Terraform Complete Guide 2025 - Infrastructure as Code Tutorial

🚀 Why Terraform in 2025?

Terraform by HashiCorp remains the #1 Infrastructure as Code (IaC) tool with 85% market share. In 2025, it's essential for cloud-native, multi-cloud, and hybrid infrastructure management.

📦 Installation in 2 Minutes

# Linux/Mac
wget https://releases.hashicorp.com/terraform/1.6.0/terraform_1.6.0_linux_amd64.zip
unzip terraform_1.6.0_linux_amd64.zip
sudo mv terraform /usr/local/bin/

# Verify
terraform version

🎯 Your First Terraform Configuration

Create main.tf:

terraform {
  required_version = ">= 1.6.0"
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

provider "aws" {
  region = "ap-south-1"
}

resource "aws_instance" "web_server" {
  ami           = "ami-0f5ee92e2d63afc18"
  instance_type = "t2.micro"

  tags = {
    Name = "MyFirstTerraformInstance"
  }
}

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

🔧 Essential Commands

terraform init          # Initialize & download providers
terraform validate      # Validate configuration
terraform plan          # Preview changes
terraform apply         # Apply configuration
terraform destroy       # Destroy infrastructure
terraform state list    # List resources

📁 Core Concepts

🏗️ Real-World Example: Complete AWS Setup

# variables.tf
variable "environment" {
  default = "production"
}

# main.tf
resource "aws_vpc" "main" {
  cidr_block = "10.0.0.0/16"

  tags = {
    Name = "${{var.environment}}  -vpc"
  }
}

resource "aws_subnet" "public" {
  vpc_id     = aws_vpc.main.id
  cidr_block = "10.0.1.0/24"

  tags = {
    Name = "${{var.environment}}  -public-subnet"
  }
}

resource "aws_security_group" "web" {
  name        = "web-sg"
  description = "Allow HTTP/HTTPS"
  vpc_id      = aws_vpc.main.id

  ingress {
    from_port   = 80
    to_port     = 80
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

🔄 Modules: Reusable Components

# Create module
# modules/ec2/main.tf
resource "aws_instance" "server" {
  # Configuration
}

# Use module
module "web_server" {
  source = "./modules/ec2"

  instance_type = "t3.medium"
  environment   = "production"
}

🔐 Security Best Practices

# Use environment variables for secrets
# Don't hardcode credentials!

variable "aws_access_key" {
  type = string
}

variable "aws_secret_key" {
  type      = string
  sensitive = true  # Marks as sensitive
}

# Backend configuration (remote state)
terraform {
  backend "s3" {
    bucket = "my-terraform-state"
    key    = "production/terraform.tfstate"
    region = "ap-south-1"
    encrypt = true
  }
}

🚀 Advanced Features 2025

1. Workspaces: Environment management

terraform workspace new staging
terraform workspace select production

2. Dynamic Blocks: Conditional configurations

dynamic "ingress" {
  for_each = var.open_ports
  content {
    from_port   = ingress.value
    to_port     = ingress.value
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

3. Terraform Cloud: Collaboration platform

terraform {
  cloud {
    organization = "my-org"
    workspaces {
      name = "production"
    }
  }
}

📊 Career Impact 2025

🎯 Learning Roadmap

Start now: Your infrastructure as code journey begins with terraform init!

Remember: Terraform isn't just a tool - it's a mindset shift toward reproducible, version-controlled infrastructure.