IaC (Infrastructure as Code) Step by Step

This repository contains examples used in practical labs related to cloud technologies taught at DCSE / UWB

Prerequisites

• An IDE like Visual Studio Code with plugins for and Ansible
• Terraform (HashiCorp) installed
• Ansible installed
• Access to a OpenNebula account

Installing Terraform

Just follow the instructions provided at HashiCorp Learn Website in order to install the Terraform CLI.

Installing Ansible

Because Ansible is developed in the Python language, you will need to install it first if you haven't yet. Then you can install Ansible using pip as described in the Ansible Installation Guide

Setting up OpenNebula as a Terraform provider

We will setup an OpenNebula client as a Terraform provider in the following three steps:

1. Install OpenNebula Tools
2. Generate an OpenNebula password token and setup the OpenNebula client
3. Define OpenNebula as a provider in the HCL (HashiCorp Configuration Language)

1. Installing the OpenNebula Tools

In this short installation guide we will focus only on Ubuntu Linux (which should cover a major set of Linux distros including WSL2). Before you start with the installation, you have to determine you OS release. One of the following 3 methods should work for you:

lsb_release -a

cat /etc/issue

cat /etc/os-release

Next, it's good to know your OpenNebula frontend version. It's not necessary, but can help to avoid problems with incompatible versions. Login into your local/hosted OpenNebula frontend and look at the navigation menu:

Now you know the versions of both OS release and OpenNebula frontend, so you can access the appropriate repository, for example:

https://downloads.opennebula.io/repo/6.3.90/Ubuntu/20.04/

or, more suitable for the provided examples:

https://downloads.opennebula.io/repo/5.12.0.4/Ubuntu/20.04/

For all available versions, look at https://downloads.opennebula.io/repo/

Finally, install the OpenNebula Tools by entering these commands:

wget -q -O- https://downloads.opennebula.org/repo/repo.key | apt-key add -
echo "deb https://downloads.opennebula.org/repo/5.12.0.4/Ubuntu/20.04 stable opennebula" > /etc/apt/sources.list.d/opennebula.list
apt-get update
apt-get install opennebula-tools

2. Generate an OpenNebula password token and prepare it for use with OpenNebula CLI Tools

Login into the OpenNebula frontend and generate a login token:

Copy the generated token to the file .one/one_auth in your home directory:

mkdir "$HOME/.one"
echo 'your-username:your-login-token-6f41e9a367b9660etc...' > "$HOME/.one/one_auth"

You will be probably using the same frontend the whole time, so you can make your life easier by setting the following environment variable in your ~/.bashrc holding the URL of the default server used by the CLI tools:

export ONE_XMLRPC="https://your-opennebula-server/RPC2"

Check if your setting work with:

oneimage list
onevm list

3. Defining OpenNebula as a provider in Terraform

At the start of your HCL (HashiCorp Configuration Language) file describing the infrastructure components/resources add the following code snippet:

terraform {
  required_providers {
    opennebula = {
      source = "OpenNebula/opennebula"
      version = "0.4.3"
    }
  }
}

provider "opennebula" {
  endpoint      = "https://your-opennebula-server/RPC2"
  username      = "your-username"
  password      = "your-login-token-6f41e9a367b9660etc..."
}

Of course, replace the provided endpoint, username and password values with real ones or use pre-defined variables.

Provided examples

• Step 01 - very basic initial example (HCL)
• Step 02 - remote-exec script provisioner (HCL)
• Step 03 - create similar VMs (HCL)

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