AWS Certified Solutions Architect – Professional SAP-C01 – Question138

An organization is creating a VPC for their application hosting. The organization has created two private subnets in the same AZ and created one subnet in a separate zone. The organization wants to make a HA system with the internal ELB.
Which of these statements is true with respect to an internal ELB in this scenario?

A. ELB can support only one subnet in each availability zone.
B. ELB does not allow subnet selection; instead it will automatically select all the available subnets of the VPC.
C. If the user is creating an internal ELB, he should use only private subnets.
D. ELB can support all the subnets irrespective of their zones.

Correct Answer: A

Explanation:

Explanation: The Amazon Virtual Private Cloud (Amazon VPC) allows the user to define a virtual networking environment in a private, isolated section of the Amazon Web Services (AWS) cloud. The user has complete control over the virtual networking environment. Within this virtual private cloud, the user can launch AWS resources, such as an ELB, and EC2 instances. There are two ELBs available with VPC: internet facing and internal (private) ELB.
For internal servers, such as App servers the organization can create an internal load balancer in their VPC and then place back-end application instances behind the internal load balancer. The internal load balancer will route requests to the back-end application instances, which are also using private IP addresses and only accept requests from the internal load balancer. The Internal ELB supports only one subnet in each AZ and asks the user to select a subnet while configuring internal ELB.
Reference:
http://docs.aws.amazon.com/ElasticLoadBalancing/latest/DeveloperGui…