Examkin

Question

Difficulty: HardHigh Availability and Disaster Recovery Design

An international maritime shipping corporation is designing a high-availability and disaster recovery solution for its core cargo routing system on AWS. The system is deployed in a VPC in us-east-1 (primary) and must failover to a VPC in us-west-2 (secondary). The business requires a recovery time objective (RTO) of 15 minutes and a recovery point objective (RPO) of 2 minutes.

The application tier consists of Amazon EC2 instances in an Auto Scaling group in private subnets, which make outbound API calls to external customs agencies via NAT Gateways. For internal microservices communication, the corporation uses a Route 53 Private Hosted Zone (PHZ) named internal.cargo.platform to resolve service endpoints. The database tier uses Amazon Aurora PostgreSQL.

Which architecture will meet these requirements with the lowest RTO and RPO while maintaining database and network redundancy in the secondary region?

  1. A
    Deploy Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. In us-west-2, deploy the application tier using an Auto Scaling group running at a minimal scale, and provision redundant NAT Gateways across multiple Availability Zones. Associate the Route 53 Private Hosted Zone internal.cargo.platform only with the VPC in us-east-1. Configure Route 53 public Failover routing records pointing to the Application Load Balancers in both regions, associated with Application Load Balancer health checks.
  2. Deploy Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. In us-west-2, deploy the application tier using an Auto Scaling group running at a minimal scale, and provision redundant NAT Gateways across multiple Availability Zones. Associate the Route 53 Private Hosted Zone internal.cargo.platform with the VPCs in both regions. Configure Route 53 public Failover routing records pointing to the Application Load Balancers in both regions, associated with Application Load Balancer health checks.Answer
  3. C
    Deploy Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. In us-west-2, deploy the application tier using an Auto Scaling group running at a minimal scale, and provision a single NAT Gateway in one Availability Zone to optimize standby costs. Associate the Route 53 Private Hosted Zone internal.cargo.platform with the VPCs in both regions. Configure Route 53 public Failover routing records pointing to the Application Load Balancers in both regions, associated with Application Load Balancer health checks.
  4. D
    Configure AWS Backup to take hourly snapshots of the Aurora PostgreSQL database in us-east-1 and copy them to us-west-2. In us-west-2, deploy the application tier using an Auto Scaling group set to a minimum capacity of zero, and provision redundant NAT Gateways across multiple Availability Zones. Associate the Route 53 Private Hosted Zone internal.cargo.platform with the VPCs in both regions. Configure Route 53 public Failover routing records pointing to the Application Load Balancers in both regions, associated with Application Load Balancer health checks.

Answer

The correct design utilizes Amazon Aurora Global Database for sub-second cross-region replication, maintains redundant NAT Gateways in the secondary region to avoid outbound single points of failure, associates the Private Hosted Zone with both regional VPCs to ensure internal name resolution works upon failover, and implements Route 53 Failover routing for automated public ingress redirection.
The correct architecture uses Amazon Aurora Global Database to guarantee sub-second data replication across regions, satisfying the 2-minute RPO. It deploys the application tier in a warm standby configuration in us-west-2 and configures Route 53 Failover routing records to dynamically redirect public traffic when an outage is detected in us-east-1, meeting the 15-minute RTO. Redundancy is preserved by deploying NAT Gateways in multiple Availability Zones in the secondary VPC, and internal microservice names are kept resolvable by associating the Route 53 Private Hosted Zone with both regional VPCs.

Step-by-Step Solution

1
Select a cross-region database replication mechanism that meets the RPO and RTO bounds.
Choose Amazon Aurora Global Database, which offers sub-second cross-region replication latency and can be promoted to a primary cluster in under a minute.
This guarantees compliance with the 2-minute RPO and 15-minute RTO, whereas snapshot copy and restore mechanisms cannot.
2
Ensure internal DNS names remain resolvable after failover.
Associate the Route 53 Private Hosted Zone (PHZ) internal.cargo.platform with the VPCs in both us-east-1 and us-west-2.
Route 53 PHZ domain names are only resolvable within VPCs that have been explicitly associated with the hosted zone.
3
Design highly available outbound internet access in the secondary VPC.
Deploy NAT Gateways in multiple Availability Zones in us-west-2.
Using a single NAT Gateway introduces a single point of failure, risking complete loss of outbound carrier API connectivity in the event of an AZ outage.
4
Configure DNS failover for external traffic incoming to the Application Load Balancers.
Use Route 53 Failover routing policies targeting the Application Load Balancers in both regions and tie them to health checks.
This automatically redirects ingress public traffic to the secondary region if the primary region's ALB or application endpoints become degraded.

Key Concept

Designing multi-region active-passive architectures using Aurora Global Database, Route 53 Failover routing, redundant NAT Gateways, and multi-VPC Private Hosted Zone association.
Rate this question

Topics

High Availability and Disaster Recovery Design

More questions from this topic