Examkin

Question

Difficulty: MediumRoute 53 Routing Policies and DNS Failover Strategies

A company runs a global mobile application with backend APIs hosted on Amazon EC2 instances behind Application Load Balancers (ALBs) in both the us-west-2 and eu-central-1 regions. Under normal conditions, users should be directed to the closest region to minimize latency. If the application in one region becomes unavailable, traffic must be automatically routed to the other region. The database backend consists of an Amazon Aurora Global Database with the primary cluster in us-west-2 and a read-only secondary cluster in eu-central-1. Which configuration should the solutions architect choose to meet these requirements?

  1. Create Route 53 Latency-based alias records pointing to the ALBs in both regions, and enable Evaluate Target Health on both records.Answer
  2. B
    Create Route 53 Failover records with the us-west-2 ALB as primary and the eu-central-1 ALB as secondary, configuring a latency routing policy on the primary record.
  3. C
    Create Route 53 Latency-based CNAME records pointing to the ALBs, set the Time to Live (TTL) to 0 seconds, and enable Evaluate Target Health on both records.
  4. D
    Create Route 53 Latency-based alias records pointing to the ALBs in both regions, and rely on Route 53 to automatically promote the Amazon Aurora read replica in eu-central-1 to primary if the us-west-2 region fails.

Answer

Create Route 53 Latency-based alias records pointing to the ALBs in both regions, and enable Evaluate Target Health on both records.
The correct configuration uses Route 53 Latency-based alias records pointing to the Application Load Balancers in both regions with Evaluate Target Health enabled. This ensures that users are directed to the region with the lowest latency under normal conditions. If one of the regions becomes unavailable, Route 53 detects the unhealthy status of the ALB and automatically routes subsequent DNS requests to the healthy region.

Step-by-Step Solution

1
Analyze the business requirements for latency and availability.
Under normal operations, traffic must route to the region with lowest latency (us-west-2 or eu-central-1), which requires an active-active configuration using Latency-based routing.
Latency-based routing ensures users are automatically directed to the AWS region that provides the lowest network latency.
2
Configure health checks for failover capability.
Evaluate Target Health must be enabled on the Route 53 Alias records pointing to the Application Load Balancers.
This allows Route 53 to inherit the health status of the ALBs from the load balancer target groups, preventing traffic from being sent to an unhealthy region.
3
Select the correct Route 53 record type.
Use Alias records instead of standard CNAME records.
Alias records are required to use the Evaluate Target Health feature and allow routing at the zone apex.

Key Concept

Combining Route 53 Latency Routing with Evaluate Target Health on Alias records allows active-active routing with automatic failover.
Rate this question

Topics

Route 53 Routing Policies and DNS Failover Strategies

More questions from this topic