Building Infrastructure with Terraform

Terraform is similar to Amazon Cloud Formation. It allows you to automate the creation of your infrastructure like VPCs, ELBS, ASGs, Instances. Terraform is generic, it works with other provides besides AWS like containers and even bare-metal servers. Terraform build infrastructure, but also launch it as well.

Terraform enables infrastructure as a Code because you can describe your whole infrastructure with a simple set of declarative files. Terraform keeps track of state, so will tell you if can do something or can't do some operation. This is very cool for operation point of view. To use Terraform you just need to download the binaries for your OS and them put Terraform in your PATH. Once you have the config files you can do $ terraform apply and the magic will happen :-)

Today i will show how to build a very simple infrastructure on AWS, you just need have your credential(ID and Secret).  Main.tf is your config for the infrastructure. Variables are var you can use into your main and outputs is what terraform will output for you when its done. Download all this 3 scripts put into terraform folder, drop you pem file as well and just run $ terraform apply.
main.tf

	# Specify the provider and access details
	provider "aws" {
	region = "${var.aws_region}"
	}
	# Our default security group to access
	# the instances over SSH and HTTP
	resource "aws_security_group" "default" {
	name = "terraform_example"
	description = "Used in the terraform"
	# SSH access from anywhere
	ingress {
	from_port = 22
	to_port = 22
	protocol = "tcp"
	cidr_blocks = ["0.0.0.0/0"]
	}
	# HTTP access from anywhere
	ingress {
	from_port = 80
	to_port = 80
	protocol = "tcp"
	cidr_blocks = ["0.0.0.0/0"]
	}
	# outbound internet access
	egress {
	from_port = 0
	to_port = 0
	protocol = "-1"
	cidr_blocks = ["0.0.0.0/0"]
	}
	}
	resource "aws_elb" "web" {
	name = "terraform-example-elb"
	# The same availability zone as our instance
	availability_zones = ["${aws_instance.web.availability_zone}"]
	listener {
	instance_port = 80
	instance_protocol = "http"
	lb_port = 80
	lb_protocol = "http"
	}
	# The instance is registered automatically
	instances = ["${aws_instance.web.id}"]
	}
	resource "aws_instance" "web" {
	# The connection block tells our provisioner how to
	# communicate with the resource (instance)
	connection {
	# The default username for our AMI
	user = "ubuntu"
	# The path to your keyfile
	key_file = "${var.key_path}"
	}
	instance_type = "m1.small"
	# Lookup the correct AMI based on the region
	# we specified
	ami = "${lookup(var.aws_amis, var.aws_region)}"
	# The name of our SSH keypair you've created and downloaded
	# from the AWS console.
	#
	# https://console.aws.amazon.com/ec2/v2/home?region=us-west-2#KeyPairs:
	#
	key_name = "${var.key_name}"
	# Our Security group to allow HTTP and SSH access
	security_groups = ["${aws_security_group.default.name}"]
	# We run a remote provisioner on the instance after creating it.
	# In this case, we just install nginx and start it. By default,
	# this should be on port 80
	provisioner "remote-exec" {
	inline = [
	"sudo apt-get -y update",
	"sudo apt-get -y install nginx",
	"sudo service nginx start"
	]
	}
	}

view raw main.tf hosted with ❤ by GitHub

outputs.tf

	output "address" {
	value = "${aws_elb.web.dns_name}"
	}

view raw outputs.tf hosted with ❤ by GitHub

variables.tf

	variable "key_name" {
	description = "Name of the SSH keypair to use in AWS."
	}
	variable "key_path" {
	description = "Path to the private portion of the SSH key specified."
	}
	variable "aws_region" {
	description = "AWS region to launch servers."
	default = "us-west-2"
	}
	# Ubuntu Precise 12.04 LTS (x64)
	variable "aws_amis" {
	default = {
	eu-west-1 = "ami-b1cf19c6"
	us-east-1 = "ami-de7ab6b6"
	us-west-1 = "ami-3f75767a"
	us-west-2 = "ami-21f78e11"
	}
	}

view raw variables.tf hosted with ❤ by GitHub

Cheers,
Diego Pacheco