AWS DevOps Engineer Professional Practice Test

What happens when auto-scaling is not suspended during a deployment?

1. Only old versions will run

2. New instances may launch with the previous application version

3. Deployment will fail

4. Application performance will improve

The correct answer is: New instances may launch with the previous application version

When auto-scaling is not suspended during a deployment, new instances may launch with the previous application version. This occurs because, without suspension, the auto-scaling group continues to manage the instances based on the current scaling policies and metrics. As a result, if there are any scaling events triggered during the deployment, new instances can be created, potentially pulling the old application version from the Amazon Machine Images (AMIs) or container registry, which is set before the deployment process began. This situation can lead to a scenario where the application ends up with a mix of different versions running simultaneously. It can cause confusion and inconsistencies in application behavior, as traffic may be routed to both the newly deployed instances and the instances running the previous version. Consequently, this emphasizes the importance of managing the deployment environment carefully, especially in a highly dynamic environment where auto-scaling is actively responding to load changes.