Google Cloud Professional Cloud Network Engineer — Question 5

You have an application that is running in a managed instance group. Your development team has released an updated instance template which contains a new feature which was not heavily tested. You want to minimize impact to users if there is a bug in the new template.
How should you update your instances?

Answer options

• A. Manually patch some of the instances, and then perform a rolling restart on the instance group.
• B. Using the new instance template, perform a rolling update across all instances in the instance group. Verify the new feature once the rollout completes.
• C. Deploy a new instance group and canary the updated template in that group. Verify the new feature in the new canary instance group, and then update the original instance group.
• D. Perform a canary update by starting a rolling update and specifying a target size for your instances to receive the new template. Verify the new feature on the canary instances, and then roll forward to the rest of the instances.

Correct answer: D

Explanation

Option D is correct because it allows for a controlled rollout of the new template, enabling verification of the new feature on canary instances before applying the update to the rest. Option A is not ideal as it does not ensure testing across the entire group. Option B risks affecting all users at once without prior verification. Option C, while safer, involves unnecessary duplication of instance groups.