Question #971
A solutions architect has deployed a web application that serves users across two AWS Regions under a custom domain. The application uses Amazon Route 53 latency-based routing. The solutions architect has associated weighted record sets with a pair of web servers in separate Availability Zones for each Region. During a disaster recovery test, when all web servers in one Region are terminated, Route 53 does not automatically redirect users to the remaining Region. Which of the following are possible root causes of this issue? (Choose two.)
The weight for the terminated Region's weighted records is set lower than the weight for the active Region's records.
The health checks for the active Region's web servers are configured with an incorrect path.
Latency-based routing policies cannot be combined with weighted routing policies for the same domain.
The 'Evaluate Target Health' option is disabled for the latency alias records pointing to the terminated Region's weighted records.
The weighted records associated with the terminated Region's web servers do not have health checks configured.
Explanation
The correct answers are D and E.
Why D is correct: If 'Evaluate Target Health' is disabled for the latency alias records pointing to the terminated region's weighted records, Route 53 cannot check the health of the targets. Even if the servers are terminated, the latency-based routing policy continues to route traffic to the unhealthy region.
Why E is correct: If the weighted records for the terminated region lack health checks, Route 53 assumes they are healthy. Traffic continues to be routed to the terminated region despite server unavailability.
Why others are incorrect:
- A: Lower weight for the terminated region would not prevent redirection if health checks are functioning.
- B: Incorrect health checks for the active region would mark its servers as unhealthy, but the question focuses on the terminated region's servers.
- C: Latency-based routing can be combined with weighted policies via alias records.
Key Points:
1. Route 53 relies on health checks to detect failures.
2. 'Evaluate Target Health' must be enabled for alias records to respect target health.
3. Weighted records without health checks are always considered healthy.
Answer
The correct answer is: DE