AWS Certified SysOps Administrator – Associate (legacy) — Question 305

An organization has configured Auto Scaling with ELB. One of the instance health check returns the status as Impaired to Auto Scaling. What will Auto Scaling do in this scenario?

Answer options

• A. Perform a health check until cool down before declaring that the instance has failed
• B. Terminate the instance and launch a new instance
• C. Notify the user using SNS for the failed state
• D. Notify ELB to stop sending traffic to the impaired instance

Correct answer: B

Explanation

When an EC2 Auto Scaling group detects that an instance has been marked as impaired or unhealthy by ELB health checks, its automatic response is to terminate that instance and launch a new one to maintain the desired capacity. While ELB will stop sending traffic to the unhealthy instance, the primary role of Auto Scaling in this scenario is the replacement of the instance rather than just sending notifications or waiting for cooldowns.