Module 27: What is Terraform

 What is Terraform 

Hashicorp's Terraform is an open-source tool for provisioning and managing cloud infrastructure. Terraform can provision resources on any cloud platform. 

Terraform allows you to create infrastructure in configuration files(tf files) that describe the topology of cloud resources. These resources include virtual machines, storage accounts, and networking interfaces.

 

We will see how you can use Terraform to provision EC2 instance. Please do the below steps for provisioning EC2 instances on AWS Linux 2

Watch the steps in YouTube channel: 

Pre-requistes:

1. Install AWS CLI first on your MAC or your EC2 instance.

Install yum-config-manager to manage your repositories.

$ sudo yum install -y yum-utils

Use yum-config-manager to add the official HashiCorp Linux repository.

$ sudo yum-config-manager --add-repo https://rpm.releases.hashicorp.com/AmazonLinux/hashicorp.repo

Install.

$ sudo yum -y install terraform

TIP: Now that you have added the HashiCorp repository, you can install Vault, Consul, Nomad and Packer with the same command.

»Verify the installation

Verify that the installation worked by opening a new terminal session and listing Terraform's available subcommands.

$ terraform -help
Usage: terraform [-version] [-help] <command> [args]

The available commands for execution are listed below.
The most common, useful commands are shown first, followed by
less common or more advanced commands. If you're just getting
started with Terraform, stick with the common commands. For the
other commands, please read the help and docs before usage.
##...

Add any subcommand to terraform -help to learn more about what it does and available options.

$ terraform -help plan

Install or update the AWS CLI

Follow these steps from the command line to install the AWS CLI on Linux.

We provide the steps in one easy to copy and paste group based on whether you use 64-bit Linux or Linux ARM. See the descriptions of each line in the steps that follow.

• Linux x86 (64-bit)
• Linux ARM

$ curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "awscliv2.zip"
unzip awscliv2.zip
sudo ./aws/install

2. Create a new access key if you don't have one. Make sure you download the keys in your local machine. Login to AWS console, click on username and go to My security credentials.

 Continue on security credentials, click on access keys

Perform below commands in MacOS/EC2 where you have installed Terraform:

First setup your access keys, secret keys and region code locally.

aws configure

cd ~

mkdir project-terraform

cd project-terraform

Create Terraform Files

sudo vi variables.tf

variable "aws_region" {

  description = "The AWS region to create things in."

  default     = "us-east-2"

}

variable "key_name" {

  description = " SSH keys to connect to ec2 instance"

  default     =  "your_pem_keyname"

}

variable "instance_type" {

  description = "instance type for ec2"

  default     =  "t2.micro"

}

Now create main.tf file

sudo vi main.tf

provider "aws" {

  region = var.aws_region

}

#Create security group with firewall rules

resource "aws_security_group" "security_jenkins_port" {

  name        = "security_jenkins_port"

  description = "security group for jenkins"

  ingress {

    from_port   = 8080

    to_port     = 8080

    protocol    = "tcp"

    cidr_blocks = ["0.0.0.0/0"]

  }

 ingress {

    from_port   = 22

    to_port     = 22

    protocol    = "tcp"

    cidr_blocks = ["0.0.0.0/0"]

  }

 # outbound from jenkis server

  egress {

    from_port   = 0

    to_port     = 65535

    protocol    = "tcp"

    cidr_blocks = ["0.0.0.0/0"]

  }

  tags= {

    Name = "security_jenkins_port"

  }

}

resource "aws_instance" "myFirstInstance" {

  ami           = "ami-0b9064170e32bde34"

  key_name = var.key_name

  instance_type = var.instance_type

  security_groups= [ "security_jenkins_port"]

  tags= {

    Name = "jenkins_instance"

  }

}

# Create Elastic IP address

resource "aws_eip" "myFirstInstance" {

  vpc      = true

  instance = aws_instance.myFirstInstance.id

tags= {

    Name = "jenkins_elstic_ip"

  }

}

Now execute the below command:

terraform init

you should see like below screenshot.

Execute the below command

terraform plan

the above command will show how many resources will be added.

Plan: 3 to add, 0 to change, 0 to destroy.

Execute the below command

terraform apply

Plan: 3 to add, 0 to change, 0 to destroy.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

Apply complete! Resources: 3 added, 0 changed, 0 destroyed.

Now login to EC2 console, to see the new instances up and running

List Resources created by Terraform

Execute the below command to view list of the resources created by Terraform.

terraform state list

The above command will list three resources created.

You should be able to see EC2 instance up and running in AWS console.