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Difficulty: MediumRoute 53 Routing Policies and DNS Failover Strategies

A retail company hosts a customer-facing e-commerce application on Amazon EC2 instances behind an Application Load Balancer (ALB) in the us-east-1 Region. For disaster recovery (DR), the company has deployed a scaled-down standby environment in the us-west-2 Region with a standby ALB. The company wants to implement an active-passive disaster recovery strategy where Route 53 automatically redirects all incoming traffic to the standby ALB in us-west-2 only if the application in us-east-1 is unhealthy. The target Recovery Time Objective (RTO) is less than 2 minutes. Which TWO configurations must the solutions architect implement to meet these requirements? (Select TWO.)

  1. Create a Route 53 Failover Alias record for the primary ALB, setting the routing policy to Primary and Evaluate Target Health to Yes.Answer
  2. Create a Route 53 Failover Alias record for the standby ALB, setting the routing policy to Secondary and Evaluate Target Health to Yes.Answer
  3. C
    Create Route 53 Latency routing records for both regional ALBs to automatically route user traffic based on the lowest network latency.
  4. D
    Configure the standby environment as a pilot light deployment with all EC2 instances stopped, and use Route 53 health checks to start the instances automatically during failover.
  5. E
    Configure a Route 53 health check to monitor the Amazon RDS read replica in the standby region and automatically promote it to primary when the primary database goes offline.

Answer

Create a Route 53 Failover Alias record for the primary ALB, setting the routing policy to Primary and Evaluate Target Health to Yes; and create a Route 53 Failover Alias record for the standby ALB, setting the routing policy to Secondary and Evaluate Target Health to Yes.
To configure active-passive failover with Amazon Route 53, a solutions architect should create two failover records: one primary and one secondary. By using Alias records pointing to the Application Load Balancers (ALBs) and enabling the 'Evaluate Target Health' option, Route 53 automatically monitors the health of the targets in the target groups. If the targets behind the primary ALB fail their health checks, Route 53 will automatically stop routing traffic to the primary ALB and begin routing it to the secondary standby ALB, keeping failover time minimal and meeting the recovery time objective.

Step-by-Step Solution

1
Analyze the disaster recovery requirement.
The requirements demand an active-passive cross-region failover strategy with an RTO of less than 2 minutes.
This establishes that we need a fast DNS-based failover mechanism using Route 53 and a warm standby environment that is ready to accept traffic immediately.
2
Select the appropriate routing policy.
Amazon Route 53 Failover routing policy is designed specifically for active-passive configurations.
Other routing policies like Latency routing are intended for active-active configurations rather than strict active-passive failover.
3
Configure health checks and target evaluation.
Configure Primary and Secondary Failover Alias records pointing to the respective ALBs with 'Evaluate Target Health' set to Yes.
Setting 'Evaluate Target Health' to Yes on the Alias records allows Route 53 to check the health of the backend EC2 targets behind the ALBs directly, enabling rapid failover within the RTO budget without requiring manually created external health checks.

Key Concept

Amazon Route 53 Active-Passive Failover Routing
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Topics

Route 53 Routing Policies and DNS Failover Strategies

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