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Difficulty: HardHigh Availability and Disaster Recovery Design

A commercial satellite imaging enterprise is designing a real-time satellite telemetry and command ingestion platform. The application tier consists of containerized microservices running on AWS Fargate behind an Application Load Balancer (ALB). The data tier uses an Amazon Aurora PostgreSQL database. The primary environment is hosted in the us-east-1 Region, and the company requires a disaster recovery (DR) environment in the us-west-2 Region.

The architecture must satisfy the following business and technical requirements:
- A Recovery Point Objective (RPO) of less than 1 minute.
- A Recovery Time Objective (RTO) of less than 15 minutes.
- Internal microservices must resolve service endpoints privately inside the VPCs of both Regions using the domain name satellite.internal.
- Outbound API commands sent from Fargate tasks to ground stations must remain highly available even if an entire Availability Zone experiences an outage.

Which of the following architectures meets these requirements with the lowest operational overhead?

  1. A
    Deploy Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. In both Regions, deploy Fargate tasks across two Availability Zones, routing outbound internet traffic from all private subnets through a single NAT Gateway located in the primary Availability Zone of each Region to optimize NAT running costs. Create a Route 53 Private Hosted Zone for satellite.internal and associate it with the VPCs in both us-east-1 and us-west-2. Set up Route 53 Failover routing with 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 both Regions, deploy Fargate tasks across at least two Availability Zones, configuring route tables to point outbound internet traffic to independent NAT Gateways in each Availability Zone. Create a Route 53 Private Hosted Zone for satellite.internal and associate it with the VPCs in both us-east-1 and us-west-2. Set up Route 53 Failover routing with health checks to manage external traffic redirection during a failover.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 both Regions, deploy Fargate tasks across at least two Availability Zones, configuring route tables to point outbound internet traffic to independent NAT Gateways in each Availability Zone. Create a Route 53 Private Hosted Zone for satellite.internal in us-east-1, but do not associate it with the VPC in us-west-2, relying instead on Route 53 Resolver endpoint rules to forward queries to us-east-1. Set up Route 53 Failover routing with health checks.
  4. D
    Configure AWS Backup to take hourly copy-replicated snapshots of the Amazon Aurora DB cluster in us-east-1 and copy them to us-west-2, restoring the database in the secondary Region during failover. In both Regions, deploy Fargate tasks across at least two Availability Zones, configuring route tables to point outbound internet traffic to independent NAT Gateways in each Availability Zone. Create a Route 53 Private Hosted Zone for satellite.internal and associate it with the VPCs in both us-east-1 and us-west-2. Set up Route 53 Failover routing with health checks.

Answer

The architecture that uses Amazon Aurora Global Database for sub-second cross-region replication, independent NAT Gateways in each Availability Zone of both Regions for high availability of outbound API calls, associates the Route 53 Private Hosted Zone with both regional VPCs for private name resolution, and uses Route 53 Failover routing for external traffic management.
The correct architecture uses Amazon Aurora Global Database to achieve low latency cross-region replication, ensuring that RPO and RTO goals are met. Outbound network traffic is protected from AZ failures by deploying redundant, local NAT Gateways within each zone. Private internal name resolution for satellite.internal is correctly established by associating the Route 53 Private Hosted Zone with the VPCs in both regions, and Route 53 Failover routing handles external traffic redirection smoothly.

Step-by-Step Solution

1
Evaluate the database replication strategy against RPO and RTO targets.
To meet an RPO under 1 minute and RTO under 15 minutes, cross-region replication must be continuous. Amazon Aurora Global Database provides sub-second replication latency, meeting the 1-minute RPO. Restoring from hourly backups fails both the RPO (1 hour) and RTO (restore time is typically >15 minutes).
Eliminates backup-and-restore options that fail RPO/RTO constraints.
2
Assess the high availability design of NAT Gateways for outbound container communication.
Configuring Fargate tasks across multiple AZs but routing all outbound traffic through a single NAT Gateway in one AZ exposes the system to complete outbound failure if that AZ goes down. Deploying independent NAT Gateways per AZ guarantees high availability.
Eliminates designs that introduce a single point of failure in outbound network pathways.
3
Confirm DNS configuration for internal resolution of custom hostnames across Regions.
Route 53 Private Hosted Zones must be explicitly associated with all VPCs that require local resolution of those private records. Without associating the hosted zone with the disaster recovery VPC, resources in the secondary region cannot resolve internal endpoints.
Secures functional name resolution in the secondary region during a failover event.

Key Concept

Disaster recovery design involving cross-region database replication, private DNS routing across multi-region VPCs, and Availability Zone level redundancy for egress networking.
Estimated Time:3m 0s
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Topics

High Availability and Disaster Recovery Design

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