AWS Certified Solutions Architect – Professional — Question 20

A Solutions Architect is designing a highly available and reliable solution for a cluster of Amazon EC2 instances.
The Solutions Architect must ensure that any EC2 instance within the cluster recovers automatically after a system failure. The solution must ensure that the recovered instance maintains the same IP address.
How can these requirements be met?

Answer options

• A. Create an AWS Lambda script to restart any EC2 instances that shut down unexpectedly.
• B. Create an Auto Scaling group for each EC2 instance that has a minimum and maximum size of 1.
• C. Create a new t2.micro instance to monitor the cluster instances. Configure the t2.micro instance to issue an aws ec2 reboot-instances command upon failure.
• D. Create an Amazon CloudWatch alarm for the StatusCheckFailed_System metric, and then configure an EC2 action to recover the instance.

Correct answer: D

Explanation

The correct answer is D because it utilizes Amazon CloudWatch to monitor the health of the EC2 instances and automatically recover them when a failure is detected, maintaining the original IP address. Option A does not provide automatic recovery; it merely restarts instances without monitoring their health. Option B creates Auto Scaling groups which do not guarantee the same IP address upon recovery. Option C involves monitoring from a separate instance, which adds unnecessary complexity and does not ensure automatic recovery.