This project provides a modular and scalable Terraform codebase for deploying AWS infrastructure components such as VPC, subnets, and remote state management using S3 and DynamoDB.

iac-aws-modular-infra/ ├── modules/ │ └── vpc/ │ ├── main.tf │ ├── variables.tf │ └── outputs.tf ├── environments/ │ └── dev/ │ ├── main.tf │ ├── terraform.tfvars │ └── backend.tf ├── .gitignore └── README.md

• 🔁 Reusable VPC module
• ☁️ Remote backend setup using S3 + DynamoDB
• 🌐 Public and private subnets support
• 🔒 Secure outputs and variables
• 🚀 Production-grade structure ready for EC2, EKS, RDS modules

• Terraform v1.5+
• AWS CLI
• S3 & DynamoDB (for backend)
• GitHub

git clone https://github.com/M-Inamdar/iac-aws-modular-infra.git
cd iac-aws-modular-infra/environments/dev

Modify backend.tf:

terraform {
  backend "s3" {
    bucket         = "your-terraform-bucket"
    key            = "dev/vpc/terraform.tfstate"
    region         = "ap-south-1"
    dynamodb_table = "terraform-locks"
    encrypt        = true
  }
}

Run:

terraform init

Edit terraform.tfvars:

region         = "ap-south-1"
vpc_cidr       = "10.0.0.0/16"
public_subnets = ["10.0.1.0/24", "10.0.2.0/24"]
private_subnets = ["10.0.101.0/24", "10.0.102.0/24"]

terraform plan
terraform apply

After terraform apply, the module will return:

VPC ID

Public/Private Subnet IDs

CIDR block references

Sample usage from main.tf:

module "vpc" {
  source          = "../../modules/vpc"
  region          = var.region
  vpc_cidr        = var.vpc_cidr
  public_subnets  = var.public_subnets
  private_subnets = var.private_subnets
}

Sample usage from main.tf in environments/dev:

module "ec2" {
  source             = "../../modules/ec2"
  ami_id             = var.ami_id
  instance_type      = var.instance_type
  key_name           = var.key_name
  subnet_id          = var.public_subnet_id
  security_group_ids = var.security_group_ids
}

Make sure these variables are defined in your terraform.tfvars:

ami_id             = "ami-020cba7c55df1f615"
instance_type      = "t2.micro"
key_name           = "your-key-pair-name"
public_subnet_id   = "subnet-xxxxxxxx"
security_group_ids = ["sg-xxxxxxxx"]

EC2 Instance ID

Public IP

Availability Zone

v1.0.0 – Modular VPC

v1.0.1 – Modular EC2 provisioning added

DevOps Architect | Cloud Infra Specialist