Question #996
A global e-commerce platform hosts its application on Amazon EC2 instances behind Application Load Balancers (ALBs) in two AWS Regions. The platform requires users to be directed to the nearest Region for low latency. If the nearest Region becomes unavailable, traffic should automatically redirect to the other Region. What should a solutions architect do to meet these requirements?
Create an Amazon CloudFront distribution with an origin group containing both ALBs. Configure one ALB as the primary origin and enable origin failover.
Create Amazon Route 53 health checks for each ALB. Configure a failover routing policy with active-passive ALB endpoints, setting the Evaluate Target Health parameter to Yes.
Deploy two Amazon CloudFront distributions, each with one ALB as its origin. Use a Route 53 failover routing record pointing to the CloudFront distributions, with Evaluate Target Health enabled.
Configure Amazon Route 53 latency alias records pointing to both ALBs. Enable health checks for each ALB and set the Evaluate Target Health parameter to Yes.
Explanation
Option D is correct because Amazon Route 53's latency-based routing policy directs traffic to the AWS Region that provides the lowest latency. By configuring latency alias records pointing to both ALBs and enabling health checks with the 'Evaluate Target Health' parameter set to Yes, Route 53 will automatically route traffic to the nearest healthy Region. If the nearest Region becomes unhealthy, traffic fails over to the next lowest-latency Region.
Other options are incorrect because:
- A: CloudFront origin groups handle failover but do not inherently route based on user latency to Regions.
- B: Failover routing policies are active-passive and do not prioritize low-latency routing.
- C: Using two CloudFront distributions with Route 53 failover adds complexity and does not leverage latency-based routing.
Key Points:
1. Use Route 53 latency routing for directing users to the nearest Region.
2. Enable health checks to detect regional failures and trigger automatic failover.
3. 'Evaluate Target Health=Yes' ensures Route 53 considers ALB health status.
Answer
The correct answer is: D