AWS Certified Solutions Architect – Professional — Question 930

Someone is creating a VPC for their application hosting. He has created two private subnets in the same availability zone and created one subnet in a separate availability zone. He wants to make a High Availability system with an internal Elastic Load Balancer.
Which choice is true regarding internal ELBs in this scenario? (Choose two.)

Answer options

• A. Internal ELBs should only be launched within private subnets.
• B. Amazon ELB service does not allow subnet selection; instead it will automatically select all the available subnets of the VPC.
• C. Internal ELBs can support only one subnet in each availability zone.
• D. An internal ELB can support all the subnets irrespective of their zones.

Correct answer: A, C

Explanation

An internal Elastic Load Balancer (ELB) routes traffic to targets with private IP addresses and should be launched within private subnets. Furthermore, AWS restricts ELB configurations to a maximum of one subnet per Availability Zone, which prevents associating multiple subnets from the same AZ with a single load balancer.