You are developing a Java application that is deployed in AWS by an Auto Scaling Group. The EC2 instances belong to the m5.large type. Recently, due to several newly added features, the response time of the application increased because of the high CPU usage rate. You need to modify the EC2 instance type to c5.large to remedy this issue. What is the best way to implement this?

Answer options:

A.In AWS console, edit the Auto Scaling Group by modifying the instance type from m5.large to c5.large.
B.Select the relevant launch configuration and choose “Actions -> Copy launch configuration”. Modify the instance type accordingly in the new configuration. Select the new launch configuration for the Auto Scaling Group.
C.In AWS EC2 console, stop the EC2 instances, modify the instance type to c5.large in “Instance Settings -> Change Instance Type” and then start the instances.
D.Select the Auto Scaling launch configuration and choose “Actions -> Change Instance Type”. Modify the instance type to c5.large accordingly.

Correct Answer – B
One main feature for Auto Scaling configuration is that it cannot be modified after being created. To change the launch configuration, the best practice is to use an existing one as the basis for a new configuration and then update the ASG to use the new one.
Option A is incorrect: Because the instance type belongs to the domain of launch configuration rather than Auto Scaling Group itself.
Option B is CORRECT: Because the user can select the existing configuration, copy it to a new one, and then modify the instance type. With this approach, the user does not need to configure everything from scratch.
Refer to https://docs.aws.amazon.com/autoscaling/ec2/userguide/change-launch-config.html for more details.
Option C is incorrect: Because this approach only works temporarily. After the instance is terminated, ASG still uses the m5.large instance type for any new instances.
Option D is incorrect: Because existing Auto Scaling launch configurations cannot be modified.