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Difficulty: MediumRoute 53 Routing Policies and DNS Failover Strategies

A logistics platform is designing an active-passive disaster recovery strategy for its tracking portal under the apex domain logistics-track.com. The primary application is hosted behind an Application Load Balancer (ALB) in the us-east-1 Region, while the secondary disaster recovery site is a static maintenance page hosted on Amazon S3 in the us-west-2 Region. The platform requires that users be directed automatically to the maintenance page if the primary application in us-east-1 becomes unavailable. Which Route 53 configuration should a solutions architect implement to meet these requirements with the least operational overhead?

  1. Create a primary Failover Alias record for logistics-track.com pointing to the ALB with Evaluate Target Health set to Yes. Create a secondary Failover Alias record pointing to the Amazon S3 bucket.Answer
  2. B
    Create a primary Latency Alias record for logistics-track.com pointing to the ALB with Evaluate Target Health set to Yes. Create a secondary Latency Alias record pointing to the S3 bucket to automatically route based on regional responsiveness.
  3. C
    Create a primary Failover CNAME record for logistics-track.com pointing to the ALB DNS name. Create a secondary Failover CNAME record pointing to the Amazon S3 static website endpoint.
  4. D
    Create a primary Failover Alias record for logistics-track.com pointing to the ALB. Create a secondary Failover Alias record pointing to an Amazon RDS read replica DNS endpoint in us-west-2 to serve the maintenance page data directly.

Answer

Create a primary Failover Alias record for logistics-track.com pointing to the ALB with Evaluate Target Health set to Yes, and a secondary Failover Alias record pointing to the S3 bucket.
The correct configuration uses Route 53 Alias records because CNAME records are invalid at the zone apex (logistics-track.com). It leverages the Failover routing policy to route traffic to the primary ALB when healthy and fall back to the secondary S3 bucket when unhealthy. By setting Evaluate Target Health to Yes, Route 53 automatically monitors the health of the backend targets registered with the ALB, removing the operational overhead of setting up separate Route 53 health checks.

Step-by-Step Solution

1
Determine the record type for the zone apex domain.
An Alias record must be used because standard DNS CNAME records cannot be created at the zone apex (logistics-track.com).
Alias records allow Route 53 to map the zone apex directly to selected AWS resources like ALBs and S3 buckets.
2
Select the appropriate routing policy for the active-passive disaster recovery requirement.
Failover routing policy is selected.
Failover routing is specifically designed for active-passive disaster recovery configurations where traffic is sent to a primary resource when healthy, and to a secondary resource when the primary is unhealthy.
3
Configure health checks for the primary destination.
Set Evaluate Target Health to Yes on the primary record.
Setting Evaluate Target Health to Yes allows Route 53 to use the health checks defined on the ALB's target groups, eliminating the need to create and manage custom Route 53 health checks manually.

Key Concept

Route 53 DNS Failover for Zone Apex using Alias Records
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Topics

Route 53 Routing Policies and DNS Failover Strategies

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