https://aws.amazon.com/blogs/database/schedule-amazon-rds-stop-and-start-using-aws-lambda/ It is option D. Option A could have been applicable had it been AWS Systems Manager State Manager & not AWS Systems Manager Session Manager

A is true for sure. "Schedule Amazon RDS stop and start using AWS Systems Manager" Steps in the documentation: 1. Configure an AWS Identity and Access Management (IAM) policy for State Manager. 2. Create an IAM role for the new policy. 3. Update the trust relationship of the role so Systems Manager can use it. 4. Set up the automatic stop with State Manager. 5. Set up the automatic start with State Manager. https://aws.amazon.com/blogs/database/schedule-amazon-rds-stop-and-start-using-aws-systems-manager/

D. You need to use AWS Systems Manager State Manager, not Systems Manager Session Manager.

Agree with study_aws1 comment. Lambda and event bridge solution is the correct answer. The option A was only possible if it had mentioned System manager state manager

we still pay for RDS even when the instance stops. So for cost-optimize -> C

Although both A and D is a workable solution, the requirements is to minimum cost. The benefits of automating the startup and shutdown of RDS DB instances using Lambda allows organizations to further reduce compute costs and simplify the administration of database environments that don’t need to be running continuously. https://aws.amazon.com/blogs/database/schedule-amazon-rds-stop-and-start-using-aws-lambda/ For using system manager to accomplish the task works however keep in mind that although we’re stopping the databases, the storage costs for the databases still apply. https://aws.amazon.com/blogs/database/schedule-amazon-rds-stop-and-start-using-aws-systems-manager/ Initially I also thought that A would be the correct answer however looking at the administration and cost I would go for D as a better solution instead.

To automatically shutdown an RDS instance during 09:00 PM to 09:00 AM and have it available between 09:00 AM to 09:00 PM, you can use AWS Systems Manager Maintenance Windows. Create two Maintenance Windows - one to stop the RDS instance at 09:00 PM and another to start it at 09:00 AM. For each Maintenance Window, select the "AWS-StopRDSInstance" and "AWS-StartRDSInstance" runbooks respectively and specify the cron expression for the schedule. Tag the RDS instance with a name so it can be identified by the runbooks. The runbooks will then automatically stop and start the RDS instance on the specified schedule without needing any manual intervention.

Guys, we still have to pay for RDS instance even we stopped it, isn't it?

AWS Lambda functions can be used to start and stop RDS instances programmatically. EventBridge scheduled rules can trigger the Lambda functions at specified times daily. This allows fully automating the starting and stopping of RDS on a schedule to match usage patterns. RDS billing is per hour when instance is running, so stopping when not in use significantly reduces costs. Using Lambda and EventBridge is simpler and more robust than cron jobs on EC2. ElastiCache and Systems Manager Session Manager are useful tools but do not directly address scheduled RDS start/stop.

You can use AWS Lambda and Amazon EventBridge to schedule a Lambda function to stop and start the idle databases with specific tags to save on compute costs. https://aws.amazon.com/blogs/database/schedule-amazon-rds-stop-and-start-using-aws-lambda/#:~:text=you%20to%20schedule%20a-,Lambda%20function,-to%20stop%20and%20start

Here is the recommended solutions which describes choice D - https://aws.amazon.com/blogs/database/save-costs-by-automating-the-start-and-stop-of-amazon-rds-instances-with-aws-lambda-and-amazon-eventbridge/

AWS Lambda functions can be used to start and stop RDS instances programmatically. EventBridge scheduled rules can trigger the Lambda functions at specified times daily. This allows fully automating the starting and stopping of RDS on a schedule to match usage patterns. RDS billing is per hour when instance is running, so stopping when not in use significantly reduces costs. Using Lambda and EventBridge is simpler and more robust than cron jobs on EC2. ElastiCache and Systems Manager Session Manager are useful tools but do not directly address scheduled RDS start/stop.

By using AWS Lambda functions triggered by Amazon EventBridge scheduled rules, the company can automate the start and stop actions for the Amazon RDS for MySQL DB instance based on the 12-hour access period. This allows them to minimize costs by only running the DB instance when it is needed. Option A is not the most suitable solution because it refers to IAM policies for AWS Systems Manager Session Manager, which is primarily used for interactive shell access to EC2 instances and does not directly address the requirement of starting and stopping the DB instance. Option B is not the most suitable solution because it suggests using Amazon ElastiCache for Redis as a cache cluster, which may not provide the desired cost optimization for the DB instance. Option C is not the most suitable solution because launching an EC2 instance and configuring cron jobs to start and stop it does not directly address the requirement of minimizing costs for the Amazon RDS DB instance.

I got this question in real exam!

State Manager, a capability of AWS Systems Manager

Option D is correct

In a typical development environment, dev and test databases are mostly utilized for 8 hours a day and sit idle when not in use. However, the databases are billed for the compute and storage costs during this idle time. To reduce the overall cost, Amazon RDS allows instances to be stopped temporarily. While the instance is stopped, you’re charged for storage and backups, but not for the DB instance hours. Please note that a stopped instance will automatically be started after 7 days. This post presents a solution using AWS Lambda and Amazon EventBridge that allows you to schedule a Lambda function to stop and start the idle databases with specific tags to save on compute costs. The second post presents a solution that accomplishes stop and start of the idle Amazon RDS databases using AWS Systems Manager.