Create AWS EC2 Instance With Key Pairs Using Terraform

Terraform has become one of my favorite tools I tried out recently. If you are reading this article, then I’m guessing you are already familiar with it. But if not, check out this 👉 introduction to get some basics first.

Write configuration

For this tutorial, we will primarily use 3 tf config files. Let’s create a dedicated directory to store them.

mkdir aws-ec2-with-key-pairs
cd aws-ec2-with-key-pairs

Now that we are in the directory, create the config files and open them on your favorite code editor. I’m using Visual Studio Code.

touch main.tf variable.tf output.tf
code .

variable.tf

This is where we will save our config variables which will be used in main.tf,

variable "instance-region" {
  description = "Value of AWS region"
  type        = string
  default     = "eu-central-1"
}

variable "instance-name" {
  description = "Value of the Name tag for the EC2 instance"
  type        = string
  default     = "OverEngineeredVPS"
}

variable "key-pair" {
  description = "Value of AWS SSH key-pair name"
  type        = string
  default     = "oei-key-pair"
}

main.tf

Let’s use the variables we set to create an EC2 instance.

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.16"
    }
  }

  required_version = ">= 1.2.0"
}

resource "tls_private_key" "oei-key" {
  algorithm = "RSA"
  rsa_bits  = 4096
}

resource "aws_key_pair" "oei-key-pair" {
  key_name = "oei-key-pair"
  public_key = tls_private_key.oei-key.public_key_openssh
}

provider "aws" {
  region = var.instance-region
}

resource "aws_instance" "oei-server" {
  ami           = "ami-09042b2f6d07d164a" // for frankfurt + ubuntu
  instance_type = "t2.small" // $0.023/H
  key_name      = "oei-key-pair"

  tags = {
    Name = var.instance-name
  }
}

Now if we run this file, it will create an ec2 server on eu-central-1(as we specified in variable.tf) with a key-pair called oei-key-pair. But if you wish to use a different location, make sure to change your ami value according to the AWS configuration.

output.tf

We will use this file to output the results on the console.

output "instance_id" {
  description = "ID of the EC2 instance"
  value       = aws_instance.oei-server.id
}

output "instance_public_ip" {
  description = "Public IP address of the EC2 instance"
  value       = aws_instance.oei-server.public_ip
}

output "instance_public_DNS" {
  description = "Public IP address of the EC2 instance"
  value       = aws_instance.oei-server.public_dns
}

output "instance_public_key" {
  description = "Public key of oe-key-pair"
  value       = tls_private_key.oei-key.public_key_openssh
  sensitive   = true
}

output "instance_private_key" {
  description = "Private key of oe-key-pair"
  value       =  tls_private_key.oei-key.private_key_pem
  sensitive   = true
}

Notice I used the sensitive flag on instance_public_key & instance_private_key so that it does not show the plain output by default.

Apply the configuration

Now that we have written our config file, let’s run these 👇🏼 commands to let Terraform do its job.

terraform init

This will download and install the AWS plugins for the providers we used. After the installation is done, run terraform plan to see the changes that will take place on the infrastructure. If everything looks alright, let’s apply the changes by running 👇🏼

terraform apply

This will take some time. But once it is done, you should be able to run terraform output to see the results we specified on output.tf.

To check the sensitive output, just run terraform output -raw “key name”. Example: 👇🏼

Conclusion

Thanks for reading the article guys. Hope it helped!