AWS Certified Solutions Architect – Associate (SAA-C03) — Question 728

An ecommerce company is running a seasonal online sale. The company hosts its website on Amazon EC2 instances spanning multiple Availability Zones. The company wants its website to manage sudden traffic increases during the sale.

Which solution will meet these requirements MOST cost-effectively?

Answer options

• A. Create an Auto Scaling group that is large enough to handle peak traffic load. Stop half of the Amazon EC2 instances. Configure the Auto Scaling group to use the stopped instances to scale out when traffic increases.
• B. Create an Auto Scaling group for the website. Set the minimum size of the Auto Scaling group so that it can handle high traffic volumes without the need to scale out.
• C. Use Amazon CloudFront and Amazon ElastiCache to cache dynamic content with an Auto Scaling group set as the origin. Configure the Auto Scaling group with the instances necessary to populate CloudFront and ElastiCache. Scale in after the cache is fully populated.
• D. Configure an Auto Scaling group to scale out as traffic increases. Create a launch template to start new instances from a preconfigured Amazon Machine Image (AMI).

Correct answer: D

Explanation

Option D is the most cost-effective solution because dynamic scaling allows the infrastructure to expand automatically in response to traffic demand and shrink when demand drops, ensuring the company only pays for what it uses. Options A and B require keeping idle or over-provisioned resources running, which leads to unnecessary costs. Option C is incorrect because caching dynamic content in this manner is inefficient and scaling down the origin group prematurely could lead to application failures during cache misses.