infra-as-code

# Infrastructure as Code

Define, deploy, and manage cloud infrastructure using declarative configuration. Covers Terraform (multi-cloud), AWS CloudFormation, and Pulumi (code-first), with patterns for compute, networking, storage, databases, and state management.

## When to Use

- Setting up cloud infrastructure (VPCs, EC2, Lambda, S3, RDS, etc.)
- Writing or modifying Terraform configurations
- Managing Terraform state (remote backends, workspaces, imports)
- Creating CloudFormation templates
- Using Pulumi for infrastructure in TypeScript/Python/Go
- Planning and previewing infrastructure changes safely
- Debugging drift between declared state and actual resources
- Setting up multi-environment deployments (dev/staging/prod)

## Terraform

### Quick Start

```bash
# Install: https://developer.hashicorp.com/terraform/install

# Initialize a project
mkdir infra && cd infra
terraform init

# Core workflow
terraform plan        # Preview changes (safe, read-only)
terraform apply       # Apply changes (creates/modifies resources)
terraform destroy     # Tear down all resources

# Format and validate
terraform fmt -recursive    # Auto-format all .tf files
terraform validate          # Check syntax and config validity
```

### Project Structure

```
infra/
  main.tf              # Primary resources
  variables.tf         # Input variable declarations
  outputs.tf           # Output values
  providers.tf         # Provider configuration
  terraform.tfvars     # Variable values (don't commit secrets)
  backend.tf           # Remote state configuration
  modules/
    vpc/
      main.tf
      variables.tf
      outputs.tf
    compute/
      main.tf
      variables.tf
      outputs.tf
```

### Provider Configuration

```hcl
# providers.tf
terraform {
  required_version = ">= 1.5"
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

provider "aws" {
  region = var.aws_region

  default_tags {
    tags = {
      Project...