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Difficulty: EasyEnhancing Reliability and Disaster Recovery

A company has configured an active-passive disaster recovery strategy for its web application across two AWS Regions. They use Amazon Route 53 with failover routing policies to direct traffic. During a disaster recovery simulation, the primary region's application server is shut down, but Route 53 continues to resolve DNS queries to the primary region's load balancer. Which of the following is the most likely cause of this behavior?

  1. A
    The Route 53 Private Hosted Zone is not associated with the Virtual Private Cloud (VPC) in the secondary region.
  2. B
    The primary region's Application Load Balancer is pointing to a single non-redundant NAT Gateway.
  3. The failover routing record for the primary region is not associated with a Route 53 health check.Answer
  4. D
    The disaster recovery strategy is configured as pilot light instead of active-active replication.

Answer

The failover routing record for the primary region is not associated with a Route 53 health check.
The correct answer is that the failover routing record for the primary region is not associated with a Route 53 health check. Route 53 requires a health check to be associated with a record to determine when to fail over. Without a health check, Route 53 considers the endpoint healthy by default and continues to route traffic to the primary region.

Step-by-Step Solution

1
Analyze how Amazon Route 53 determines endpoint health for failover routing.
Route 53 relies on health checks associated with the resource record sets to evaluate whether an endpoint is healthy or unhealthy.
If no health check is associated with the primary record, Route 53 assumes the primary endpoint is always healthy.
2
Identify the cause of the failover failure during the simulation.
Since the server was shut down but DNS traffic was not redirected, Route 53 was unable to detect the outage.
This indicates a missing association between the Route 53 failover record and a health check monitoring the primary endpoint.

Key Concept

Amazon Route 53 DNS Failover and Health Checks
Estimated Time:1m 0s
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Topics

Enhancing Reliability and Disaster Recovery