DOP-C02 Question 134
Single answerYour company runs a distributed application across multiple AWS Regions using Amazon EC2 instances behind an Elastic Load Balancer (ELB). To improve resiliency, you have implemented Route 53 with a multi-Region failover routing policy. During a failover scenario, you notice that traffic is not being routed to the healthy Region as expected. What could be the cause of this issue?
- A
The health checks associated with Route 53 are not configured for the ELB endpoints in each Region.
- B
The Elastic Load Balancer's target group health checks are failing in the primary Region.
- C
Route 53 failover routing does not support multi-Region setups.
- D
The DNS TTL (Time to Live) for your Route 53 record set is set too low.
Show answer and explanation
Correct answer: A
Explanation
For Route 53 failover routing to work correctly, health checks must be configured for each Region's ELB endpoint. These health checks determine whether the primary Region is healthy and whether traffic should be routed to the secondary Region in case of a failure. If the health checks are not properly set up, Route 53 cannot detect the failure, leading to incorrect routing of traffic.
- A. Correct.
This is correct. Route 53 failover routing relies on health checks to determine whether to route traffic to the primary or secondary Regions. If the health checks are not properly configured for the ELB endpoints, Route 53 will not detect the failure and will continue routing traffic to the primary Region.
- B. Incorrect.
This is incorrect. While failing health checks in the primary Region's ELB might be a symptom of the issue, Route 53 routing is based on its own health checks and not the ELB target group health checks.
- C. Incorrect.
This is incorrect. Route 53 failover routing does support multi-Region setups, and the issue is more likely due to misconfiguration.
- D. Incorrect.
This is incorrect. A low DNS TTL does not cause traffic misrouting. It only controls how quickly DNS changes propagate to clients.