Introduction

Terraform is an infrastructure-as-code tool that lets you define both cloud and on-prem resources in human-readable configuration files that you can version, reuse, and share. You can then use a consistent workflow to provision and manage all of your infrastructure throughout its lifecycle. Terraform can manage low-level components like compute, storage, and networking resources, as well as high-level components like DNS entries and SaaS features.

Terraform, developed by HashiCorp, allows you to define and provision cloud resources using simple, declarative configuration files. With Terraform, infrastructure becomes version-controlled, repeatable, and automated, making it a core tool for DevOps engineers and system administrators.

Prerequisites:

Before you begin, ensure the following requirements are met:

  • An active AWS account
  • An IAM user with:
    Programmatic access
    EC2, VPC, and Elastic IP permissions
  • Ubuntu Linux
  • Basic knowledge of:
    Linux commands
    AWS EC2 concepts
    SSH access

Install AWS CLI (Ubuntu)

Terraform uses AWS credentials configured via the AWS CLI to authenticate with AWS.

Step 1: Update System Packages

This step updates the local package index and installs required utilities (curl and unzip) that are needed to download and extract the AWS CLI installer.

apt update
apt install -y curl unzip

Step 2: Download AWS CLI v2

Download the official AWS CLI v2 installer package from AWS to the local system.

curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o awscliv2.zip

Step 3: Install AWS CLI

Extract the downloaded package and run the installation script to install AWS CLI v2 system-wide.

unzip awscliv2.zip
./aws/install

Step 4: Verify Installation

Confirm that AWS CLI is installed successfully and check the installed version.

aws --version

Configure AWS Credentials

Run the following command and provide your IAM credentials:

aws configure

Enter:

  • AWS Access Key ID
  • AWS Secret Access Key
  • Default region name: ap-south-1
  • Default output format:json

Install Terraform

Step 1: Add HashiCorp Repository

Add HashiCorp’s official GPG key and repository so Terraform can be installed and updated securely using apt.

wget -O - https://apt.releases.hashicorp.com/gpg | sudo gpg --dearmor -o /usr/share/keyrings/hashicorp-archive-keyring.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] https://apt.releases.hashicorp.com $(grep -oP '(?<=UBUNTU_CODENAME=).*' /etc/os-release || lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/hashicorp.list
sudo apt update && sudo apt install terraform

Step 2: Install Terraform

Update the package list and install Terraform from the official HashiCorp repository.

apt update
apt install terraform -y

Step 3: Verify Installation

Verify that Terraform is installed correctly by checking its version.

terraform -v

Terraform Project Structure

Create a dedicated project directory:

mkdir terraform-ec2 && cd terraform-ec2

Project structure:

terraform-ec2/
├── provider.tf
├── variables.tf
├── main.tf
├── outputs.tf

Terraform Configuration Files

provider.tf

provider “aws” {
region = “ap-south-1”
}

variables.tf

variable “ami_id” {
default = “ami-0f5ee92e2d63afc18”
}
variable “instance_type” {
default = “t2.micro”
}
variable “key_name” {
default = “my-keypair”
}

main.tf

resource “aws_security_group” “ec2_sg” {
name = “terraform-sg”
ingress {
from_port = 22
to_port = 22
protocol = “tcp”
cidr_blocks = [“0.0.0.0/0”]
}
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”]
}
}
resource “aws_instance” “ec2” {
ami = var.ami_id
instance_type = var.instance_type
key_name = var.key_name
vpc_security_group_ids = [aws_security_group.ec2_sg.id]
tags = {
Name = “Terraform-EC2”
}
}
resource “aws_eip” “eip” {
instance = aws_instance.ec2.id
}

outputs.tf

output “public_ip” {
value = aws_eip.eip.public_ip
}

Deploy the Infrastructure

Initialize Terraform:

terraform init

Preview the execution plan:

terraform plan

Apply the configuration:

terraform apply

Type yes when prompted.

Verification

  1. Login to AWS Console
  2. Navigate to EC2 → Instances
  3. Verify:
    Instance is running
    Security group is attached
    Elastic IP is assigned

SSH Access

Use the private key (.pem file) associated with your EC2 instance to establish an SSH connection.

ssh -i my-keypair.pem ubuntu@<Elastic-IP>

Cleanup Resources

To avoid unnecessary AWS charges, destroy all resources when no longer needed:

terraform destroy

Conclusion:

Terraform simplifies cloud infrastructure management by enabling automation, consistency, and scalability. In this guide, we successfully created an AWS EC2 instance using Terraform, complete with security groups and an Elastic IP.

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