AWS Certified Solutions Architect – Professional SAP-C01 – Question352

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.)

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: AC

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 elastic load balancers, 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…