AWS Certified Advanced Networking – Specialty ANS-C00 – Question133

A user is running a batch process on EBS backed EC2 instances. The batch process launches few EC2 instances to process hadoop Map reduce jobs which can run between 50-600 minutes or sometimes for even more time. The user wants a configuration that can terminate the instance only when the process is completed. How can the user configure this with CloudWatch?

A. Configure a job which terminates all instances after 600 minutes
B. It is not possible to terminate instances automatically
C. Set up the CloudWatch with Auto Scaling to terminate all the instances
D. Configure the CloudWatch action to terminate the instance when the CPU utilization falls below 5%

Correct Answer: D

Explanation:

Explanation:
Amazon CloudWatch alarm watches a single metric over a time period that the user specifies and performs one or more actions based on the value of the metric relative to a given threshold over a number of time periods. The user can setup an action which terminates the instances when their CPU utilization is below a certain threshold for a certain period of time. The EC2 action can either terminate or stop the instance as part of the EC2 action.
Reference: http://docs.aws.amazon.com/AmazonCloudWatch/latest/DeveloperGuide/UsingAlarmActions.html