This segment focuses on implementing a failover routing policy using AWS Route 53, which involves redirecting traffic from a primary to a secondary resource in case of failure. Here's a concise summary and key points:

Failover Routing Policy in AWS Route 53

• Objective: Ensure high availability by automatically redirecting DNS queries from an unhealthy primary resource to a healthy secondary resource.
• Components:
  • Route 53: Manages DNS records and health checks.
  • EC2 Instances: Serve as primary and secondary (disaster recovery) resources.
  • Health Checks: Monitor the health of the resources.

Implementation Steps

1. Health Check Association:
   • Mandatory for the primary resource.
   • Optional for the secondary resource.
   • Determines the health status of the resources.
2. DNS Request Handling:
   • Route 53 responds with the primary record if the primary resource is healthy.
   • Route 53 automatically fails over to the secondary record if the primary resource is unhealthy.

Hands-on Example

• Domain: failover.stephanetheteacher.com
• Record Type: A (Address Record)
• TTL (Time to Live): Set to a low value (60 seconds) to quickly propagate changes.
• Routing Policy: Failover, with options for primary or secondary records.
• Health Check Association:
  • Primary record associated with a health check named EU-central-1.
  • Secondary record can optionally be associated with its health check.
• Implementation:
  • Create primary and secondary records in Route 53.
  • Associate the primary record with a health check.
  • Optionally associate the secondary record with a health check.
  • Test failover by simulating a failure (e.g., editing security group rules to block traffic).

Testing Failover

• Triggering a Failure: Edit inbound rules of the security group to block traffic to the primary instance, causing the health check to fail.
• Observation: After the health check fails, Route 53 automatically redirects traffic to the secondary instance.
• Recovery: Edit the security group to allow traffic again, which restores the health check status and fails back to the primary instance.

Conclusion