ANS-C01 Question 71
Select 2A company is hosting a multi-tier web application on AWS. The application includes a front-end layer that needs to be accessible from the internet, and a back-end layer that must only communicate with internal services. The company wants to use Elastic Load Balancers (ELBs) for distributing traffic. Which combination of ELB types should the company use to meet the requirements?
- A
Use an Application Load Balancer (ALB) configured as an internet-facing load balancer for the front-end layer.
- B
Use a Network Load Balancer (NLB) configured as an internet-facing load balancer for the back-end layer.
- C
Use an Application Load Balancer (ALB) configured as an internal load balancer for the back-end layer.
- D
Use a Network Load Balancer (NLB) configured as an internal load balancer for the back-end layer.
- E
Use an Application Load Balancer (ALB) configured as an internal load balancer for the front-end layer.
Show answer and explanation
Correct answers: A, C
Explanation
To meet the requirements of the scenario, the front-end layer needs an internet-facing load balancer to handle public traffic, making an Application Load Balancer (ALB) the right choice due to its HTTP/HTTPS support and ability to route based on content. The back-end layer requires an internal load balancer to restrict access to internal services, and an internal ALB is the correct choice for handling HTTP/HTTPS traffic within the VPC.
- A. Correct.
Correct. An internet-facing ALB is suitable for the front-end layer as it can handle HTTP/HTTPS traffic and is accessible from the internet.
- B. Incorrect.
Incorrect. A Network Load Balancer (NLB) configured as internet-facing is not suitable for the back-end layer since the back-end layer should only communicate internally.
- C. Correct.
Correct. An internal ALB is appropriate for the back-end layer as it only accepts traffic from internal resources and can handle HTTP/HTTPS traffic.
- D. Incorrect.
Incorrect. While an NLB can serve as an internal load balancer, it is typically used for TCP/UDP traffic, which is not specified as a requirement for the back-end layer in this scenario.
- E. Incorrect.
Incorrect. An internal ALB for the front-end layer would restrict internet access, which conflicts with the requirement for the front-end layer to be accessible from the internet.