AWS Certified Solutions Architect – Professional — Question 797

An organization is hosting a scalable web application using AWS. The organization has configured ELB and Auto Scaling to make the application scalable.
Which of the below mentioned statements is not required to be followed for ELB when the application is planning to host a web application on VPC?

Answer options

• A. The ELB and all the instances should be in the same subnet.
• B. Configure the security group rules and network ACLs to allow traffic to be routed between the subnets in the VPC.
• C. The internet facing ELB should have a route table associated with the internet gateway.
• D. The internet facing ELB should be only in a public subnet.

Correct answer: A

Explanation

An ELB does not require its registered instances to reside in the exact same subnet as the load balancer; they can be distributed across different subnets and Availability Zones for high availability. However, an internet-facing ELB must be placed in a public subnet with a route to an internet gateway, and appropriate security group and network ACL rules must be configured to allow traffic flow.