Skip to content

Terraform Basics.md

Latest commit

 

History

History
279 lines (225 loc) · 7.34 KB

Terraform Basics.md

File metadata and controls

279 lines (225 loc) · 7.34 KB
Raw

🏗️ Terraform Basics

Last updated: February 1, 2026

A practical introduction to Terraform for beginners—Infrastructure as Code fundamentals.

Intro • Install • Configuration • Commands • Examples • Best Practices • Resources

📖 What is Terraform?

Terraform is an open-source Infrastructure as Code (IaC) tool created by HashiCorp. It allows you to define and provision cloud infrastructure using declarative configuration files.

Key Benefits:

  • Define infrastructure in version-controllable code
  • Plan changes before applying them
  • Manage infrastructure across AWS, Azure, Google Cloud, and more
  • Enable team collaboration and reproducibility

⚙️ Installation

  1. Download the latest version from the Terraform downloads page.
  2. Extract the binary and add it to your system PATH.
  3. Verify installation:
terraform --version

📝 Configuration Structure

File Organization

Create a working directory and add these standard files:

project/
├── main.tf           # Primary configuration
├── variables.tf      # Input variables
├── outputs.tf        # Output values
├── terraform.tfvars  # Variable values
└── .gitignore        # Exclude sensitive files

Basic Example

# main.tf
terraform {
  required_version = ">= 1.0"
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.0"
    }
  }
}

provider "aws" {
  region = var.aws_region
}

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

  tags = {
    Name = var.instance_name
  }
}
# variables.tf
variable "aws_region" {
  description = "AWS region"
  type        = string
  default     = "us-west-2"
}

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

variable "instance_name" {
  description = "Name of the instance"
  type        = string
}

🎯 Core Commands

Command Description
terraform init Initialize working directory, download providers
terraform plan Preview changes without applying them
terraform apply Apply configuration changes to cloud
terraform destroy Destroy all managed infrastructure
terraform fmt Format code to standard style
terraform validate Check configuration syntax
terraform import Import existing resources into state
terraform state Manage Terraform state file

📋 Practical Examples

Example 1: AWS EC2 Instance

provider "aws" {
    region = "us-west-2"
}

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

Example 2: AWS S3 Bucket

resource "aws_s3_bucket" "example" {
  bucket = "my-unique-bucket-name"

  tags = {
    Environment = "production"
  }
}

resource "aws_s3_bucket_versioning" "example" {
  bucket = aws_s3_bucket.example.id
  versioning_configuration {
    status = "Enabled"
  }
}

resource "aws_s3_bucket_server_side_encryption_configuration" "example" {
  bucket = aws_s3_bucket.example.id

  rule {
    apply_server_side_encryption_by_default {
      sse_algorithm = "AES256"
    }
  }
}

Example 3: Azure Virtual Machine

provider "azurerm" {
    features {}
}

resource "azurerm_resource_group" "example" {
    name     = "example-resources"
    location = "West US"
}

resource "azurerm_virtual_network" "example" {
    name                = "example-network"
    address_space       = ["10.0.0.0/16"]
    location            = azurerm_resource_group.example.location
    resource_group_name = azurerm_resource_group.example.name
}

resource "azurerm_subnet" "example" {
    name                 = "example-subnet"
    resource_group_name  = azurerm_resource_group.example.name
    virtual_network_name = azurerm_virtual_network.example.name
    address_prefixes     = ["10.0.2.0/24"]
}

resource "azurerm_network_interface" "example" {
    name                = "example-nic"
    location            = azurerm_resource_group.example.location
    resource_group_name = azurerm_resource_group.example.name

    ip_configuration {
        name                          = "internal"
        subnet_id                     = azurerm_subnet.example.id
        private_ip_address_allocation = "Dynamic"
    }
}

resource "azurerm_virtual_machine" "example" {
    name                  = "example-machine"
    location              = azurerm_resource_group.example.location
    resource_group_name   = azurerm_resource_group.example.name
    network_interface_ids = [azurerm_network_interface.example.id]
    vm_size               = "Standard_DS1_v2"

    storage_os_disk {
        name              = "example-os-disk"
        caching           = "ReadWrite"
        create_option     = "FromImage"
        managed_disk_type = "Standard_LRS"
    }

    storage_image_reference {
        publisher = "Canonical"
        offer     = "UbuntuServer"
        sku       = "18.04-LTS"
        version   = "latest"
    }

    os_profile {
        computer_name  = "example-machine"
        admin_username = "adminuser"
        admin_password = "Password1234!"
    }

    os_profile_linux_config {
        disable_password_authentication = false
    }
}

Example 4: Google Cloud Storage Bucket

provider "google" {
    project = "my-gcp-project"
    region  = "us-central1"
}

resource "google_storage_bucket" "example" {
    name     = "my-unique-bucket-name"
    location = "US"
}

🎓 Best Practices

  • ✅ Use version control — commit all Terraform files to Git
  • ✅ Separate state files — use remote backends for team collaboration
  • ✅ Plan before apply — always review terraform plan output
  • ✅ Use variables — avoid hardcoding values; use variables.tf
  • ✅ Organize with modules — break complex configurations into reusable modules
  • ✅ Name resources clearly — use consistent naming conventions
  • ✅ Add comments — document complex logic and resource purposes
  • ✅ Enable state locking — prevent concurrent modifications
  • ✅ Use terraform.tfvars — keep secrets out of version control
  • ✅ Validate early — run terraform validate and terraform fmt before committing

📚 Resources

Back to Student Resources