ANS-C01 Question 231
Select 2You are designing a highly available web application in AWS that spans two Availability Zones within the same VPC. The application requires private communication between its instances and must not be exposed to the public internet. You also want to implement a solution to handle failover seamlessly across Availability Zones. Which combination of networking services or configurations will meet these requirements?
- A
Use an Elastic Load Balancer with private subnets in both Availability Zones.
- B
Deploy an Internet Gateway to enable communication between instances in the Availability Zones.
- C
Create a VPC Peering connection between the private subnets in both Availability Zones.
- D
Set up route tables to ensure that traffic within the VPC is routed correctly between the subnets in both Availability Zones.
- E
Enable VPC Flow Logs to monitor network traffic between the instances.
Show answer and explanation
Correct answers: A, D
Explanation
To achieve high availability and private communication between instances in multiple Availability Zones, you need to use an Elastic Load Balancer placed in private subnets and configure route tables to route traffic correctly. An Internet Gateway is unnecessary since the application does not require public internet access, and VPC Peering is not applicable because the subnets are within the same VPC. VPC Flow Logs are optional for monitoring but do not directly address the requirements.
- A. Correct.
This is correct. An Elastic Load Balancer (ELB) in private subnets can distribute traffic between instances across Availability Zones while keeping the communication private.
- B. Incorrect.
This is incorrect. An Internet Gateway is used for internet communication, which is not needed in this scenario since the communication must remain private.
- C. Incorrect.
This is incorrect. A VPC Peering connection is used for communication between two VPCs, not for communication between subnets in the same VPC.
- D. Correct.
This is correct. Proper routing ensures traffic can flow seamlessly between subnets in different Availability Zones within the same VPC.
- E. Incorrect.
This is incorrect. While VPC Flow Logs are useful for monitoring traffic, they do not contribute to the failover or private communication requirements of the application.