Your company currently has a set of EC2 Instances hosted on the AWS Cloud. There is a requirement to ensure the restart of instances if a CloudWatch metric goes beyond a certain threshold. As a solutions architect, how would you ask the IT admin staff to implement this?

Answer options:

A.Look at the Cloudtrail logs for events and then restart the Instance based on the events.
B.Create a CloudWatch metric which looks into the instance threshold, and assign this metric against an alarm to reboot the instance.
C.Create a CLI script that restarts the server at certain intervals.
D.Use the AWS Config utility on the EC2 Instance to check for metrics and restart the server.

Answer – B
The AWS Documentation mentions the following.
Using Amazon CloudWatch alarm actions, you can create alarms that automatically stop, terminate, reboot, or recover your EC2 instances. You can use the stop or terminate actions to help you save money when you no longer need an instance to be running. You can use the reboot and recover actions to automatically reboot those instances or recover them onto new hardware if a system impairment occurs.
Option A is incorrect because CloudTrail logs will provide event details and not metrics.
Option C is incorrect because we want to restart Instance as we reach a certain threshold. But this way, it will keep on restarting the Instance even without any threshold reach.
Option D is incorrect because AWS Config is a service that enables you to assess, audit, and evaluate the configurations of your AWS resources.
For more information on using alarm actions, please visit the URL-
https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/UsingAlarmActions.html