AWS Certified Advanced Networking – Specialty (ANS-C00) — Question 43

A bank built a new version of its banking application in AWS using containers that connect to an on-premises database over a VPN connection. This application version requires users to also update their client application. The bank plans to deprecate the earlier client version. However, the company wants to keep supporting earlier clients through their on-premises version of the application to serve a small portion of the customers who haven't yet upgraded.
What design will allow the company to serve both newer and earlier clients in the MOST efficient way?

Answer options

• A. Use an Amazon Route 53 multivalue answer routing policy to route older client traffic to the on-premises application version and the rest of the traffic to the new AWS based version.
• B. Use a Classic Load Balancer for the new application. Route all traffic to the new application by using an Elastic Load Balancing (ELB) load balancer DNS. Define a user-agent-based rule on the backend servers to redirect earlier clients to the on-premises application.
• C. Use an Application Load Balancer for the new application. Register both the new and earlier applications as separate target groups and use path-based routing to route traffic based on the application version.
• D. Use an Application Load Balancer for the new application. Register both the new and earlier application backends as separate target groups. Use host header- based routing to route traffic based on the application version.

Correct answer: B

Explanation

Option B is correct because it efficiently uses a Classic Load Balancer to manage traffic, ensuring older clients are redirected to the on-premises application without any disruption. The other options either do not effectively separate the traffic for older clients or do not utilize the most suitable load balancing strategies for this scenario.