AWS Certified Solutions Architect – Professional — Question 723

A company hosts an application that uses several Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB). During the initial startup of the EC2 instances, the EC2 instances run user data scripts to download critical content for the application from an Amazon S3 bucket.

The EC2 instances are launching correctly. However, after a period of time, the EC2 instances are terminated with the following error message: "An instance was taken out of service in response to an ELB system health check failure." EC2 instances continue to launch and be terminated because of Auto Scaling events in an endless loop.

The only recent change to the deployment is that the company added a large amount of critical content to the S3 bucket. The company does not want to alter the user data scripts in production.

What should a solutions architect do so that the production environment can deploy successfully?

Answer options

• A. Increase the size of the EC2 instances.
• B. Increase the health check timeout for the ALB.
• C. Change the health check path for the ALB.
• D. Increase the health check grace period for the Auto Scaling group.

Correct answer: C

Explanation

Changing the health check path for the ALB allows the load balancer to monitor a lightweight, static endpoint that is available immediately upon instance startup, rather than a path that depends on the fully downloaded S3 content. This prevents the ALB from marking the instances as unhealthy while the user data scripts are still downloading the newly expanded dataset. Other adjustments, such as increasing the grace period or timeout, may still fail if the download time exceeds those limits, making a dedicated health check path the most robust solution.