AWS Certified Solutions Architect – Professional (SAP-C02) — Question 515

A company migrated to AWS and uses AWS Business Support. The company wants to monitor the cost-effectiveness of Amazon EC2 instances across AWS accounts. The EC2 instances have tags for department, business unit, and environment. Development EC2 instances have high cost but low utilization.

The company needs to detect and stop any underutilized development EC2 instances. Instances are underutilized if they had 10% or less average daily CPU utilization and 5 MB or less network I/O for at least 4 of the past 14 days.

Which solution will meet these requirements with the LEAST operational overhead?

Answer options

• A. Configure Amazon CloudWatch dashboards to monitor EC2 instance utilization based on tags for department, business unit, and environment. Create an Amazon EventBridge rule that invokes an AWS Lambda function to stop underutilized development EC2 instances.
• B. Configure AWS Systems Manager to track EC2 instance utilization and report underutilized instances to Amazon CloudWatch. Filter the CloudWatch data by tags for department, business unit, and environment. Create an Amazon EventBridge rule that invokes an AWS Lambda function to stop underutilized development EC2 instances.
• C. Create an Amazon EventBridge rule to detect low utilization of EC2 instances reported by AWS Trusted Advisor. Configure the rule to invoke an AWS Lambda function that filters the data by tags for department, business unit, and environment and stops underutilized development EC2 instances.
• D. Create an AWS Lambda function to run daily to retrieve utilization data for all EC2 instances. Save the data to an Amazon DynamoDB table. Create an Amazon QuickSight dashboard that uses the DynamoDB table as a data source to identify and stop underutilized development EC2 instances.

Correct answer: C

Explanation

AWS Trusted Advisor includes a built-in 'Low Utilization Amazon EC2 Instances' check that uses the exact criteria specified (10% or less CPU and 5 MB or less network I/O for at least 4 of the past 14 days). Because the company has AWS Business Support, they have access to this check and can use Amazon EventBridge to detect status changes and trigger an AWS Lambda function to stop the tagged instances automatically. Other solutions require building custom monitoring dashboards, agent configurations, or database pipelines, which significantly increase operational overhead.