Engineer Builds Testable AWS Multi-Region Disaster Recovery with Real Failover Under 15 Min

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A software engineer has built and open-sourced a multi-region 'pilot light' disaster recovery setup on AWS, using Terraform to replicate a notes API across two regions in Ireland and Paris. The architecture keeps the secondary region dormant — with zero running application instances — until a failure is detected, at which point Route 53 automatically flips DNS within roughly 30 seconds. PostgreSQL data is continuously replicated via a cross-region read replica, while S3 and Secrets Manager stay live in both regions simultaneously, minimizing manual intervention during failover. A single script handles the one step that cannot be automated — promoting the RDS read replica — targeting a full recovery time of 10 to 15 minutes. The project was designed to demonstrate that pilot light is the most cost-effective disaster recovery pattern achieving minute-scale RTO, and benchmarks each trade-off against AWS's Well-Architected Framework.

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ProgrammingDEV Community ·

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