Terraform

Terraform is an application by HashiCorp that is designed to treat infrastructure as code. Lately, I have been working with it to begin automation of resources within AWS, and have been quite pleased.

Lets get started with building out a Windows 2012 R2 server with Terraform on AWS.

You are going to need to have the following items configured in AWS in order for this to work, as I am not going to be using Terraform to build out these items.

Since the purpose of this test is not to create a VPC, subnets, security_groups, etc, all of those will need to be created beforehand. You will then need the identifiers from these later, for use in building out the server. I always recommend building out your VPC in its own stack, and never mixing it with others. It is a vital piece of the infrastructure that should be touched as little as possible.

Items Needed for this Demo:

• IAM Instance Role
• VPC Security Group ID
• Subnet ID
• Key to use for Instance Creation

For this example you are going to need just two files. These files are the variables.tf and main.tf. Technically, you can name them any good old name you want, as long as they end in .tf. I almost think it is more confusing to go with main.tf and variables.tf. As such, I am going to go ahead and change the name of the files. I use Atom for editing my files, and so descriptive filenames are nice.

mkdir stand_alone_windows_2012
cd stand_alone_windows_2012
touch win2012_test_instance.tf
touch win2012_test_variables.tf

Now let us add the file that we are going to need for the variables. (I will admit that there are some values hard coded into the second file, but that is because I have been testing this to get it working.

variable "admin_password" {
  description = "Windows Administrator password to login as."
}

variable "aws_region" {
  description = "AWS region to launch servers."
  default = "us-west-2"
}

# Windows Server 2012 R2 Base
variable "aws_amis" {
  default = {
    us-east-1 = "ami-3f0c4628"
    us-west-2 = "ami-b871aad8"
  }
}

variable "key_name" {
  description = "Name of the SSH keypair to use in AWS."
  default = {
    "us-east-1" = "AWS Keypair"
    "us-west-2" = "AWS Keypair"
  }
}

variable "aws_instance_type" {
  default = "m4.large"
}

variable "aws_subnet_id" {
  default = {
    "us-east-1" = "subnet-xxxxxxxx"
    "us-west-2" = "subnet-xxxxxxxx"
  }
}

variable "aws_security_group" {
  default = {
    "us-east-1" = "sg-xxxxxxxx"
    "us-west-2" = "sg-xxxxxxxx"
  }
}

variable "node_name" {
  default = "not_used"
}

You will need to go through this file, and update the variables as needed, and create any resources that you do not happen to have. This would include subnets and vpc based security groups.

The next file is win2012_test_instance.tf. This is what does all the heavy lifting. In my example, I am also installing chef, but that is because I plan on automating my entire infrastructure, not just server creation.

# Specify the provider and access details
provider "aws" {
  region = "${var.aws_region}"
}

data "template_file" "init" {
    /*template = "${file("user_data")}"*/
    template = <<EOF
<script>
  winrm quickconfig -q & winrm set winrm/config/winrs @{MaxMemoryPerShellMB="300"} & winrm set winrm/config @{MaxTimeoutms="1800000"} & winrm set winrm/config/service @{AllowUnencrypted="true"} & winrm set winrm/config/service/auth @{Basic="true"}
</script>
<powershell>
  netsh advfirewall firewall add rule name="WinRM in" protocol=TCP dir=in profile=any localport=5985 remoteip=any localip=any action=allow
  $admin = [ADSI]("WinNT://./administrator, user")
  $admin.SetPassword("${var.admin_password}")
  iwr -useb https://omnitruck.chef.io/install.ps1 | iex; install -project chefdk -channel stable -version 0.16.28
</powershell>
EOF

    vars {
      admin_password = "${var.admin_password}"
    }
}

resource "aws_instance" "win2012_instance" {
  connection {
    type = "winrm"
    user = "Administrator"
    password = "${var.admin_password}"
  }
  instance_type = "${var.aws_instance_type}"
  ami = "${lookup(var.aws_amis, var.aws_region)}"
  key_name = "${var.key_name}"
  tags {
    Name = "MY_DYNAMIC_STATIC_NAME",
    Env = "TEST"
  }
  key_name = "${lookup(var.key_name, var.aws_region)}"
  iam_instance_profile = "STATIC_ROLE_NAME_SHOULD_BE_A_VARIABLE"
  tenancy = "dedicated"
  subnet_id = "${lookup(var.aws_subnet_id, var.aws_region)}"
  vpc_security_group_ids = ["${lookup(var.aws_security_group, var.aws_region)}"]
  /*user_data = "${file("user_data")}"*/
  user_data = "${data.template_file.init.rendered}"
}