You have an EC2 instance that provides a central file-sharing service to your customers. You want a mechanism to recover the instance if it becomes impaired automatically. For example, if there are software issues on the physical host for instance and the system status check fails, you should get a notification and actions should be taken automatically to attempt to recover the instance. Which method is the best one for you to take?

Answer options:

A.Create a CloudWatch alarm to monitor the Amazon EC2 instance. When the instance becomes impaired, trigger an SNS notification and automatically recover the instance.
B.Add the instance to an Auto Scaling group so that the ASG can automatically add a new instance when the system status check fails.
C.Create a CloudWatch Event rule to monitor the EC2 instance state. When the instance is stopped or terminated, trigger an SNS notification and a Lambda function to recover the instance automatically.
D.Configure the instance using an Auto Scaling group. Create a CloudWatch alarm to monitor the EC2 instance status. If the instance fails the status check, inform the Auto Scaling group to launch a new instance to replace the original one.

Correct Answer – A
Check the below references for how to automatically recover an EC2 instance:
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/UsingAlarmActions.html#AddingRecoverActions,
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-recover.html.
Option A is CORRECT: Because you can configure a CloudWatch alarm to recover the instance if it fails the status check. Take the below screenshot as an example:
Option B is incorrect: Because you should not create a new instance since the question asks for recovering the instance.
Option C is incorrect: Because you have to maintain a Lambda function. This option is not as straightforward as option A.Option D is incorrect: Similar to Option
B. What the ASG does is creating a new instance rather than attempting to recover it.