You have a web application composed of an Auto Scaling group of web servers behind a load balancer. For each new release, you have a new AMI for the Auto Scaling group and you need to deploy it in a controlled manner.

Answer options:

A.Modify the Autoscaling launch configuration with the new AMI. Use the Auto Scaling rolling updates feature to migrate to the new version.
B.Create an Auto Scaling launch configuration with the new AMI. Create an Auto Scaling group with the new launch configuration and register the Auto Scaling group with the same load balancer. Modify the desired capacity of each group to migrate.
C.Create an Autoscaling launch configuration with the new AMI. Attach the new launch configuration to the same Auto Scaling group. Configure the Auto Scaling group to vary the proportion of instances launched from two launch configurations.
D.Create a new load balancer. Create an Auto Scaling group with the new AMI and register instances with the new load balancer. Use Amazon Route53 weighted Round Robin to vary the proportion of requests sent to the load balancers.

Answer - B
Option A is incorrect because you cannot modify an existing launch configuration.
Option B is CORRECT because you can attach the ASG with the new AMI in the same ELB so that you can control the deployment and rollback easily.
Option C is incorrect because you cannot attach two launch configurations in the same Auto Scaling group.
Option D is incorrect because with this option, you have to create a new Load Balancer, which is not as cost-effective as option
B.For more information on AWS Autoscaling Launch Configurations, please visit:
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-as-launchconfig.html