Exam AWS-SysOps topic 1 question 784 discussion

C. Use an Amazon Route 53 weighted routing policy to gradually move traffic from the old version to the new one

A option. because Route53 point to ALB and the old scaling group is in the ALB, you can change your auto scaling group there and gradually when new instances are created use the new launch configuration

To gradually shift traffic to the new version of the web application running on EC2 instances behind an Application Load Balancer (ALB) and EC2 Auto Scaling group, you can use Amazon Route 53's weighted routing policy.

I vote C

Let's first eliminate Wrong answers: A. Create an Auto Scaling target tracking scaling policy ...WRONG...target tracking is a parameter in ASG that determines WHEN to scale in or out your ASG....Therefore complete irrelevant here. | B. Change the Application Load Balancer to a Network Load Balancer...WRONG..we're talking about ALB here..NLB this is WRONG... | D. Deploy Amazon Redshift ...WRONG ....Irrelevant and silly. | Without even reading it, C is the correct answer. C. Use an Amazon Route 53 weighted routing policy to gradually move traffic from the old version to the new one But another way to reason it. the ratio of load balancing is typically managed using Route 53 weighted routing. https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy.html#routing-policy-weighted

I think it might be A based on the links I referred to below. However, I don't really understand what does the "Auto Scaling target tracking scaling policy" mean here in the answer A and that was the reason I feel a bit not so sure if A is correct or not. Swap the Auto Scaling Group Behind Elastic Load Balancer https://docs.aws.amazon.com/whitepapers/latest/blue-green-deployments/swap-the-auto-scaling-group-behind-elastic-load-balancer.html New – Application Load Balancer Simplifies Deployment with Weighted Target Groups https://aws.amazon.com/blogs/aws/new-application-load-balancer-simplifies-deployment-with-weighted-target-groups/

Answer is here : https://aws.amazon.com/blogs/aws/new-application-load-balancer-simplifies-deployment-with-weighted-target-groups/ Route53 points out to an ELB (not to a specific target group) Answer is A.

C https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy.html#routing-policy-weighted

C is the Answer R53 weighted policy can be used to gradually move traffic from the old to the new version.

The answer is A Check solution called "Swap the Auto Scaling Group Behind Elastic Load Balancer" This will help swap old auto scaling group to new version of auto scaling group behind an ELB https://docs.aws.amazon.com/whitepapers/latest/blue-green-deployments/swap-the-auto-scaling-group-behind-elastic-load-balancer.html

Wouldn't "B" be a solution?, changing it to NLB and adding both ASG with routing would solve it!

I'll go with A

Just to eliminate B - there is option for ALB to weighted balance between more target groups. https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-listeners.html#forward-actions But B is about change from ALB to NLB. So definitely not B.

A. Create an Auto Scaling target tracking scaling policy to gradually move traffic from the old version to the new one

"Amazon Route 53 is used for DNS and points to the load balancer"

C is correct Target Tracking will just ensure that the auto scaling level is consistent based on a metric. R53 will route traffic to the ALB (Important to note that they mentioned an ALB and not just ELB). From there it is assumed that some form of path based routing will occur. Again, I could be wrong, but this is my observation

A. Route 53 does not send direct traffic to auto scaling group