🏗️ Terraform Modules — AWS VPC & EC2

AWS infrastructure using a modular Terraform structure with support for multiple environments (dev & production).

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📁 Project Structure

TERRAFORM-MODULES/
├── ENVS/
│   └── dev/
│       ├── main.tf           # Calls VPC & EC2 modules
│       ├── variables.tf      # Variable declarations
│       ├── provider.tf       # AWS provider config
│       ├── outputs.tf        # Shows vpc_id, subnet IDs, EC2 IP
│       └── dev.tfvars.example  # Example tfvars (actual dev.tfvars is gitignored)
│
└── MODULES/
    ├── VPC/
    │   ├── main.tf           # VPC, public & private subnets
    │   ├── variables.tf
    │   └── outputs.tf        # Exports vpc_id, subnet IDs
    └── EC2/
        ├── main.tf           # EC2 instance inside custom VPC
        ├── variables.tf
        └── outputs.tf

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🚀 What This Project Does

• Creates a custom AWS VPC with public and private subnets
• Launches an EC2 instance inside the custom VPC (not default VPC)
• Uses Terraform modules for reusable, clean infrastructure
• Currently has dev environment set up with full VPC + EC2 infrastructure

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🗺️ Architecture Diagram

⚙️ How It Works

dev.tfvars  →  dev/main.tf  →  VPC Module  →  outputs (subnet_id)
                           →  EC2 Module  ←  uses subnet_id from VPC

The dev/main.tf acts as a bridge — it passes values from dev.tfvars to both modules, and passes the VPC output (subnet ID) into the EC2 module.

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🛠️ Usage

1. Go to your environment folder

cd ENVS/dev

2. Create your tfvars file from example

# 
Look at dev.tfvars.example and create dev.tfvars with your own values
cp dev.tfvars.example dev.tfvars
# Now, put the actual values in dev.tfvars

3. Initialize Terraform

terraform init

3. Plan (preview changes)

terraform plan -var-file="dev.tfvars"

4. Apply (create infrastructure)

terraform apply -var-file="dev.tfvars"

5. Destroy (delete infrastructure)

terraform destroy -var-file="dev.tfvars"

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🔧 Want to Extend This Project?

This project is built to be easily expandable! Here are some things you can try:

Add a Production Environment:

ENVS/
└── production/
    ├── main.tf
    ├── variables.tf
    ├── provider.tf
    └── prod.tfvars    # Different CIDR, instance type, region etc.

Just copy the dev folder, rename to production, and update values in prod.tfvars!

Add More Modules:

MODULES/
├── RDS/       # Add a database
├── S3/        # Add storage buckets
├── ALB/       # Add a load balancer
└── SG/        # Add security groups as a module

Each module follows the same pattern — main.tf, variables.tf, and outputs.tf.

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📝 Variables (dev.tfvars.example)

⚠️ Note: dev.tfvars is not pushed to GitHub because it contains sensitive values like AMI IDs and environment-specific config. Instead, dev.tfvars.example is provided as a template. Copy it and fill in your own values.

cp dev.tfvars.example dev.tfvars

Variable	Description	Example
cidr-block	VPC CIDR range	10.0.0.0/16
public_cidr	Public subnet CIDR	10.0.1.0/24
private_cidr	Private subnet CIDR	10.0.2.0/24
availability_zone	AWS AZ	us-east-1a
ami_id	EC2 AMI ID	ami-0abc123...
instance_type	EC2 instance type	t3.micro
name	Resource name tag	Server
Name	VPC name tag	vpc_module

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📤 Outputs

After terraform apply, you will see:

• vpc_id — ID of the created VPC
• public_subnet_id — ID of the public subnet
• private_subnet_id — ID of the private subnet
• ec2_public_ip — Public IP of the EC2 instance
• ec2_public_dns — Public DNS of the EC2 instance

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🔑 Key Concepts Used

• Terraform Modules — Reusable infrastructure components
• Output Variables — Passing data between modules
• tfvars files — Environment-specific values
• Multi-environment setup — Dev is there but we can add production env also.

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