AWS Certified Solutions Architect – Associate (SAA-C03) — Question 372

A company is migrating its on-premises workload to the AWS Cloud. The company already uses several Amazon EC2 instances and Amazon RDS DB instances. The company wants a solution that automatically starts and stops the EC2 instances and DB instances outside of business hours. The solution must minimize cost and infrastructure maintenance.

Which solution will meet these requirements?

Answer options

• A. Scale the EC2 instances by using elastic resize. Scale the DB instances to zero outside of business hours.
• B. Explore AWS Marketplace for partner solutions that will automatically start and stop the EC2 instances and DB instances on a schedule.
• C. Launch another EC2 instance. Configure a crontab schedule to run shell scripts that will start and stop the existing EC2 instances and DB instances on a schedule.
• D. Create an AWS Lambda function that will start and stop the EC2 instances and DB instances. Configure Amazon EventBridge to invoke the Lambda function on a schedule.

Correct answer: D

Explanation

Using AWS Lambda combined with Amazon EventBridge provides a fully serverless, low-cost solution that requires zero infrastructure maintenance. Running a dedicated EC2 instance with cron jobs as suggested in Option C introduces unnecessary management overhead and continuous compute costs. Option A is invalid because Amazon RDS DB instances cannot be scaled to zero, and Option B introduces additional licensing and third-party management costs.