Terraform

TL;DR

Quoi : Un outil d’infrastructure as code pour provisionner des ressources cloud.

Pourquoi : Syntaxe déclarative, multi-cloud, gestion d’état, infrastructure reproductible.

Quick Start

Installer :

brew install terraform  # macOS
# or download from terraform.io

Create main.tf :

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

provider "aws" {
  region = "us-east-1"
}

resource "aws_instance" "example" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"

  tags = {
    Name = "example-instance"
  }
}

Exécuter :

terraform init
terraform plan
terraform apply

Cheatsheet

Commande	Description
terraform init	Initialiser le répertoire de travail
terraform plan	Prévisualiser les changements
terraform apply	Appliquer les changements
terraform destroy	Détruire l’infrastructure
terraform fmt	Formater le code
terraform validate	Valider la configuration
terraform output	Afficher les outputs
terraform state list	Lister les ressources dans l’état

Gotchas

Variables

# variables.tf
variable "instance_type" {
  description = "EC2 instance type"
  type        = string
  default     = "t2.micro"
}

# main.tf
resource "aws_instance" "example" {
  instance_type = var.instance_type
}

# terraform.tfvars
instance_type = "t3.small"

Outputs

output "instance_ip" {
  value       = aws_instance.example.public_ip
  description = "Public IP of the instance"
}

Data sources

data "aws_ami" "ubuntu" {
  most_recent = true
  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-focal-20.04-amd64-server-*"]
  }
  owners = ["099720109477"]
}

resource "aws_instance" "example" {
  ami = data.aws_ami.ubuntu.id
}

Modules

module "vpc" {
  source  = "terraform-aws-modules/vpc/aws"
  version = "5.0.0"

  name = "my-vpc"
  cidr = "10.0.0.0/16"
}

Next Steps

• Terraform Documentation - Documentation officielle
• Terraform Registry - Providers et modules
• Terraform Tutorials - Apprendre
• Terraform Best Practices - Bonnes pratiques