A telecommunications company is designing a new real-time network fault monitoring system … — AWS Certified Solutions Architect - Professional

A telecommunications company is designing a new real-time network fault monitoring system on AWS. The application will be deployed across two AWS Regions: `us-west-2` (Primary) and `us-east-1` (Secondary). The architecture requires an active-passive disaster recovery strategy with a Recovery Time Objective (RTO) of $\leq 5$ minutes and a Recovery Point Objective (RPO) of $\leq 1$ minute. The application runs on Amazon EC2 instances in private subnets, which must regularly connect to external diagnostic probes on the internet. For internal service communication, microservices rely on a shared Route 53 Private Hosted Zone named `corp.internal`. Which of the following architectures meets these requirements while minimizing regional failover time and ensuring high availability within each Region?

A
Deploy an Amazon Aurora Global Database with the primary cluster in us-west-2 and a secondary cluster in us-east-1. In each VPC, deploy a single NAT Gateway in one Availability Zone to optimize costs, and route all outbound private subnet traffic through it. Associate the Route 53 Private Hosted Zone corp.internal with the VPCs in both Regions. Use Route 53 Application Recovery Controller (ARC) routing controls to manage regional traffic failover.
Deploy an Amazon Aurora Global Database with the primary cluster in us-west-2 and a secondary cluster in us-east-1. In both VPCs, deploy a NAT Gateway in each Availability Zone. Associate the Route 53 Private Hosted Zone corp.internal with the VPCs in both Regions. Use Route 53 Application Recovery Controller (ARC) routing controls to manage traffic redirection between Regions.Answer
C
Deploy Amazon RDS PostgreSQL Multi-AZ in us-west-2 with a cross-region read replica in us-east-1. In both VPCs, deploy a NAT Gateway in each Availability Zone. Associate the Route 53 Private Hosted Zone corp.internal with both VPCs. Use Route 53 Failover routing policies to route traffic. During a regional outage, manually promote the read replica to a standalone database and update Route 53.
D
Deploy an Amazon Aurora Global Database with the primary cluster in us-west-2 and a secondary cluster in us-east-1. In both VPCs, deploy a NAT Gateway in each Availability Zone. Create the Route 53 Private Hosted Zone corp.internal and associate it only with the us-west-2 VPC. Use Route 53 Application Recovery Controller (ARC) routing controls to manage regional traffic failover.

Answer

The correct architecture uses Amazon Aurora Global Database for database replication, deploys a NAT Gateway in each Availability Zone of both VPCs, associates the Route 53 Private Hosted Zone corp.internal with both VPCs, and implements Route 53 Application Recovery Controller (ARC) routing controls for multi-region failover.

The correct architecture leverages Amazon Aurora Global Database, which replicates data with sub-second latency to meet the

1

-minute RPO and can be promoted via managed failover in under a minute to satisfy the

5

-minute RTO. A NAT Gateway in each Availability Zone of both VPCs guarantees redundant internet egress, and associating the Route 53 Private Hosted Zone corp.internal with both VPCs ensures that internal services can resolve names before and after a regional failover. Route 53 ARC controls allow for rapid, deterministic routing changes.

Step-by-Step Solution

Evaluate the database replication strategy against RTO and RPO constraints.

Amazon Aurora Global Database provides typical replication lag of less than

1

second (satisfying the

1

-minute RPO) and supports managed failover that promotes the secondary region in less than

1

minute (satisfying the

5

-minute RTO). Amazon RDS with manual read replica promotion cannot reliably meet the

5

-minute RTO.

Choosing the correct disaster recovery pattern is critical to meet the strict RTO and RPO targets.

Examine internal DNS configuration across VPCs.

A Route 53 Private Hosted Zone (PHZ) must be explicitly associated with the VPCs in both Regions to allow resources in either Region to resolve the internal domain names.

Failing to associate the PHZ with the secondary VPC results in name resolution failures when traffic shifts to the secondary region.

Ensure outbound connectivity redundancy within each Region.

Deploying a NAT Gateway in each Availability Zone of both VPCs prevents a single AZ outage from interrupting outbound internet communication to the diagnostic probes.

Using a single NAT Gateway per Region creates a single point of failure, violating local high-availability requirements.

Key Concept

High Availability and Disaster Recovery Design for Multi-Region Architectures

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