What is Terraform?

You declare infrastructure (servers, networks, databases, and more) as code in .tf files, then create, update, or destroy real cloud resources with a single terraform apply. AWS, GCP, Azure, Kubernetes, and more are all supported.

Installation

Bash

# Ubuntu/Debian
wget -O- https://apt.releases.hashicorp.com/gpg | gpg --dearmor \
  | sudo tee /usr/share/keyrings/hashicorp-archive-keyring.gpg
echo "deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] \
  https://apt.releases.hashicorp.com $(lsb_release -cs) main" \
  | sudo tee /etc/apt/sources.list.d/hashicorp.list
sudo apt update && sudo apt install terraform

terraform version

Basic Structure

CODE

my-infra/
├── main.tf          # resource definitions
├── variables.tf     # input variables
├── outputs.tf       # output values
├── providers.tf     # provider configuration
└── terraform.tfvars # variable values (exclude from git)

AWS EC2 Example

providers.tf

HCL

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

provider "aws" {
  region = var.region
}

main.tf

HCL

data "aws_ami" "ubuntu" {
  most_recent = true
  owners      = ["099720109477"]

  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-*-22.04-amd64-server-*"]
  }
}

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

  tags = {
    Name        = "web-server"
    Environment = "production"
  }
}

outputs.tf

HCL

output "instance_public_ip" {
  value = aws_instance.web.public_ip
}

Workflow

Bash

# Initialize (download providers)
terraform init

# Review the execution plan (what will actually be created/changed/destroyed)
terraform plan

# Apply
terraform apply

# Apply a specific resource only
terraform apply -target=aws_instance.web

# Destroy everything
terraform destroy

# Inspect current state
terraform show
terraform state list

Remote State Management (Team Collaboration)

HCL

# backend.tf
terraform {
  backend "s3" {
    bucket         = "my-terraform-state"
    key            = "prod/terraform.tfstate"
    region         = "ap-northeast-2"
    encrypt        = true
    dynamodb_table = "terraform-lock"
  }
}

Always manage the state file (terraform.tfstate) in a remote backend (S3 + DynamoDB locking). Never commit it to git.

#Terraform#IaC#AWS#Infrastructure#DevOps

Editorial note

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Topic-related official docs (auto-linked · not per-claim sources)Terraform documentation ↗AWS documentation ↗

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Terraform Basics — Managing Infrastructure as Code