AWS Certified Solutions Architect – Associate (SAA-C03) — Question 129

A company uses a three-tier web application to provide training to new employees. The application is accessed for only 12 hours every day. The company is using an Amazon RDS for MySQL DB instance to store information and wants to minimize costs.
What should a solutions architect do to meet these requirements?

Answer options

• A. Configure an IAM policy for AWS Systems Manager Session Manager. Create an IAM role for the policy. Update the trust relationship of the role. Set up automatic start and stop for the DB instance.
• B. Create an Amazon ElastiCache for Redis cache cluster that gives users the ability to access the data from the cache when the DB instance is stopped. Invalidate the cache after the DB instance is started.
• C. Launch an Amazon EC2 instance. Create an IAM role that grants access to Amazon RDS. Attach the role to the EC2 instance. Configure a cron job to start and stop the EC2 instance on the desired schedule.
• D. Create AWS Lambda functions to start and stop the DB instance. Create Amazon EventBridge (Amazon CloudWatch Events) scheduled rules to invoke the Lambda functions. Configure the Lambda functions as event targets for the rules.

Correct answer: D

Explanation

Option D is correct because using AWS Lambda functions to start and stop the DB instance, combined with scheduled EventBridge rules, automates the process efficiently and minimizes costs during off-hours. Option A does not directly manage the DB instance's operational hours. Option B suggests using a cache which does not reduce costs effectively when the database is not running. Option C involves an EC2 instance which adds unnecessary complexity and cost compared to the serverless approach of Lambda.