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Difficulty: HardDeployment Strategy Design

An enterprise operates a high-performance web application deployed across two AWS Regions: us-east-1 and eu-west-1. Traffic is routed to the application endpoints via Amazon Route 53 using latency-based routing. The infrastructure team is designing a deployment strategy to release a major application update. The release requirements are:

1. The update must be rolled out to us-east-1 first, routing exactly 5% of the region's live traffic to the new version (the canary) to evaluate performance and error rates.
2. The remaining 95% of traffic in us-east-1 and 100% of traffic in eu-west-1 must continue to access the stable version.
3. If the canary deployment meets health metrics after 1 hour, traffic must be gradually shifted to 100% in us-east-1, followed by a similar rollout in eu-west-1.
4. If health metrics are violated, the canary traffic must be immediately redirected to the stable version without affecting latency-based routing for other users.

Which Route 53 configuration should a Solutions Architect recommend to implement this deployment strategy?

  1. A
    Create weighted records for the application domain to distribute traffic to the us-east-1 and eu-west-1 regions. Under each regional subdomain, create nested latency-based records pointing to the respective Application Load Balancers. Add a third top-level weighted record pointing directly to the new Application Load Balancer in us-east-1 with a weight of 5.
  2. B
    Change the routing policy of the primary domain from latency-based to geolocation-based routing. Route all traffic from North America to a weighted record set containing the stable and new Application Load Balancer endpoints in us-east-1 with weights of 95 and 5, respectively. Route European traffic to the stable Application Load Balancer in eu-west-1.
  3. Create latency-based Alias records for the application domain. Point the latency record for the us-east-1 region to a nested weighted record set for a regional subdomain. Configure this subdomain with two records in the us-east-1 region: one pointing to the stable Application Load Balancer with a weight of 95, and one pointing to the new Application Load Balancer with a weight of 5.Answer
  4. D
    Create a single latency-based record set for the application domain. Add a latency record for eu-west-1 pointing to the stable Application Load Balancer, a latency record for us-east-1 with a weight of 95 pointing to the stable Application Load Balancer, and a latency record for us-east-1 with a weight of 5 pointing to the new Application Load Balancer.

Answer

The correct strategy is to nest a weighted record set under a latency-based alias record. This configuration first routes users to the nearest region using latency routing, and then distributes the US regional traffic between the stable and new Application Load Balancer endpoints using a 95/5 weight distribution.
The correct architecture uses nested Route 53 records to combine latency-based routing and weighted routing. By defining latency-based alias records at the top level pointing to regional subdomains, users are first routed to the closest region. For the US region, the traffic is directed to a nested weighted record set, which then distributes 95% of the traffic to the stable Application Load Balancer and 5% to the new canary Application Load Balancer. This preserves latency-based routing for all users while enabling a controlled canary release in a single region.

Step-by-Step Solution

1
Define the top-level DNS routing configuration.
Create latency-based Alias records for the primary application domain.
This ensures that DNS requests are routed to the nearest regional endpoint based on user latency.
2
Configure regional traffic splitting for the canary deployment.
Point the us-east-1 latency-based record to a nested subdomain containing a weighted record set with weights of 95 and 5.
This splits traffic within the us-east-1 region, sending 5% of the users to the new version (canary) and 95% to the stable version.
3
Configure the stable region routing.
Point the eu-west-1 latency-based record directly to the stable ALB in eu-west-1.
This ensures that 100% of the traffic in eu-west-1 continues to use the stable version without interruption.

Key Concept

Combining Amazon Route 53 latency-based routing with weighted routing using nested records to perform a regional canary deployment.
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Topics

Deployment Strategy Design

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