Terraform Complete Guide — Infrastructure as Code

Terraform enables infrastructure provisioning through code, managing cloud resources declaratively.

Introduction

Terraform uses HCL to define infrastructure, enabling version-controlled, repeatable deployments.

Terraform Complete Guide — Infrastructure as Code
Basic Configuration
State Management
Modules
FAQ

Basic Configuration

terraform {
  required_version = ">= 1.0"
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

provider "aws" {
  region = var.aws_region
}

resource "aws_instance" "web" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = var.instance_type

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

variable "aws_region" {
  default = "us-east-1"
}

variable "instance_type" {
  default = "t3.micro"
}

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

State Management

# Initialize
terraform init

# Plan
terraform plan -out=tfplan

# Apply
terraform apply tfplan

# Show state
terraform show

# Remote state
terraform init -backend-config="bucket=my-terraform-state"

Modules

module "vpc" {
  source = "./modules/vpc"

  vpc_cidr = "10.0.0.0/16"
  environment = "production"
}

module "eks" {
  source = "terraform-aws-modules/eks/aws"
  version = "19.0.0"

  cluster_name    = "my-cluster"
  cluster_version = "1.27"
  vpc_id          = module.vpc.vpc_id
  subnet_ids      = module.vpc.private_subnets
}

FAQ

Q: What is Terraform state? A: State file tracking real infrastructure. Critical for tracking resources.

Q: Should I commit tfstate to Git? A: No. Use remote backend (S3, Terraform Cloud) for shared state.