🧾 Terraform Cheat Sheet: The Ultimate Reference for Infrastructure as Code (2025)

Learn and master Terraform with this complete cheat sheet — from basics to advanced automation.

🚀 What is Terraform?

Terraform by HashiCorp is a declarative Infrastructure as Code (IaC) tool that allows you to provision, manage, and destroy infrastructure using human-readable configuration files.

In short: you write .tf code to define your cloud infrastructure, and Terraform makes it real — across AWS, Azure, GCP, and more.

📁 Typical Terraform Project Structure

my-project/
├── main.tf          # Core infrastructure code
├── variables.tf     # Variable declarations
├── outputs.tf       # Outputs (e.g., public IPs)
├── terraform.tfvars # Actual variable values
├── backend.tf       # Remote backend config (S3, Terraform Cloud)

⚙️ Common Terraform Commands

📘 Terraform Configuration Syntax (HCL)

🔹 1. Providers

provider "aws" {
  region = var.region
}

🔹 2. Resources

resource "aws_instance" "web" {
  ami           = var.ami_id
  instance_type = "t2.micro"
}

🔹 3. Variables

variable "region" {
  description = "AWS Region"
  type        = string
  default     = "us-east-1"
}

Use in code:

region = var.region

🔹 4. Outputs

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

🔹 5. Locals

locals {
  name_tag = "web-${var.environment}"
}

📦 Remote Backends (S3 Example)

terraform {
  backend "s3" {
    bucket         = "my-tf-state"
    key            = "env/dev/terraform.tfstate"
    region         = "us-east-1"
    dynamodb_table = "tf-locks"
  }
}

📦 Modules (Reusable Blocks)

module "vpc" {
  source     = "terraform-aws-modules/vpc/aws"
  name       = "my-vpc"
  cidr_block = "10.0.0.0/16"
}

🔐 Security Best Practices

🧪 Testing Terraform

🔄 Useful Patterns & Snippets

🔸 Conditional Logic

resource "aws_instance" "web" {
  count = var.create_instance ? 1 : 0
}

🔸 Dynamic Blocks

resource "aws_security_group" "example" {
  dynamic "ingress" {
    for_each = var.ingress_rules
    content {
      from_port   = ingress.value.from_port
      to_port     = ingress.value.to_port
      protocol    = ingress.value.protocol
      cidr_blocks = ingress.value.cidr_blocks
    }
  }
}

🔸 Workspaces

terraform workspace list
terraform workspace new staging
terraform workspace select staging

🧠 Best Practices

✅ Use terraform plan before every apply
✅ Format code using terraform fmt
✅ Commit .tf files, NOT .tfstate
✅ Store state in a remote backend with locking
✅ Use modules to avoid repetition
✅ Protect secrets (NEVER hardcode passwords in .tf files)

📚 Recommended Resources

🏁 Final Thoughts

Terraform isn’t just an IaC tool — it’s an ecosystem.
Learning to use it well will let you:

• Automate cloud provisioning
• Create reproducible environments
• Build infrastructure pipelines
• Work in real enterprise cloud projects

Treat infrastructure like code, version it, review it, test it — that’s Terraform magic.

Mohammad Gufran Jahangir