Building Multi-Region VPC Peering on AWS using Terraform | Mini Project
In this mini project, I explored one of the most important networking concepts in AWS — VPC Peering.
The goal was to establish private communication between multiple VPCs located in different AWS regions using Terraform Infrastructure as Code (IaC).
Instead of creating only two VPCs, I extended the project further by adding a third VPC, subnet, EC2 instance, and all required networking components, then established additional VPC peering connections to understand how multiple VPC networks can communicate securely using private IP addresses.
Architecture Overview
The architecture consists of three independent VPC environments:
Primary VPC (us-east-1)
CIDR Block:
10.0.0.0/16Public subnet with EC2 instance
Internet Gateway for internet connectivity
Secondary VPC (us-west-2)
CIDR Block:
10.1.0.0/16Public subnet with EC2 instance
Internet Gateway for internet connectivity
Third VPC
Separate CIDR block with its own subnet and EC2 instance
Configured with its own route tables, security groups, and internet access
Peered with the Primary VPC
VPC Peering Connections Implemented
I configured multiple VPC peering connections:
✅ Primary VPC ↔ Secondary VPC (Cross-region peering)
✅ Primary VPC ↔ Third VPC
Each peering connection was configured with:
Proper requester and accepter configuration
Non-overlapping CIDR ranges
Route table updates for private traffic routing
Security group rules allowing communication between VPCs
AWS Resources Created
Networking Resources
3 VPCs
3 Public Subnets
3 Internet Gateways
Multiple Route Tables
VPC Peering Connections
Security Groups with cross-VPC communication rules
Compute Resources
Amazon Linux 2 EC2 instances in each VPC
Apache Web Server installation
Custom web pages displaying VPC information
Security Configuration
Security groups were configured to allow:
SSH access (
Port 22) for administrationICMP traffic for ping testing
TCP traffic between peered VPC CIDR blocks
Outbound internet access through appropriate egress rules
Multi-Region Deployment using Terraform
One of the biggest learnings from this project was managing infrastructure across multiple AWS regions.
Terraform provider aliases were used to manage resources in different regions such as:
us-east-1us-west-2
This helped in understanding:
Multi-region infrastructure management
Cross-region dependencies
Region-specific resources such as AMIs and networking components
Project Demonstration
EC2 Instances Across Regions
This verifies successful deployment of compute resources across multiple regions.
VPC Peering Connection
The peering status should be Active, confirming that AWS has successfully established private connectivity between the VPCs.
Connectivity Testing
To validate VPC peering, I tested communication using private IP addresses.
Ping Test
Successful ICMP responses confirm that routing tables, security groups, and peering connections are configured correctly.
HTTP Communication Test
Using curl commands, I verified that Apache web servers hosted in remote VPCs were reachable through private network communication.
Important Concepts Learned
VPC Peering is Non-Transitive
A critical learning from this project is that VPC peering does not support transitive routing.
For example:
VPC A ↔ VPC B
VPC A ↔ VPC C
This does not mean:
VPC B ↔ VPC C
Traffic cannot automatically pass through VPC A to reach another peered VPC. A direct peering connection or another networking solution (such as Transit Gateway) is required.
Cost Considerations
This project creates billable AWS resources:
EC2 instances
VPC peering data transfer between regions
Public IP related charges (if applicable)
Always destroy the resources after testing to avoid unnecessary AWS charges:
terraform destroy
Key Learnings
Through this mini project, I gained hands-on experience with:
✅ Creating VPCs, subnets, and internet gateways using Terraform
✅ Configuring cross-region VPC peering
✅ Managing routing between private networks
✅ Designing security group rules for inter-VPC communication
✅ Deploying EC2 instances across multiple AWS regions
✅ Using Terraform provider aliases for multi-region infrastructure
✅ Testing private connectivity using ping and HTTP requests
✅ Understanding limitations of VPC peering and non-transitive routing
Resources That Helped Me Learn
The official Terraform and AWS documentation, along with YouTube hands-on tutorials, helped me understand VPC networking, peering concepts, and practical implementation using Terraform.
Connect With Me
LinkedIn: https://www.linkedin.com/in/devops-samarjeet/
I will continue documenting my hands-on journey of learning AWS, Terraform, and DevOps through real-world projects and practical implementations.
