Rolling update strategy in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Rolling Update Basics

What is the main advantage of using a rolling update strategy in Kubernetes deployments?

A It updates pods one at a time, ensuring service availability during updates.

B It pauses the deployment until manual approval is given for each pod.

C It updates all pods simultaneously, minimizing downtime.

D It deletes all old pods before creating new ones to save resources.

💡 Hint

Think about how service availability is maintained during updates.

Rolling updates replace pods gradually, one by one, so the application stays available without downtime.

💻 Command Output

intermediate

Interpreting Rolling Update Status

What is the output of the following command if a rolling update is in progress and 2 out of 5 pods have been updated?

Kubernetes

kubectl rollout status deployment/myapp

A Waiting for rollout to finish: 3 old replicas are pending termination...

B Waiting for rollout to finish: 2 out of 5 new replicas are available...

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

D deployment "myapp" successfully rolled out

💡 Hint

Look for messages indicating partial progress in rollout.

The command shows how many new pods are available during the rolling update process.

❓ Configuration

advanced

Configuring Max Surge and Max Unavailable

Given this deployment snippet, what is the maximum number of pods that can be unavailable during the rolling update?

strategy:
  type: RollingUpdate
  rollingUpdate:
    maxSurge: 2
    maxUnavailable: 1

A 1 pod can be unavailable at once

B 2 pods can be unavailable at once

C No pods can be unavailable during update

D 3 pods can be unavailable at once

💡 Hint

Check the value of maxUnavailable in the configuration.

The maxUnavailable field controls how many pods can be down during the update. Here it is set to 1.

❓ Troubleshoot

advanced

Troubleshooting a Stuck Rolling Update

You started a rolling update but it is stuck and not progressing. Which of the following is the most likely cause?

A The old pods are terminating too quickly, causing downtime.

B The deployment has <code>maxSurge</code> set to 0, allowing no extra pods.

C The new pods are failing readiness probes, so they are not marked ready.

D The deployment strategy is set to Recreate instead of RollingUpdate.

💡 Hint

Consider what prevents new pods from becoming available during update.

If readiness probes fail, new pods won't be ready, so the update waits indefinitely.

🔀 Workflow

expert

Rolling Update Workflow Steps

Arrange the steps of a Kubernetes rolling update in the correct order.

A 1,3,2,4

B 3,1,2,4

C 2,1,3,4

D 1,2,3,4

💡 Hint

Think about how new pods are created and verified before old pods are removed.

The rolling update first creates new pods (up to maxSurge), waits for readiness, then removes old pods (up to maxUnavailable), repeating until done.