AWS Certified Solutions Architect – Associate (SAA-C03) — Question 130

A solutions architect needs to help a company optimize the cost of running an application on AWS. The application will use Amazon EC2 instances, AWS Fargate, and AWS Lambda for compute within the architecture.
The EC2 instances will run the data ingestion layer of the application. EC2 usage will be sporadic and unpredictable. Workloads that run on EC2 instances can be interrupted at any time. The application front end will run on Fargate, and Lambda will serve the API layer. The front-end utilization and API layer utilization will be predictable over the course of the next year.
Which combination of purchasing options will provide the MOST cost-effective solution for hosting this application? (Choose two.)

Answer options

• A. Use Spot Instances for the data ingestion layer
• B. Use On-Demand Instances for the data ingestion layer
• C. Purchase a 1-year Compute Savings Plan for the front end and API layer.
• D. Purchase 1-year All Upfront Reserved instances for the data ingestion layer.
• E. Purchase a 1-year EC2 instance Savings Plan for the front end and API layer.

Correct answer: A, C

Explanation

Choosing Spot Instances for the data ingestion layer is the most cost-effective option due to the unpredictable nature of the workloads, as Spot Instances are significantly cheaper than On-Demand Instances. Additionally, a 1-year Compute Savings Plan for the front end and API layers provides cost savings for predictable usage, making it the best choice. The other options are either more expensive or not suitable for sporadic workloads.