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Difficulty: MediumRoute 53 DNS Failover

A SysOps Administrator is setting up an active-passive disaster recovery solution using Amazon Route 53 for a public web application. The primary infrastructure runs in the us-west-2 Region behind an Application Load Balancer (ALB), and the backup infrastructure runs in the us-east-1 Region behind another ALB. The administrator wants to route all user traffic to us-west-2 under normal conditions, and automatically redirect traffic to us-east-1 if the primary application becomes unavailable. Which combination of actions must the administrator perform to configure this failover mechanism? (Select TWO.)

  1. Create an Alias record pointing to the primary Application Load Balancer in us-west-2, select the Failover routing policy, set the Failover Record Type to Primary, and set Evaluate Target Health to Yes.Answer
  2. Create an Alias record pointing to the backup Application Load Balancer in us-east-1, select the Failover routing policy, set the Failover Record Type to Secondary, and set Evaluate Target Health to Yes.Answer
  3. C
    Create a primary record using the Weighted routing policy with a weight of 100, and a secondary record using the Weighted routing policy with a weight of 0.
  4. D
    Enable detailed monitoring on the primary Application Load Balancer to configure a Route 53 health check that monitors a CloudWatch alarm for target response times.
  5. E
    Associate the primary Route 53 record with a custom health check that monitors the replication lag metric of an RDS Read Replica in the backup region.

Answer

The correct configuration requires creating a primary Failover Alias record pointing to the primary Application Load Balancer in us-west-2 with Evaluate Target Health set to Yes, and a secondary Failover Alias record pointing to the backup Application Load Balancer in us-east-1 with Evaluate Target Health set to Yes.
To configure an active-passive failover in Amazon Route 53 using Alias records pointing to Application Load Balancers, the administrator must create a primary record for the active endpoint and a secondary record for the standby endpoint. Setting the routing policy to Failover and configuring the Failover Record Type to Primary and Secondary respectively aligns with active-passive design. Enabling 'Evaluate Target Health' on both Alias records allows Route 53 to automatically evaluate the health of the load balancers based on the health of their registered targets, triggering the failover when the primary ALB's targets become unhealthy.

Step-by-Step Solution

1
Identify the routing policy and record type required for the primary endpoint.
A Failover routing policy with the Failover Record Type set to Primary pointing to the primary Application Load Balancer.
Active-passive disaster recovery setups in Route 53 require a Failover routing policy where the primary record represents the main active resource.
2
Determine how to monitor the health of the Application Load Balancer without extra cost or configuration.
Enable the 'Evaluate Target Health' setting on the Alias record.
When Evaluate Target Health is set to Yes, Route 53 inherits the health status of the Application Load Balancer from the backend EC2 targets registered with the ALB's target groups.
3
Configure the standby endpoint for failover.
A Failover routing policy with the Failover Record Type set to Secondary pointing to the backup ALB in the us-east-1 Region, with Evaluate Target Health set to Yes.
This ensures Route 53 will route DNS queries to the standby ALB when the primary ALB's health checks fail.

Key Concept

Active-passive Route 53 DNS failover configuration using Alias records and the Evaluate Target Health feature.
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Topics

Route 53 DNS Failover

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