Examkin

Question

Difficulty: HardHigh Availability and Disaster Recovery Design

A global telecommunications provider is deploying a critical SIM card provisioning platform on AWS. The application layer runs on Amazon EC2 instances in Auto Scaling groups behind Application Load Balancers (ALBs) across multiple Availability Zones in the primary region (us-east-1) and a recovery region (us-west-2). The application queries and updates customer provisioning profiles stored in an Amazon Aurora PostgreSQL Global Database, which has its primary cluster in us-east-1 and a secondary cluster in us-west-2. The application servers must periodically make outbound calls to external carrier networks via NAT Gateways. The architecture must achieve a Recovery Time Objective (RTO) of less than 10 minutes, a Recovery Point Objective (RPO) of less than 1 minute, mitigate against single Availability Zone failures within either region, and automate user traffic redirection to the secondary region if the primary region experiences a complete service disruption. Which two of the following configuration options should the solutions architect implement to meet these requirements? (Select TWO.)

  1. Configure Route 53 Failover routing records with health checks pointing to the regional Application Load Balancers. During a disaster event in the primary region, perform an unplanned managed failover of the Aurora Global Database to the recovery region to promote the secondary database cluster.Answer
  2. Deploy a NAT Gateway in each Availability Zone utilized by the application in both regions, and configure the route tables of the private subnets to direct outbound traffic to the NAT Gateway within their respective Availability Zone.Answer
  3. C
    Deploy a single NAT Gateway in a single public subnet in us-east-1 and another in us-west-2, and configure private subnet route tables across all Availability Zones in each region to route outbound traffic through these single entry points to minimize provisioning costs.
  4. D
    Associate the internal Route 53 Private Hosted Zone (PHZ) used for service discovery with the VPC in us-east-1, and rely on inter-region VPC peering to resolve local service hostnames from the us-west-2 VPC without local hosted zone association.
  5. E
    Configure Route 53 Geolocation routing to distribute user traffic evenly between both regions, and implement a pilot light disaster recovery strategy by replicating database snapshots once every hour to the recovery region.

Answer

Configure Route 53 Failover routing records with health checks pointing to the regional Application Load Balancers and perform an unplanned managed failover of the Aurora Global Database during a regional disaster; deploy a NAT Gateway in each Availability Zone utilized by the application in both regions, and configure private subnet route tables to direct outbound traffic to the local NAT Gateway in the same Availability Zone.
Implementing Route 53 Failover routing records ensures that traffic is automatically redirected to the secondary region if the primary region's ALB health checks fail. Performing an unplanned managed failover of the Aurora Global Database promotes the secondary cluster to primary while preserving the replication topology, satisfying the low RTO and RPO limits. Additionally, placing a NAT Gateway in each Availability Zone in both regions avoids a single point of failure for outbound carrier API connections, ensuring high availability within each region.

Step-by-Step Solution

1
Evaluate the disaster recovery requirements (RTO of less than 10 minutes, RPO of less than 1 minute) against database replication strategies.
Identify that Aurora Global Database storage-level replication is necessary to meet the sub-minute RPO, and a managed unplanned failover is required to meet the low RTO.
Traditional backup and restore or pilot light architectures using snapshots cannot guarantee data loss of less than a minute.
2
Analyze regional failover routing mechanisms for external client applications.
Determine that Route 53 Failover routing records combined with ALB health checks must be used to redirect public traffic to the recovery region during a disaster.
Active-passive failover routing automatically routes user traffic to the secondary region when the primary region is down, whereas geolocation routing distributes traffic without active health-based redirection.
3
Assess the outbound network path high availability requirements.
Determine that NAT Gateways must be deployed in every Availability Zone of the VPCs in both regions, with corresponding subnet route tables mapping to their local NAT Gateways.
A single NAT Gateway in one AZ creates a single point of failure that breaks outbound traffic for all other AZs if that specific AZ experiences an outage.
4
Verify internal DNS resolution requirements for the multi-region failover architecture.
Confirm the internal Route 53 Private Hosted Zone (PHZ) is associated with all VPCs across both regions.
VPC peering does not automatically share PHZ DNS resolution; explicit association is required to prevent cross-region internal DNS failures.

Key Concept

Designing high availability and disaster recovery architectures with multi-region DNS failover, database replication, and AZ-redundant networking.
Estimated Time:3m 0s
Rate this question

Topics

High Availability and Disaster Recovery Design

More questions from this topic