Multi-Region High Availability & Disaster Recovery (HADR) for Django

Designed and architected a robust, multi-region AWS infrastructure to host a mission-critical Django application. The solution implements a Warm Standby disaster recovery strategy, ensuring a Recovery Point Objective (RPO) of seconds and a Recovery Time Objective (RTO) of minutes, while optimizing for cost-efficiency.

AWS Multi-Region Architecture Diagram
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Technical Architecture Breakdown

1. Global Traffic Management & DNS

  • Service: Amazon Route 53
  • Implementation: Configured Failover Routing policies with integrated Health Checks.
  • Logic: Traffic is directed to the Primary Region (us-west-2) by default. If the primary health check fails, Route 53 automatically updates DNS records to point to the Secondary Region (us-east-1).

2. Scalable Compute Layer (Django App)

  • Services: EC2, Application Load Balancer (ALB), Auto Scaling Group (ASG)
  • Availability: Deployed across three Availability Zones (Multi-AZ) in each region to ensure fault tolerance.
  • Warm Standby Logic:
    • Region 1 (Primary): Runs at full production capacity to handle active user load.
    • Region 2 (Secondary): Maintained at "minimum scale" (1 small instance) to keep the environment warm. This reduces idle costs by ~80% compared to a Hot Standby, while allowing the ASG to scale up to production levels immediately upon failover.

3. Data Persistence & Replication

  • Service: Amazon RDS (PostgreSQL/MySQL)
  • Strategy:
    • Primary Region: Multi-AZ deployment for synchronous local failover.
    • Cross-Region: Established an Asynchronous Read Replica in Region 2.
  • Failover Protocol: In a disaster scenario, the Read Replica is manually promoted to a standalone Primary instance to accept write traffic, ensuring minimal data loss.

4. Networking & Security

  • VPC Design: Isolated VPCs in both regions with non-overlapping CIDR blocks to allow for future VPC Peering or Shared Services expansion.
  • Security: Implemented IAM roles with the Principle of Least Privilege, and Security Groups restricted to necessary ports (80/443 for ALB, 5432 for DB).

Future Roadmap (Next Phase)

Automation (IaC)

Migrating this manual architecture to Terraform or AWS CloudFormation for one-click deployment.

CI/CD

Integrating with AWS CodePipeline for automated Django deployments.

Serverless

Evaluating AWS Lambda for background task processing to further reduce EC2 overhead.