Terraform Basics

Terraform is an open-source infrastructure as code software tool that provides a consistent CLI workflow to manage hundreds of cloud services.

Core Concepts

Providers

Providers are plugins for interacting with cloud APIs. For this course:

terraform {
  required_providers {
    hcloud = {
      source = "hetznercloud/hcloud"
    }
  }
}

provider "hcloud" {
  # reads HCLOUD_TOKEN from environment
}

Resources

Each resource block maps to one infrastructure object.

resource "hcloud_server" "web" {
  name        = "web-1"
  server_type = "cx33"
  image       = "debian-13"
  location    = "nbg1"
}

Variables

Input variables serve as parameters for a Terraform module.

variable "instance_type" {
  description = "Type of EC2 instance"
  type        = string
  default     = "t3.micro"
}

Terraform Workflow

1. Write - Author infrastructure as code
2. Plan - Preview changes before applying
3. Apply - Provision reproducible infrastructure

terraform init
terraform plan
terraform apply

State Management

Terraform keeps track of your real world infrastructure in a state file. This state is used to create plans and make changes to your infrastructure.