Question 31
Domain 2: Design for New SolutionsA North American company with headquarters on the East Coast is deploying a new web application running on Amazon EC2 in the us-east-1 Region. The application should dynamically scale to meet user demand and maintain resiliency. Additionally, the application must have disaster recover capabilities in an active-passive configuration with the us-west-1 Region. Which steps should a solutions architect take after creating a VPC in the us-east-1 Region?
Correct answer: B
Explanation
Task 1.3 says to design reliable and resilient architectures and “implement architectures to automatically recover from failure.” An ALB across multiple AZs with an Auto Scaling group provides load balancing and elastic scaling, and duplicating it in us-west-1 with Route 53 failover and health checks supports disaster recovery in an active-passive design.
Why each option is right or wrong
A. Create a VPC in the us-west-1 Region. Use inter-Region VPC peering to connect both VPCs. Deploy an Application Load Balancer (ALB) spanning multiple Availability Zones (AZs) to the VPC in the us-east-1 Region. Deploy EC2 instances across multiple AZs in each Region as part of an Auto Scaling group spanning both VPCs and served by the ALB.
Auto Scaling groups span Availability Zones, not multiple VPCs or Regions.
B. Deploy an Application Load Balancer (ALB) spanning multiple Availability Zones (AZs) to the VPC in the us-east-1 Region. Deploy EC2 instances across multiple AZs as part of an Auto Scaling group served by the ALB. Deploy the same solution to the us-west-1 Region. Create an Amazon Route 53 record set with a failover routing policy and health checks enabled to provide high availability across both Regions.
Task 1.3 in the SAP-C02 guide explicitly calls for designing disaster recovery solutions based on RTO/RPO and implementing architectures that automatically recover from failure. An ALB deployed across multiple AZs with an Auto Scaling group removes the single-AZ failure point and provides elastic scale-out within us-east-1, while duplicating the stack in us-west-1 and using Route 53 failover routing with health checks gives the required active-passive regional DR behavior and automatic DNS failover when the primary becomes unhealthy.
C. Create a VPC in the us-west-1 Region. Use inter-Region VPC peering to connect both VPCs. Deploy an Application Load Balancer (ALB) that spans both VPCs. Deploy EC2 instances across multiple Availability Zones as part of an Auto Scaling group in each VPC served by the ALB. Create an Amazon Route 53 record that points to the ALB.
An ALB cannot span two VPCs; it is deployed within a single VPC.
D. Deploy an Application Load Balancer (ALB) spanning multiple Availability Zones (AZs) to the VPC in the us-east-1 Region. Deploy EC2 instances across multiple AZs as part of an Auto Scaling group served by the ALB. Deploy the same solution to the us-west-1 Region. Create separate Amazon Route 53 records in each Region that point to the ALB in the Region. Use Route 53 health checks to provide high availability across both Regions.
Separate Region-specific records do not create active-passive failover behavior.