Introducing Vagrant

Have you ever heard the following? "Welcome to the team! Here's a list of 15 applications to install, the instructions are in the team room, somewhere. See you in a week!" Or: "What do you mean it broke production, it runs fine on my machine?" Or: "Why is this working on her machine and his machine, but not my machine?"

Development environments are becoming more complex, with more moving parts and tricky dependencies. Virtualization has been a huge boon for the IT industry in saving costs, increasing flexibility and maintaining control over complex environments. Rather than focusing on virtualization on the delivery side, let's look at how you can provide that flexibility and control to developers to manage multiple development environments easily using Vagrant.

What Is Vagrant?

Vagrant is an open-source (MIT) tool for building and managing virtualized development environments developed by Mitchell Hashimoto and John Bender. Vagrant manages virtual machines hosted in Oracle VirtualBox, a full x86 virtualizer that is also open source (GPLv2).

A virtual machine is a software implementation of a computer, running a complete operating system stack on a virtualizer. It is a full implementation of a computer with a virtual disk, memory and CPU. The machine running the virtualizer is the Host system. The virtual machine running on the virtualizer is the Guest system. As far as the Guest operating system is concerned, it is running on real hardware. From the perspective of the Host, all of the Guest's resources are used by the virtualizer program. A Box, or base image, is the prepackaged virtual machine that Vagrant will manage.

Installing Vagrant

Starting in version 1.0, Vagrant provides two installation methods: packaged installers for supported platforms or a universal install with Ruby Gems. This article covers installation using Gems. This method has three parts: 1) install VirtualBox, 2) install Ruby and 3) install Vagrant itself.

VirtualBox is available from the VirtualBox home page with builds for Windows, OS X, Linux and Solaris. Note that Oracle provides the Oracle VM VirtualBox Extension Pack on the Download site that provides additional features to the virtualizer. The Extension Pack has a separate license (Personal Use and Evaluation License) and is not needed to use Vagrant, but if the Box you are using was created using the Extension Pack, you will need to install the Extension Pack as well.

Ruby is a popular dynamically typed object-oriented scripting language. Ruby is available out of the box in OS X, and most Linux distributions also have a Ruby package available. For Windows users, the RubyInstaller Project provides an easy way to install the Ruby runtime.

Ruby libraries and applications are available in packages called RubyGems or Gems. Ruby comes with a package management tool called gem. To install Vagrant, run the gem command:

> gem install vagrant

Vagrant is a command-line tool. Calling vagrant without additional arguments will provide the list of available arguments. I'll visit most of these commands within this article, but here's a quick overview:

• init — create the base configuration file.

• up — start a new instance of the virtual machine.

• suspend — suspend the running guest.

• halt — stop the running guest, similar to hitting the power button on a real machine.

• resume — restart the suspended guest.

• reload — reboot the guest.

• status — determine the status of vagrant for the current Vagrantfile.

• provision — run the provisioning commands.

• destroy — remove the current instance of the guest, delete the virtual disk and associated files.

• box — the set of commands used to add, list, remove or repackage box files.

• package — used for the creation of new box files.

• ssh — ssh to a running guest.

The last thing you need to do in your installation is set up a base image. A Box, or base image, is the prepackaged virtual machine that Vagrant will manage. Use the box command to add the Box to your environment. The vagrant box add command takes two arguments, the name you use to refer to the Box and the location of the Box:

> vagrant box add lucid32 http://files.vagrantup.com/lucid32.box

This command adds a new Box to the system called "lucid32" from a remotely hosted site over HTTP. Vagrant also will allow you to install a Box from the local filesystem:

> vagrant box add rhel5.7 rhel5.7-20120120-1223.box
[vagrant] Downloading with Vagrant::Downloaders::File...
[vagrant] Copying box to temporary location...
[vagrant] Extracting box...
[vagrant] Verifying box...
[vagrant] Cleaning up downloaded box...
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