AWS Certified SysOps Administrator – Associate — Question 285

A company runs an application on Amazon EC2 instances behind an Application Load Balancer. The EC2 instances are in an Auto Scaling group. The application sometimes becomes slow and unresponsive. Amazon CloudWatch metrics show that some EC2 instances are experiencing high CPU load.

A SysOps administrator needs to create a CloudWatch dashboard that can automatically display CPU metrics of all the EC2 instances. The metrics must include new instances that are launched as part of the Auto Scaling group.

What should the SysOps administrator do to meet these requirements in the MOST operationally efficient way?

Answer options

• A. Create a CloudWatch dashboard. Use activity notifications from the Auto Scaling group to invoke a custom AWS Lambda function. Use the Lambda function to update the CloudWatch dashboard to monitor the CPUUtilization metric for the new instance IDs.
• B. Create a CloudWatch dashboard. Run a custom script on each EC2 instance to stream the CPU utilization to the dashboard.
• C. Use CloudWatch metrics explorer to filter by the aws:autoscaling:groupName tag and to create a visualization for the CPUUtilization metric. Add the visualization to a CloudWatch dashboard.
• D. Use CloudWatch metrics explorer to filter by instance state and to create a visualization for the CPUUtilization metric. Add the visualization to a CloudWatch dashboard.

Correct answer: C

Explanation

Using CloudWatch metrics explorer to filter by the aws:autoscaling:groupName tag is the most operationally efficient method because it dynamically includes new EC2 instances as they are launched by the Auto Scaling group. Options A and B require custom code, notifications, or scripts, which significantly increases development and maintenance overhead. Option D is incorrect because filtering by instance state would capture all instances in the account in that state rather than restricting the view to the specific Auto Scaling group.