AWS Certified Solutions Architect – Associate (SAA-C02) — Question 756

A company is migrating a distributed application to AWS. The application serves variable workloads. The legacy platform consists of a primary server that coordinates jobs across multiple compute nodes. The company wants to modernize the application with a solution that maximizes resiliency and scalability.
How should a solutions architect design the architecture to meet these requirements?

Answer options

• A. Configure an Amazon Simple Queue Service (Amazon SQS) queue as a destination for the jobs. Implement the compute nodes with Amazon EC2 instances that are managed in an Auto Scaling group. Configure EC2 Auto Scaling to use scheduled scaling.
• B. Configure an Amazon Simple Queue Service (Amazon SQS) queue as a destination for the jobs. Implement the compute nodes with Amazon EC2 instances that are managed in an Auto Scaling group. Configure EC2 Auto Scaling based on the size of the queue.
• C. Implement the primary server and the compute nodes with Amazon EC2 instances that are managed in an Auto Scaling group. Configure AWS CloudTrail as a destination for the jobs. Configure EC2 Auto Scaling based on the load on the primary server.
• D. Implement the primary server and the compute nodes with Amazon EC2 instances that are managed in an Auto Scaling group. Configure Amazon EventBridge (Amazon CloudWatch Events) as a destination for the jobs. Configure EC2 Auto Scaling based on the load on the compute nodes.

Correct answer: B

Explanation

Using an Amazon SQS queue decouples the application components, which increases resiliency by ensuring jobs are not lost if compute nodes fail. Scaling the Amazon EC2 Auto Scaling group dynamically based on the queue depth (size) ensures that the compute capacity automatically matches the variable workload demands. Other options either use scheduled scaling, which does not handle unpredictable variable workloads, or use services like AWS CloudTrail and EventBridge incorrectly for job queueing.