Exam AWS Certified Solutions Architect - Associate SAA-C03 topic 1 question 959 discussion

If State Manager does not fully meet your needs, you can also use AWS Lambda with Amazon EventBridge to achieve similar functionality. This approach provides more flexibility but requires additional setup and management https://docs.aws.amazon.com/prescriptive-guidance/latest/patterns/automatically-stop-and-start-an-amazon-rds-db-instance-using-aws-systems-manager-maintenance-windows.html

You are right: AWS Systems Manager has limitations (https://docs.aws.amazon.com/prescriptive-guidance/latest/patterns/automatically-stop-and-start-an-amazon-rds-db-instance-using-aws-systems-manager-maintenance-windows.html#automatically-stop-and-start-an-amazon-rds-db-instance-using-aws-systems-manager-maintenance-windows-prereqs). Anyway, the question doesn't mention any of them

It should be c as requirement is least operational overhead. Creating 4 lambda functions, event bridge rule, deploying through cloud formation works but adds operational overhead

Option C, which involves using AWS Systems Manager State Manager to start and stop the RDS instances, is indeed a viable solution. It allows you to automate the process of keeping your RDS instances in a desired state, such as starting and stopping them on a schedule12. However, the reason Option D (using Amazon EventBridge with AWS Lambda) might be preferred for this scenario is due to its simplicity and flexibility. EventBridge rules can be easily configured with cron expressions to trigger Lambda functions, which can start and stop the RDS instances. This setup typically involves fewer steps and less configuration compared to setting up State Manager associations and IAM roles3. Both options are valid, but Option D generally offers a more straightforward approach with potentially lower operational overhead