Multi-region AWS network with Transit Gateway peering

The problem

Workloads in Mumbai needed private, routable connectivity to a second region for resilience — defined as code, not clicked together in the console.

Approach

• Wrote reusable Terraform modules for VPCs, subnets, route tables and Transit Gateways.
• Connected ap-south-1 (Mumbai) and ap-south-2 (Hyderabad) with inter-region TGW peering.
• Kept per-region configuration in variables so environments are consistent.

Outcome

• The whole network can be recreated or extended from code.
• A second region ready for DR and latency-sensitive workloads.