Ensure there is an Amazon CloudWatch alarm available in your AWS account that is triggered each time an AWS EC2 instance configuration and status change is made. This CloudWatch alarm must fire every time an AWS API call is performed to create, terminate, start, stop or reboot an EC2 instance.
Using Amazon CloudWatch alarms to detect EC2 instance configuration and status changes will help you stay up-to-date on the resource availability, gain insights into auto-scaling lifecycle, mitigate downtime, prevent data loss or avoid unexpected charges on your AWS bill. Note 1: For this rule Cloud Conformity assumes that the CloudTrail service is already enabled to stream event log data to CloudWatch within your AWS account, otherwise see this rule to enable AWS Cloudtrail – CloudWatch integration.
Note 2: You have also the option to implement this conformity rule with AWS CloudFormation. Download the required CloudFormation template from this URL and follow the AWS instructions available here.
Step 1: Create a Simple Notification Service (SNS) topic and the necessary subscription to send email notifications whenever the appropriate Amazon CloudWatch alarm is triggered.
Step 2: Create the necessary metric filter and the CloudWatch alarm that will fire and send email notifications whenever an AWS EC2 instance configuration/status will change.