AWS Certified DevOps Engineer – Professional — Question 8

An online company uses Amazon EC2 Auto Scaling extensively to provide an excellent customer experience while minimizing the number of running EC2 instances. The company's self-hosted Puppet environment in the application layer manages the configuration of the instances. The IT manager wants the lowest licensing costs and wants to ensure that whenever the EC2 Auto Scaling group scales down, removed EC2 instances are deregistered from the Puppet master as soon as possible.
How can the requirement be met?

Answer options

• A. At instance launch time, use EC2 user data to deploy the AWS CodeDeploy agent. Use CodeDeploy to install the Puppet agent. When the Auto Scaling group scales out, run a script to register the newly deployed instances to the Puppet master. When the Auto Scaling group scales in, use the EC2 Auto Scaling EC2_INSTANCE_TERMINATING lifecycle hook to trigger de-registration from the Puppet master.
• B. Bake the AWS CodeDeploy agent into the base AMI. When the Auto Scaling group scales out, use CodeDeploy to install the Puppet agent, and execute a script to register the newly deployed instances to the Puppet master. When the Auto Scaling group scales in, use the CodeDeploy ApplicationStop lifecycle hook to run a script to de-register the instance from the Puppet master.
• C. At instance launch time, use EC2 user data to deploy the AWS CodeDeploy agent. When the Auto Scaling group scales out, use CodeDeploy to install the Puppet agent, and run a script to register the newly deployed instances to the Puppet master. When the Auto Scaling group scales in, use the EC2 user data instance stop script to run a script to de-register the instance from the Puppet master.
• D. Bake the AWS Systems Manager agent into the base AMI. When the Auto Scaling group scales out, use the AWS Systems Manager to install the Puppet agent, and run a script to register the newly deployed instances to the Puppet master. When the Auto Scaling group scales in, use the Systems Manager instance stop lifecycle hook to run a script to de-register the instance from the Puppet master.

Correct answer: A

Explanation

Option A is correct because it utilizes the EC2_INSTANCE_TERMINATING lifecycle hook, which ensures that deregistration from the Puppet master occurs immediately when instances are terminated. Option B is incorrect as it relies on the CodeDeploy ApplicationStop lifecycle hook, which is not as timely for deregistration. Option C uses EC2 user data for scaling in, which may not trigger deregistration promptly. Option D incorrectly suggests using the AWS Systems Manager agent, which is not the specified requirement for managing the Puppet environment.