Exam AWS DevOps Engineer Professional topic 1 question 197 discussion

A you say?

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-attribute-updatepolicy.html

A is the best

Option B is incorrect because it suggests using AWS CodeDeploy to perform an in-place deployment type, which is not appropriate for replacing EC2 instances in batches. Option C is incorrect because it suggests using AWS CodeDeploy to perform a blue/green deployment type, which is not appropriate for replacing EC2 instances in batches. Option D is incorrect because it suggests using a StackPolicy to control the update, which is not appropriate for this use case.

Option A is the correct solution. It involves modifying the CloudFormation template to include an UpdatePolicy attribute for the Auto Scaling group with the AutoScalingRollingUpdate policy. This policy allows for rolling updates that replace instances in batches of a specified size, which in this case is two instances at a time. The MinInstancesInService attribute ensures that a minimum of four instances are running whenever an update is in progress. To update the software, either the ImageId or UserData of the AWS::EC2::LaunchTemplate is altered and the stack is updated.