AWS Certified Solutions Architect – Professional — Question 617

A financial services company in North America plans to release a new online web application to its customers on AWS. The company will launch the application in the us-east-1 Region on Amazon EC2 instances. The application must be highly available and must dynamically scale to meet user traffic. The company also wants to implement a disaster recovery environment for the application in the us-west-1 Region by using active-passive failover.
Which solution will meet these requirements?

Answer options

• A. Create a VPC in us-east-1 and a VPC in us-west-1. Configure VPC peering. In the us-east-1 VPC, create an Application Load Balancer (ALB) that extends across multiple Availability Zones in both VPCs. Create an Auto Scaling group that deploys the EC2 instances across the multiple Availability Zones in both VPCs. Place the Auto Scaling group behind the ALB.
• B. Create a VPC in us-east-1 and a VPC in us-west-1. In the us-east-1 VPC, create an Application Load Balancer (ALB) that extends across multiple Availability Zones in that VPC. Create an Auto Scaling group that deploys the EC2 instances across the multiple Availability Zones in the us-east-1 VPC. Place the Auto Scaling group behind the ALB. Set up the same configuration in the us-west-1 VPC. Create an Amazon Route 53 hosted zone. Create separate records for each ALB. Enable health checks to ensure high availability between Regions.
• C. Create a VPC in us-east-1 and a VPC in us-west-1. In the us-east-1 VPC, create an Application Load Balancer (ALB) that extends across multiple Availability Zones in that VPC. Create an Auto Scaling group that deploys the EC2 instances across the multiple Availability Zones in the us-east-1 VPC. Place the Auto Scaling group behind the ALB. Set up the same configuration in the us-west-1 VPC. Create an Amazon Route 53 hosted zone. Create separate records for each ALB. Enable health checks and configure a failover routing policy for each record.
• D. Create a VPC in us-east-1 and a VPC in us-west-1. Configure VPC peering. In the us-east-1 VPC, create an Application Load Balancer (ALB) that extends across multiple Availability Zones in both VPCs. Create an Auto Scaling group that deploys the EC2 instances across the multiple Availability Zones in both VPCs. Place the Auto Scaling group behind the ALB. Create an Amazon Route 53 hosted zone. Create a record for the ALB.

Correct answer: C

Explanation

To achieve an active-passive disaster recovery setup across two AWS Regions, you must deploy independent environments in each Region, including an Application Load Balancer (ALB) and an Auto Scaling group. Amazon Route 53 is then used to manage traffic between these regions by employing a failover routing policy combined with health checks, which automatically redirects traffic to the passive region (us-west-1) if the primary region (us-east-1) becomes unhealthy. Options A and D are incorrect because an ALB and Auto Scaling groups cannot span across different AWS Regions, while Option B is incorrect because it lacks the necessary failover routing policy.