AWS Certified SysOps Administrator – Associate — Question 161

A web application runs on Amazon EC2 instances behind an Application Load Balancer (ALB). The instances run in an Auto Scaling group across multiple Availability Zones. A SysOps administrator notices that some of these EC2 instances show up as healthy in the Auto Scaling group but show up as unhealthy in the ALB target group.

What is a possible reason for this issue?

Answer options

• A. Security groups are not allowing traffic between the ALB and the failing EC2 instances.
• B. The Auto Scaling group health check is configured for EC2 status checks.
• C. The EC2 instances are failing to launch and failing EC2 status checks.
• D. The target group health check is configured with an incorrect port or path.

Correct answer: D

Explanation

The correct answer is D because the target group health check must be correctly configured to ensure it points to the right port and path that the application is using. If the configuration is incorrect, the ALB will mark the instances as unhealthy. Options A, B, and C do not accurately describe the issue related to the ALB target group health assessment.