How can this be accomplished?

A web application runs on Amazon EC2 instances behind an ELB Application Load Balancer. The instances run in an EC2 Auto Scaling group across multiple Availability Zones. Amazon Route 53 is used for DNS and points to the load balancer. A SysOps Administrator has launched a new Auto Scaling group with a new version of the application, and wants to gradually shift traffic to the new version.

How can this be accomplished?
A . Create an Auto Scaling target tracking scaling policy to gradually move traffic the old version to the new one
B . Change the Application Load Balancer to a Network Load Balancer, then add both Auto Scaling groups as targets
C . Use an Amazon Route 53 weighted routing policy to gradually move traffic from the old version to the new one
D . Deploy Amazon Redshift to gradually move traffic from the old version to the new one using a set of predefined values

View Answer

Answer: A

Reference: https://github.com/aws/containers-roadmap/issues/76