Reserved instance subscriptions for EC2 and RDS

[ediededi]

I am subscribed to the “AWS Certified Solutions Architect Associate Practice Exams SAA-C03 2024”, and in one of the questions, I think the right answer should be “Purchase reserved instance subscriptions for EC2 and RDS”, since :

1 : “Deploy the CloudFormation template of the Instance Scheduler on AWS” means a potential lost of data every time

2: AWS offers scheduled reserved instances by hours and days of the week, so you can choose from 9-5 on weeks day as you can see from the attached picture:

For reference, this is the question with the answers from TD:

A company runs an internal application on AWS which uses EC2 instances for compute and Amazon RDS for PostgreSQL for its data store. Considering the application only runs during working hours on weekdays, a solution is required to optimize costs with minimal operational overhead.

Which solution would satisfy these requirements?

• Purchase reserved instance subscriptions for EC2 and RDS
• Create a CloudWatch alarm that triggers a Lambda function when CPU utilization falls below an idle threshold. In the function, implement logic for stopping both the EC2 instance and the RDS database.
• Purchase a compute savings plan for EC2 and RDS.
• Deploy the CloudFormation template of the Instance Scheduler on AWS. Set up the start and stop schedules of the EC2 instance and RDS DB instance.

[Neil-TutorialsDojo]

Hello ediededi,

Good day!

The concern about potential data loss when using the “Instance Scheduler on AWS” is understandable but can be mitigated with proper configuration. The Instance Scheduler stops and starts EC2 and RDS instances based on a predefined schedule. If the application is gracefully shut down before stopping instances and the data is properly saved, there should be no risk of data loss. Additionally, RDS instances maintain automated backups and snapshots, which further protect against data loss.

Scheduled Reserved Instances were indeed an alternative for specific, predictable workloads. However, it’s important to note that Scheduled Reserved Instances are no longer available in AWS. For further details, refer to this documentation. https://aws.amazon.com/blogs/aws/new-scheduled-reserved-instances/ and the attached screenshot.
Thus, the best approach for this scenario remains using the Instance Scheduler on AWS to optimize costs while ensuring the application runs during the required hours with minimal operational overhead.

I hope this answers your question. Feel free to reach out if you have any further questions or need additional assistance!

Regards,
Neil @ Tutorials Dojo

[ediededi]

Thank you for your reply and for the heads up regarding the discontinuation of “Scheduled Reserved Instances”