AWS Certified Solutions Architect – Associate (SAA-C03) — Question 442

A company hosts a multi-tier web application on Amazon Linux Amazon EC2 instances behind an Application Load Balancer. The instances run in an Auto Scaling group across multiple Availability Zones. The company observes that the Auto Scaling group launches more On-Demand Instances when the application's end users access high volumes of static web content. The company wants to optimize cost.

What should a solutions architect do to redesign the application MOST cost-effectively?

Answer options

• A. Update the Auto Scaling group to use Reserved Instances instead of On-Demand Instances.
• B. Update the Auto Scaling group to scale by launching Spot Instances instead of On-Demand Instances.
• C. Create an Amazon CloudFront distribution to host the static web contents from an Amazon S3 bucket.
• D. Create an AWS Lambda function behind an Amazon API Gateway API to host the static website contents.

Correct answer: C

Explanation

Offloading static assets to Amazon S3 and caching them using Amazon CloudFront is the most cost-effective strategy because it prevents the EC2 instances from having to process static content requests, thereby avoiding unnecessary scaling events. While modifying the Auto Scaling group to use Spot or Reserved Instances (Options A and B) lowers compute costs, it does not fix the root architectural inefficiency of serving static files from EC2. Using AWS Lambda and API Gateway (Option D) to host static content is more complex and far more expensive at scale than using S3 and CloudFront.