You need to implement Blue/Green Deployment for several multi-tier web applications. Each of them has Its Individual infrastructure:<br>
Amazon Elastic Compute Cloud (EC2) front-end servers, Amazon ElastiCache clusters, Amazon Simple Queue Service<br>
(SQS) queues, and Amazon Relational Database (RDS) Instances.<br>
Which combination of services would give you the ability to distribute the traffic between different deployed versions of your application?

Answer options:

A.Create one AWS Elastic Beanstalk application and all AWS resources (using configuration files inside the application source bundle) for each web application. New versions would be deployed using Elastic Beanstalk environments and using the Swap URLs feature.
B.Using AWS CloudFormation templates, create one Elastic Beanstalk application and all required AWS resources for each web application.New versions would be deployed using AWS CloudFormation templates to create new Elastic Beanstalk environments. Traffic would be balanced between them using weighted Round Robin (WRR) records in Amazon Route 53.
C.Using AWS CloudFormation templates, create one Elastic Beanstalk application and all required AWS resources for each web application. New versions would be deployed updating a parameter on the CloudFormation template and passing it to the cfn-hup helper daemon. Traffic would be balanced between them using Weighted Round Robin (WRR) records in Amazon Route 53.
D.Create one Elastic Beanstalk application and all AWS resources (using configuration files inside the application source bundle) for each web application. New versions would be deployed updating the Elastic Beanstalk application version for the current Elastic Beanstalk environment.

Answer – B
This an example of Blue-green deployment.
With Amazon Route 53, you can define a percentage of traffic to go to the green environment and gradually update the weights until the green environment carries the full production traffic. A weighted distribution provides the ability to perform canary analysis where a small percentage of production traffic is introduced to a new environment. You can test the new code and monitor for errors, limiting the blast radius if any issues are encountered. It also allows the green environment to scale out to support the full production load if you’re using Elastic Load Balancing.
When it’s time to promote the green environment/stack into production, update DNS records to point to the green environment/stack’s load balancer. You can also do this DNS flip gradually by using the Amazon Route 53 weighted routing policy.
For more information on Blue-green deployment, please refer to the link:
https://d0.awsstatic.com/whitepapers/AWS_Blue_Green_Deployments.pdf
The key of the question is that the approach should be able to control the traffic between different versions of deployments. As a result, Route53 should be considered first among all the answers.