Why Terraform?

Terraform enables declarative infrastructure management across multiple cloud providers. It provides consistency, repeatability, and collaboration through Infrastructure as Code.

Project Structure

infrastructure/
├── modules/
│   ├── networking/
│   │   ├── main.tf
│   │   ├── variables.tf
│   │   └── outputs.tf
│   ├── compute/
│   └── database/
├── environments/
│   ├── dev/
│   │   ├── main.tf
│   │   ├── terraform.tfvars
│   │   └── backend.tf
│   ├── staging/
│   └── prod/
└── global/
    └── iam/

State Management

Remote State

Always use remote state for team collaboration:

terraform {
  backend "s3" {
    bucket         = "company-terraform-state"
    key            = "prod/networking/terraform.tfstate"
    region         = "us-east-1"
    encrypt        = true
    dynamodb_table = "terraform-locks"
  }
}

State Locking

Use DynamoDB (AWS) or Azure Blob leases to prevent concurrent modifications.

State Isolation

Separate state files by environment and component:

states/
├── prod/networking/terraform.tfstate
├── prod/compute/terraform.tfstate
├── staging/networking/terraform.tfstate
└── staging/compute/terraform.tfstate

Module Best Practices

Module Design

// modules/networking/variables.tf
variable "vpc_cidr" {
  description = "CIDR block for VPC"
  type        = string
  
  validation {
    condition     = can(cidrhost(var.vpc_cidr, 0))
    error_message = "Must be a valid CIDR block."
  }
}

variable "environment" {
  description = "Environment name"
  type        = string
}

variable "tags" {
  description = "Tags to apply to resources"
  type        = map(string)
  default     = {}
}

Module Versioning

module "networking" {
  source  = "git::https://github.com/company/terraform-modules.git//networking?ref=v1.2.0"
  
  vpc_cidr    = "10.0.0.0/16"
  environment = "prod"
}

Code Quality

Formatting and Validation

# Format code
terraform fmt -recursive

# Validate configuration
terraform validate

# Security scanning
tfsec .

# Cost estimation
infracost breakdown --path .

Pre-commit Hooks

# .pre-commit-config.yaml
repos:
  - repo: https://github.com/antonbabenko/pre-commit-terraform
    hooks:
      - id: terraform_fmt
      - id: terraform_validate
      - id: terraform_tfsec

CI/CD Pipeline

# GitHub Actions example
jobs:
  terraform:
    steps:
      - uses: hashicorp/setup-terraform@v2
      - run: terraform init
      - run: terraform fmt -check
      - run: terraform validate
      - run: terraform plan -out=tfplan
      - run: terraform apply tfplan  # Only on main branch

Secrets Management

• Never commit secrets to version control
• Use environment variables or secret managers
• Reference secrets from Vault or AWS Secrets Manager

Conclusion

Following these best practices ensures your Terraform codebase remains maintainable, secure, and collaborative as your infrastructure grows.