Infrastructure as Code (Terraform + AWS)

# Production-grade AWS Infrastructure
# Demonstrates IaC best practices with Terraform

terraform {
  required_version = ">= 1.0"
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
  backend "s3" {
    bucket = "terraform-state-bucket"
    key    = "prod/terraform.tfstate"
    region = "us-east-1"
    encrypt = true
  }
}

# VPC with public/private subnets
module "vpc" {
  source = "./modules/vpc"
  
  cidr_block           = "10.0.0.0/16"
  availability_zones   = ["us-east-1a", "us-east-1b"]
  public_subnets       = ["10.0.1.0/24", "10.0.2.0/24"]
  private_subnets      = ["10.0.10.0/24", "10.0.20.0/24"]
  enable_nat_gateway   = true
  enable_dns_hostnames = true
  
  tags = local.common_tags
}

# Application Load Balancer
module "alb" {
  source = "./modules/alb"
  
  vpc_id              = module.vpc.vpc_id
  public_subnets      = module.vpc.public_subnet_ids
  security_group_ids  = [module.security_groups.alb_sg_id]
  certificate_arn     = aws_acm_certificate.main.arn
  
  tags = local.common_tags
}

# Auto Scaling Group
module "asg" {
  source = "./modules/asg"
  
  vpc_id              = module.vpc.vpc_id
  private_subnets     = module.vpc.private_subnet_ids
  target_group_arns   = [module.alb.target_group_arn]
  security_group_ids  = [module.security_groups.app_sg_id]
  
  instance_type       = "t3.medium"
  min_size            = 2
  max_size            = 10
  desired_capacity    = 3
  
  tags = local.common_tags
}

# RDS Database (Multi-AZ)
module "rds" {
  source = "./modules/rds"
  
  vpc_id              = module.vpc.vpc_id
  private_subnets     = module.vpc.private_subnet_ids
  security_group_ids  = [module.security_groups.db_sg_id]
  
  engine              = "postgres"
  engine_version      = "15.3"
  instance_class      = "db.t3.large"
  allocated_storage   = 100
  multi_az            = true
  backup_retention    = 7
  
  tags = local.common_tags
}