Rollback to previous version in Kubernetes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a rollback in Kubernetes?

A rollback in Kubernetes means returning a deployment to a previous stable version when the current version has issues.

beginner

Which command rolls back a deployment to its previous version?

kubectl rollout undo deployment/

intermediate

How can you check the rollout history of a deployment?

Use the command: kubectl rollout history deployment/ to see past versions and revisions.

intermediate

What happens if you run 'kubectl rollout undo' without specifying a revision?

Kubernetes rolls back the deployment to the immediately previous revision by default.

intermediate

How do you rollback to a specific revision number?

Use: kubectl rollout undo deployment/ --to-revision=

What command shows the rollout status of a deployment?

A kubectl get pods

B kubectl rollout status deployment/<deployment-name>

C kubectl describe deployment

D kubectl logs deployment/<deployment-name>

The command 'kubectl rollout status deployment/' shows the current rollout status.

What does 'kubectl rollout undo deployment/myapp' do?

A Rolls back 'myapp' deployment to the previous version

B Deletes the 'myapp' deployment

C Updates 'myapp' deployment to the latest version

D Shows logs of 'myapp' deployment

This command rolls back the deployment named 'myapp' to its previous version.

How do you see all previous revisions of a deployment?

A kubectl rollout history deployment/<deployment-name>

B kubectl get revisions deployment/<deployment-name>

C kubectl describe pods

D kubectl get deployments

The 'kubectl rollout history' command lists all past revisions of a deployment.

If you want to rollback to revision 3, which command should you use?

A kubectl undo deployment/<deployment-name> revision 3

B kubectl rollback deployment/<deployment-name> revision=3

C kubectl rollout undo deployment/<deployment-name> --to-revision=3

D kubectl revert deployment/<deployment-name> 3

The correct syntax to rollback to a specific revision is using '--to-revision' flag.

What is the default behavior of 'kubectl rollout undo' if no revision is specified?

A Rollback to the latest revision

B Rollback to the first revision

C No rollback happens

D Rollback to the previous revision

By default, it rolls back to the immediately previous revision.

Explain how to rollback a Kubernetes deployment to a previous version and how to check its history.

Think about commands to undo and to see past versions.

Describe the steps and commands to rollback to a specific revision number in Kubernetes.

Focus on how to target a specific past version.

Practice

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

easy

A. It updates the deployment 'myapp' to the latest image version.

B. It rolls back the deployment 'myapp' to its previous version.

C. It deletes the deployment 'myapp' permanently.

D. It scales the deployment 'myapp' to zero replicas.

Solution

1. Step 1: Understand the command purpose

   The command kubectl rollout undo is used to revert a deployment to a previous state.

2. Step 2: Apply to the given deployment

   Using deployment/myapp specifies which deployment to rollback.

3. Final Answer:

   It rolls back the deployment 'myapp' to its previous version. -> Option B

4. Quick Check:

   Rollback command = revert deployment [OK]

Hint: Rollback uses 'kubectl rollout undo' with deployment name [OK]

Common Mistakes:

• Confusing rollback with delete command
• Thinking it updates to latest version instead of previous
• Using scale command instead of rollback

2. Which of the following is the correct syntax to rollback a deployment named 'webapp' to its previous version?

easy

A. kubectl rollout undo deployment/webapp

B. kubectl rollback deployment/webapp

C. kubectl undo deployment webapp

D. kubectl rollback undo webapp

Solution

1. Step 1: Recall correct rollback syntax

   The correct command to rollback is kubectl rollout undo deployment/<name>.

2. Step 2: Match syntax with deployment name

   Replacing <name> with 'webapp' gives kubectl rollout undo deployment/webapp.

3. Final Answer:

   kubectl rollout undo deployment/webapp -> Option A

4. Quick Check:

   Correct rollback syntax = rollout undo [OK]

Hint: Remember 'rollout undo' is the rollback command [OK]

Common Mistakes:

• Using 'rollback' instead of 'rollout undo'
• Incorrect order of words in command
• Missing 'deployment/' prefix

3. Given the following commands executed in order:

kubectl apply -f deployment-v1.yaml
kubectl apply -f deployment-v2.yaml
kubectl rollout undo deployment/myapp

What will be the current version of the deployment 'myapp' after the last command?

medium

A. Version 1 (deployment-v1.yaml)

B. Version 2 (deployment-v2.yaml)

C. No change, still version 2

D. Deployment deleted

Solution

1. Step 1: Understand deployment updates

   First, version 1 is applied, then version 2 updates the deployment.

2. Step 2: Rollback command effect

   The rollback command reverts the deployment to the previous version, which is version 1.

3. Final Answer:

   Version 1 (deployment-v1.yaml) -> Option A

4. Quick Check:

   Rollback reverts to last version before update [OK]

Hint: Rollback returns to version before last update [OK]

Common Mistakes:

• Assuming rollback deletes deployment
• Thinking rollback keeps current version
• Confusing rollback with reapply

4. You tried to rollback a deployment using kubectl rollout undo deployment/myapp but got an error: error: no rollout found. What is the most likely cause?

medium

A. Rollback command requires a namespace flag.

B. You misspelled the deployment name in the command.

C. The deployment 'myapp' has no previous versions to rollback to.

D. The Kubernetes cluster is down.

Solution

1. Step 1: Analyze the error message

   The error 'no rollout found' means no previous rollout history exists for rollback.

2. Step 2: Identify cause

   This usually happens if the deployment was never updated or has only one version.

3. Final Answer:

   The deployment 'myapp' has no previous versions to rollback to. -> Option C

4. Quick Check:

   No rollout history = no rollback possible [OK]

Hint: Check rollout history before rollback [OK]

Common Mistakes:

• Assuming cluster is down causes this error
• Forgetting to check deployment name spelling
• Thinking rollback always works without history

5. You have a deployment 'api-server' with three revisions in history. You want to rollback to revision 2 specifically. Which command should you use?

hard

A. kubectl rollout undo deployment/api-server revision=2

B. kubectl rollback deployment/api-server --revision=2

C. kubectl undo deployment/api-server revision 2

D. kubectl rollout undo deployment/api-server --to-revision=2

Solution

1. Step 1: Recall rollback to specific revision syntax

   The correct syntax to rollback to a specific revision is kubectl rollout undo deployment/<name> --to-revision=<number>.

2. Step 2: Apply to 'api-server' and revision 2

   Replacing placeholders gives kubectl rollout undo deployment/api-server --to-revision=2.

3. Final Answer:

   kubectl rollout undo deployment/api-server --to-revision=2 -> Option D

4. Quick Check:

   Use '--to-revision' flag to rollback specific version [OK]

Hint: Use '--to-revision' flag to rollback specific version [OK]

Common Mistakes:

• Using incorrect flags like --revision or wrong command order
• Omitting '--to-revision' flag
• Using 'rollback' instead of 'rollout undo'