An excerpt from http://www.sitepoint.com/re-introducing-vagrant-right-way-start-php/, by @swader
I often get asked to recommend beginner resources for people new to PHP. And, it’s true, we don’t have many truly newbie friendly ones. I’d like to change that by first talking about the basics of environment configuration. In this post, you’ll learn about the very first thing you should do before starting to work with PHP (or any other language, for that matter).
We’ll be re-introducing Vagrant powered development.
Please take the time to read through the entire article – I realize it’s a wall of text, but it’s an important wall of text. By following the advice within, you’ll be doing not only yourself one hell of a favor, but you’ll be benefitting countless other developers in the future as well. The post will be mainly theory, but in the end we’ll link to a quick 5-minute tutorial designed to get you up and running with Vagrant in almost no time. It’s recommended you absorb the theory behind it before you do that, though.
Just in case you’d like to rush ahead and get something tangible up and running before getting into theory, here’s the link to that tutorial.
What?
Let’s start with the obvious question – what is Vagrant? To explain this, we need to explain the following 3 terms first:
- Virtual Machine
- VirtualBox
- Provisioning
Virtual Machine
In definitions as simple as I can conjure them, a Virtual Machine (VM) is an isolated part of your main computer which thinks it’s a computer on its own. For example, if you have a CPU with 4 cores, 12 GB of RAM and 500 GB of hard drive space, you could turn 1 core, 4 GB or RAM and 20GB or hard drive space into a VM. That VM then thinks it’s a computer with that many resources, and is completely unaware of its “parent” system – it thinks it’s a computer in its own right. That allows you to have a “computer within a computer” (yes, even a new “monitor”, which is essentially a window inside a window – see image below):
A Windows VM inside a Mac OS X system
This has several advantages:
- you can mess up anything you want, and nothing breaks on your main
machine. Imagine accidentally downloading a virus – on your main
machine, that could be catastrophic. Your entire computer would be at
risk. But if you downloaded a virus inside a VM, only the VM is at
risk because it has no real connection to the parent system it lives
off of. Thus, the VM, when infected, can simply be destroyed and
re-configured back into existence, clean as a whistle, no
consequences. - you can test out applications for other operating
systems. For example, you have an Apple computer, but you really want
that one specific Windows application that Apple doesn’t have. Just
power up a Windows VM, and run the application inside it (like in the
image above)! - you keep your main OS free of junk. By installing stuff
onto your virtual machine, you avoid having to install anything on
your main machine (the one on which the VM is running), keeping the
main OS clean, fast, and as close to its “brand new” state as
possible for a long time.
You might wonder – if I dedicate that much of my host computer to the VM (an entire CPU core, 4GB of RAM, etc), won’t that:
- make my main computer slower?
- make the VM slow, because that’s kind of a weak machine?
The answer to both is “yes” – but here’s why this isn’t a big deal. You only run the VM when you need it – when you don’t, you “power it down”, which is just like shutting down a physical computer. The resources (your CPU core, etc.) are then instantly freed up. The VM being slow is not a problem because it’s not meant to be a main machine – you have the host for that, your main computer. So the VM is there only for a specific purpose, and for that purpose, those resources are far more than enough. If you really need a VM more powerful than the host OS, then just give the VM more resources – like if you want to play a powerful game on your Windows machine and you’re on a Mac computer with 4 CPU cores, give the VM 3 cores and 70-80% of your RAM – the VM instantly becomes powerful enough to run your game!
But, how do you “make” a virtual machine? This is where software like VirtualBox comes in.
VirtualBox
VirtualBox is a program which lets you quickly and easily create virtual machines. An alternative to VirtualBox is VMware. You can (and should immediately) install VirtualBox here.
VirtualBox provides an easy to use graphical interface for configuring new virtual machines. It’ll let you select the number of CPU cores, disk space, and more. To use it, you need an existing image (an installation CD, for example) of the operating system you want running on the VM you’re building. For example, if you want a Windows VM as in the image above, you’ll need a Windows installation DVD handy. Same for the different flavors of Linux, OS X, and so on.
Provisioning
When a new VM is created, it’s bare-bones. It contains nothing but the installed operating system – no additional applications, no drivers, nothing. You still need to configure it as if it were a brand new computer you just bought. This takes a lot of time, and people came up with different ways around it. One such way is provisioning, or the act of using a pre-written script to install everything for you.
With a provisioning process, you only need to create a new VM and launch the provisioner (a provisioner is a special program that takes special instructions) and everything will be taken care of automatically for you. Some popular provisioners are: Ansible, Chef, Puppet, etc – each has a special syntax in the configuration “recipe” that you need to learn. But have no fear – this, too, can be skipped. Keep reading.
Vagrant
This is where we get to Vagrant. Vagrant is another program that combines the powers of a provisioner and VirtualBox to configure a VM for you.
You can (and should immediately) install Vagrant here.
Vagrant, however, takes a different approach to VMs. Where traditional VMs have a graphical user interface (GUI) with windows, folders and whatnot, thus taking a long time to boot up and become usable once configured, Vagrant-powered VMs don’t. Vagrant strips out the stuff you don’t need because it’s development oriented, meaning it helps with the creation of development friendly VMs.
Vagrant machines will have no graphical elements, no windows, no taskbars, nothing to use a mouse on. They are used exclusively through the terminal (or command line on Windows – but for the sake of simplicity, I’ll refer to it as the terminal from now on). This has several advantages over standard VMs:
- Vagrant VMs are brutally fast to boot up. It takes literally seconds to turn on a VM and start developing on it. Look how quickly it happens for me – 25 seconds flat from start to finish:
- Vagrant VMs are brutally fast to use – with no graphical elements to take up valuable CPU cycles and RAM, the VM is as fast as a regular computer
- Vagrant VMs resemble real servers. If you know how to use a Vagrant VM, you’re well on your way to being able to find your way around a real server, too.
- Vagrant VMs are very light due to their stripped out nature, so their configuration can typically be much weaker than that of regular, graphics-powered VMs. A single CPU core and 1GB of RAM is more than enough in the vast majority of use cases when developing with PHP. That means you can not only boot up a Vagrant VM on a very weak computer, you can also boot up several and still not have to worry about running out of resources.
- Perhaps most importantly, Vagrant VMs are destructible. If something goes wrong on your VM – you install something malicious, you remove something essential by accident, or any other calamity occurs, all you need to do to get back to the original state is run two commands: vagrant destroy which will destroy the VM and everything that was installed on it after the provisioning process (which happens right after booting up), and vagrant up which rebuilds it from scratch and re-runs the provisioning process afterwards, effectively turning back time to before you messed things up.
With Vagrant, you have a highly forgiving environment that can restore everything to its original state in minutes, saving you hours upon hours of debugging and reinstallation procedures.