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Difficulty: MediumRoute 53 Routing Policies and DNS Failover Strategies

An online banking platform uses an Application Load Balancer (ALB) in the eu-west-1 Region to route portal traffic to backend EC2 instances. To meet disaster recovery compliance, the organization has deployed a warm standby replica of their application stack in the ap-southeast-2 Region, which includes a standby ALB and a cross-region Amazon RDS Read Replica. The organization wants to configure Amazon Route 53 to support automated active-passive routing for their zone apex domain (bank.com). If the primary region's ALB becomes unhealthy, traffic must fail over to the standby region, where the database replica will be promoted manually. Which Route 53 routing configuration should a solutions architect recommend to meet these requirements?

  1. Create a primary Failover Alias record for bank.com pointing to the eu-west-1 ALB, and a secondary Failover Alias record pointing to the ap-southeast-2 ALB. Set Evaluate Target Health to Yes on both records.Answer
  2. B
    Create a primary CNAME record at the zone apex for bank.com pointing to the eu-west-1 ALB, and a secondary CNAME record pointing to the ap-southeast-2 ALB, configuring both with a Failover routing policy.
  3. C
    Create two Latency Alias records for bank.com pointing to the respective ALBs, and disable Route 53 health checks to allow Latency routing to automatically route all users to the secondary region if the primary region experiences an outage.
  4. D
    Create a primary Failover Alias record pointing to the eu-west-1 ALB, and a secondary Failover Alias record pointing directly to the Amazon RDS Read Replica endpoint to automate application and database failover simultaneously.

Answer

Create a primary Failover Alias record for bank.com pointing to the eu-west-1 ALB, and a secondary Failover Alias record pointing to the ap-southeast-2 ALB. Set Evaluate Target Health to Yes on both records.
The correct configuration uses Route 53 Failover routing with Alias records pointing to the Application Load Balancers. Alias records are required because the destination is the zone apex domain (bank.com), which cannot have CNAME records. Setting 'Evaluate Target Health' to Yes allows Route 53 to inherit the health status of the ALB targets directly, enabling automated DNS failover without requiring separate custom health checks.

Step-by-Step Solution

1
Select the correct record type and routing policy for active-passive failover at the zone apex.
Identify that a Failover routing policy is required for active-passive routing, and Alias records must be used instead of CNAME records because the target is the zone apex (bank.com).
DNS RFCs do not allow CNAME records at the zone apex, but Route 53 Alias records can map the zone apex directly to AWS resources like ALBs.
2
Configure health checking to monitor the primary and secondary endpoints.
Set Evaluate Target Health to Yes on both the primary and secondary Alias records.
Setting Evaluate Target Health to Yes tells Route 53 to evaluate the health of the ALB using its target group health checks, eliminating the need to configure custom Route 53 health checks.
3
Verify database promotion requirements.
Ensure that the RDS Read Replica promotion remains a separate operational step, as Route 53 is a DNS service and cannot promote databases.
Route 53 only handles DNS routing; database failover/promotion must be handled at the database or application layer.

Key Concept

Route 53 Failover Routing with Alias Records
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Topics

Route 53 Routing Policies and DNS Failover Strategies

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