You want to rollback the deployment myapp to revision 2. Which command correctly performs this rollback?

A kubectl revert deployment/myapp --revision 2

B kubectl rollback deployment myapp --revision=2

C kubectl undo deployment myapp revision 2

D kubectl rollout undo deployment/myapp --to-revision=2

💡 Hint

Check the exact syntax for rollback with revision number.

The correct syntax to rollback to a specific revision is kubectl rollout undo deployment/myapp --to-revision=2.

✅ Best Practice

expert

Best practice for monitoring deployment history in production

Which approach is best to keep track of deployment history and changes in a Kubernetes production environment?

A Manually save deployment YAML files on local machines after each change

B Rely only on <code>kubectl get pods</code> to check running pods after deployment

C Use <code>kubectl rollout history</code> combined with GitOps to track deployment manifests and changes

D Use <code>kubectl logs</code> of pods to track deployment changes

💡 Hint

Think about combining Kubernetes tools with version control for best tracking.

Combining kubectl rollout history with GitOps practices ensures deployment changes are tracked both in Kubernetes and version control, enabling audit and rollback.

Practice

1. What does the command kubectl rollout status deployment/myapp do in Kubernetes?

easy

A. It shows if the deployment named 'myapp' is successfully running or still updating.

B. It deletes the deployment named 'myapp' from the cluster.

C. It creates a new deployment named 'myapp'.

D. It lists all pods running in the cluster.

Solution

1. Step 1: Understand the command purpose

   The command kubectl rollout status checks the current status of a deployment rollout.

2. Step 2: Apply to the specific deployment

   Using deployment/myapp targets the deployment named 'myapp' to see if it is running or updating.

3. Final Answer:

   It shows if the deployment named 'myapp' is successfully running or still updating. -> Option A

4. Quick Check:

   Rollout status = Deployment running status [OK]

Hint: Use rollout status to check deployment health quickly [OK]

Common Mistakes:

• Confusing rollout status with deployment creation
• Thinking it deletes or lists pods
• Using wrong resource type after rollout status

2. Which of the following is the correct syntax to view the rollout history of a deployment named 'webapp'?

easy

A. kubectl get rollout history webapp

B. kubectl describe rollout webapp

C. kubectl rollout status deployment/webapp

D. kubectl rollout history deployment/webapp

Solution

1. Step 1: Identify the correct command for rollout history

   The command to view rollout history is kubectl rollout history.

2. Step 2: Use correct resource type and name

   Appending deployment/webapp specifies the deployment named 'webapp'.

3. Final Answer:

   kubectl rollout history deployment/webapp -> Option D

4. Quick Check:

   Rollout history syntax = kubectl rollout history deployment/name [OK]

Hint: Remember: rollout history shows past changes, rollout status shows current state [OK]

Common Mistakes:

• Using 'get' or 'describe' instead of 'rollout history'
• Omitting 'deployment/' prefix
• Confusing rollout status with rollout history

3. Given the command output:

deployment "frontend" successfully rolled out

What command was most likely run to get this output?

medium

A. kubectl get pods -l app=frontend

B. kubectl rollout history deployment/frontend

C. kubectl rollout status deployment/frontend

D. kubectl describe deployment frontend

Solution

1. Step 1: Analyze the output message

   The message says the deployment "frontend" was successfully rolled out, indicating a status check.

2. Step 2: Match output to command

   kubectl rollout status shows this success message, while history or describe commands show different outputs.

3. Final Answer:

   kubectl rollout status deployment/frontend -> Option C

4. Quick Check:

   Success rollout message = rollout status command [OK]

Hint: Success message means rollout status was checked [OK]

Common Mistakes:

• Confusing rollout history output with status output
• Assuming pod listing shows rollout success
• Using describe which shows detailed info, not status message

4. You ran kubectl rollout history deployment/api but got an error: error: deployments.apps "api" not found. What is the most likely cause?

medium

A. The Kubernetes cluster is down.

B. The deployment named 'api' does not exist in the current namespace.

C. You need to add '--all-namespaces' to see the deployment.

D. The command syntax is incorrect; 'rollout history' is invalid.

Solution

1. Step 1: Understand the error message

   The error says deployment "api" not found, meaning Kubernetes can't find that deployment in the current namespace.

2. Step 2: Check command and context

   The command syntax is correct, and cluster down would cause different errors. Missing deployment is the most likely cause.

3. Final Answer:

   The deployment named 'api' does not exist in the current namespace. -> Option B

4. Quick Check:

   Deployment not found error = deployment missing [OK]

Hint: Check deployment name and namespace if 'not found' error appears [OK]

Common Mistakes:

• Assuming syntax error when command is correct
• Forgetting namespace context
• Blaming cluster status without checking deployment

5. You want to rollback your deployment 'backend' to the previous version after a failed update. Which sequence of commands correctly checks the history and rolls back?

hard

A. kubectl rollout history deployment/backendkubectl rollout undo deployment/backend

B. kubectl rollout status deployment/backendkubectl delete deployment/backend

C. kubectl get pods -l app=backendkubectl rollout history deployment/backend

D. kubectl rollout undo deployment/backendkubectl rollout history deployment/backend

Solution

1. Step 1: Check rollout history

   Use kubectl rollout history deployment/backend to see past versions and confirm rollback target.

2. Step 2: Rollback to previous version

   Use kubectl rollout undo deployment/backend to revert to the last successful deployment.

3. Final Answer:

   kubectl rollout history deployment/backend followed by kubectl rollout undo deployment/backend -> Option A

4. Quick Check:

   History then undo = safe rollback steps [OK]

Hint: Always check history before undoing a rollout [OK]

Common Mistakes:

• Deleting deployment instead of rolling back
• Undoing before checking history
• Confusing status command with rollback