Question #1855
A company hosts its web application using an Auto Scaling group of Amazon EC2 instances in a single AWS Region. To improve global availability and handle traffic spikes, the company deploys the application to a second Region. The solution must distribute traffic evenly across both Regions and only route users to Regions where the application is healthy.
Which configuration meets these requirements?
An Amazon Route 53 weighted routing policy with health checks for each Region
An Amazon Route 53 multivalue answer routing policy with health checks for each Region
A Network Load Balancer with target groups spanning instances in both Regions
An AWS Global Accelerator configured with endpoint groups in both Regions
Explanation
The solution requires distributing traffic evenly across two AWS Regions and routing only to healthy Regions. Option B (Route 53 multivalue answer routing policy with health checks) meets these requirements because:
1. Multivalue Answer Routing: Returns multiple healthy records (e.g., ALBs in each Region), allowing clients to connect to any available Region. This supports even distribution as clients can choose between Regions.
2. Health Checks: Ensures only Regions with healthy applications are included in DNS responses.
3. Handling Traffic Spikes: By returning multiple endpoints, clients can spread traffic across Regions, improving availability during spikes.
Why Other Options Fail:
- A (Weighted Routing): While it distributes traffic based on weights, it returns a single record per query, which may not handle client retries as effectively as multivalue.
- C (Network Load Balancer): NLBs are regional and cannot span multiple Regions.
- D (Global Accelerator): While it routes traffic globally, it requires explicit traffic dial configurations for even distribution, which is less direct than Route 53's multivalue approach.
Key Points:
- Use Route 53 multivalue answer routing for multi-Region HA with health checks.
- Multivalue returns multiple healthy endpoints, enabling client-side load balancing.
- Health checks ensure traffic is only sent to healthy Regions.
Answer
The correct answer is: B