A financial company has an application deployed in an AWS Auto Scaling Group. In most cases, the application`s traffic is very stable, and the ASG does not scale in or out. However, since the latest release last week, EC2 instances may fail the health check in Elastic Load Balancer and then be terminated by ASG. The development team has created an ASG lifecycle hook to access the instance and troubleshoot the issue. After the instance goes to the state of “Terminating:Wait”, which AWS service can be configured to receive a notification automatically? (Select TWO.) 

Answer options:

A.AWS CloudTrail
B.AWS Config
C.AWS CloudWatch Event
D.AWS SNS
E.AWS Step Functions

Correct Answer – C, D
Auto Scaling lifecycle hook has provided users a chance to suspend the scaling process. The lifecycle hook state is illustrated as below:
When the instance goes to the Wait status, several AWS services can receive a notification. Check details in
https://docs.aws.amazon.com/autoscaling/ec2/userguide/lifecycle-hooks.html#preparing-for-notification.
Option C is CORRECT: Because CloudWatch Event is the recommended service to receive notifications when an event happens:
By registering a target such as Lambda, it is very convenient to customize an alert to notify the team for this event.
Option Dis CORRECT: Because SNS can be added as a notification target in AWS CLI command put-lifecycle-hook with the option of --notification-target-arn. The ARN of the notification target in --notification-target-arn can be either an SQS queue or an SNS topic, according to
https://docs.aws.amazon.com/cli/latest/reference/autoscaling/put-lifecycle-hook.html.
Option A, B, Eare incorrect: Because these services are unsupported to receive notifications for ASG lifecycle hooks.