🏗️ Legacy System to AWS Migration (Lift-and-Shift + Modernization)

This project migrates a legacy on-premise web application to AWS using a Lift-and-Shift strategy, followed by partial modernization using cloud-native resources and Terraform automation.

🔧 Phases

Phase 1:

• VPC creation with public and private subnets
• Internet Gateway and route table configuration

Phase 2:

• EC2 instance deployment with Apache web server using a user data script
• Security groups for SSH/HTTP access
• Key pair usage for SSH access

Phase 3:

• RDS PostgreSQL database in a private subnet
• Security groups allowing RDS access only from EC2
• Variable-based infrastructure management

Phase 4:

• Outputs for EC2 public IP and RDS endpoint
• Connection verification from EC2 to RDS (Python/Postgres or CLI)

Phase 5:

• Planned: S3 bucket for static content, logs, and backups

💻 Tech Stack

• AWS EC2
• AWS RDS (PostgreSQL)
• AWS VPC/Subnetting
• AWS Security Groups
• Terraform (Infrastructure as Code)

✅ Outcomes

• Infrastructure fully provisioned with Terraform
• Secure architecture: EC2 in public, RDS in private
• Web server live via EC2 + Apache
• Database isolated and secured
• Reproducible and modular Terraform codebase

📂 File Structure

legacy-migration-terraform/
│
├── main.tf                  # AWS provider setup
├── provider.tf              # Terraform provider/version requirements
├── vpc.tf                   # VPC, subnets, routes, IGW
├── ec2.tf                   # EC2 instance + user_data
├── rds.tf                   # RDS PostgreSQL setup
├── security_groups.tf       # EC2 & RDS security groups
├── variables.tf             # Input variables
├── terraform.tfvars         # Variable values
├── outputs.tf               # Useful outputs (IP, endpoint)
├── README.md                # Project overview and instructions
└── .gitignore               # Ignore Terraform state & cache