Infra as code (IaC) is an essential concept in DevOps, allowing infra management in an automated and reproducible way. Terraform, developed by HashiCorp, is one of the most popular tools for this purpose.

In this post, we will explore the basic concepts of Terraform and go through a practical example of how to use it to create an instance on aws.

What is Terraform?

Terraform is an open-source tool for defining, provisioning, and managing infrastructure across multiple cloud providers (AWS, Azure, GCP, etc.) using a declarative configuration language called HCL (HashiCorp Configuration Language).

Key Features:

Multi-platform: Supports various providers such as AWS, Azure, GCP, Kubernetes, Etc.
Declarative: You define the desired state of the infra, and Terraform takes care of the necessary changes.
State management: Maintains a state file to track provisioned resources.
Plan and Apply: Allows you to preview changes before applying them.

Installing Terraform

Before getting started, install Terraform by following the instructions on the official site.

To verify the installation, run:
terraform --version

If Terraform is installed correctly, the version number will be displayed in the terminal.

Creating a Terraform Project

Now, leet's go through a practical example using AWS.

Initializing the Project

Create a directory for the project and navigate into it:
mkdir my-terraform-project && cd my-terraform-project

Create a file named main.tf and add the following basic configuration:

provider "aws" {
  region = "us-east-1"
}

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

Understanding the `main.tf` File

In terraform, configuration is divided into blocks, with the most common being:

Provider: Defines the cloud provider to be used. In the example above, we are using aws and specifying the region us-east-1.
Resources: Specifies the resource to be created. In this case, an EC2 instance (aws_instance).
- ami: ID of the operating system image to be used.
- instance_type: Type of instance (e.g., t2.micro, ideal for testing).
- tags: Labels applied to the instance for easier identification.

Initializing Terraform

In the terminal, run: terraform init
This command downloads the necessary plugins for the configured provider(in this case, AWS).

Planning Changes

Before creating resources, check what modifications will be applied: terraform plan
This displays the planned changes for the infrastructure.

Applying the Configuration

To create the instance on AWS, run: terraform apply
Type yes when prompted. After a few minutes, your instance will be created.

Destroying Resources

If you want to remove the created resources, user: terraform destroy
This prevents unnecessary cloud infrastructure costs.

Using Terraform with Docker

In addition to cloud providers, Terraform can also be used to manage Docker containers. Let's see a basic example.

Configuring a Container with terraform

Create a new file called docker.tf and add:

terraform {
    required_providers {
        docker = {
            source = "kreuzwerker/docker"
            version = "~> 2.13.0"
        }
    }
}

provider "docker" {
  host = "unix:///var/run/docker.sock"
}

resource "docker_image" "nginx" {
  name = "nginx:latest"
  keep_locally = false
}

resource "docker_container" "nginx" {
  image = docker_image.nginx.repo_digest
  name = "nginx"
  ports {
    internal = 80
    external = 8080
  }
}

Initializing and Applying the Configuration

Now, execute the following commands to start Terraform and create the container:

terraform init
terraform apply

Type yes when prompted. This will download the Nginx image and create a container exposed on port 8080.

Testing the Container

Once Terraform finishes, open http://localhost:8080 in your browser to see Nginx running.

Removing the Container

If you want to remove the created containers and images, run: terraform destroy
This will remove all resources created by Terraform.

Conclusion

Terraform simplifies infrastructure management by allowing you to define everything as code. It is ideal for scalable and reproducible environments.

In this post, we covered:

What Terraform is and why to use it.
How to install and configure a basic project.
How to create and manage resources on AWS.
A basic understanding of provider and resource blocks in Terraform.
How to use Terraform to manage Docker containers.

If you want to deepen your knowledge, I recommended check out the official Terraform documentation.

Did you like this content? Leave a comment or share your experience with Terraform! 🚀

Introduction to Terraform: Infra as Code in Practice