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Difficulty: MediumAmazon Route 53 DNS Configuration and Routing Policies

A company hosts its web application at the zone apex (`example.com`). The application is deployed behind Application Load Balancers (ALBs) in two AWS Regions: `us-east-1` and `eu-west-1`. A SysOps Administrator must configure Amazon Route 53 to route user traffic to the region that provides the lowest network latency. The solution must support automated failover to the other region if the local ALB becomes unhealthy. Which two Route 53 configurations should the SysOps Administrator implement to meet these requirements?

  1. Create Latency routing Alias A records for `example.com` pointing to the ALB DNS name in each AWS Region.Answer
  2. Configure the Evaluate Target Health setting to Yes on the created Alias records.Answer
  3. C
    Create Latency routing CNAME records for `example.com` pointing to the ALB DNS name in each AWS Region.
  4. D
    Create Failover routing Alias A records for `example.com` with the `us-east-1` ALB as primary and the `eu-west-1` ALB as secondary.
  5. E
    Create Geolocation routing Alias A records for `example.com` pointing to the ALB DNS name in each AWS Region.

Answer

Create Latency routing Alias A records for the zone apex pointing to the ALB DNS names, and configure the Evaluate Target Health setting to Yes on these Alias records.
To route traffic based on network latency for a zone apex domain, the administrator must use Latency routing Alias A records. Unlike CNAME records, Alias records can be used at the zone apex. Additionally, to support automatic failover, the Evaluate Target Health property must be set to Yes on these Alias records, which leverages ALB health checks to determine resource availability.

Step-by-Step Solution

1
Identify the record type required for the zone apex
Determine that a CNAME record cannot be used at the zone apex (`example.com`), which requires the use of Route 53 Alias A records pointing to the ALBs.
DNS RFC standards prohibit CNAME records at the zone apex.
2
Select the appropriate routing policy for lowest network latency
Choose Latency routing to route users to the region with the lowest round-trip network time.
Latency routing directly measures and optimizes for network latency between the client and AWS Regions.
3
Configure the health checking and failover mechanism
Enable 'Evaluate Target Health' on the Alias records.
Enabling 'Evaluate Target Health' allows Route 53 to check the health of the ALB using its target groups, automatically failing over to the other region if the primary region's ALB becomes unhealthy.

Key Concept

Route 53 Latency routing combined with Alias records and Evaluate Target Health at the zone apex.
Estimated Time:1m 30s
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Topics

Amazon Route 53 DNS Configuration and Routing Policies

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