Vagrant is a handy and easy-to-use Virtual Machine tool that can be used within your command-line interface. In a nutshell, it makes it easy to create and configure lightweight, reproducible developer environments.

In this mini course, you will learn all about virtualization. You will learn how to set up a Vagrant environment, build your own VM, as well as Vagrant commands which you can use from the command line.

In the latter half of the course, you will learn how to work with vagrantfile, networking, and data sharing. In all, this is your crash course for understanding the fundamentals of Vagrant.

A Guide to Vagrant and Virtual Machines

So far, we've just spun up our Vagrant VM.

Now, let’s get our hands dirty with Vagrantfile.

# `Vagrantfile`

`Vagrantfile` is a configuration file that Vagrant creates during the `vagrant init <box name>` process. This file consists of the configuration for your `VM`. This configuration file is defined completely in the Ruby language. Don’t worry if you don’t know the Ruby language, as it is quite easy to use.  When we run the `vagrant up` command, Vagrant locates this config file in the current directory and loads the guest machine using the configuration defined in the file.

We can do a lot more than run a default configured VM. Let’s look at some of our options.


## Customizing `Vagrantfile`

Now, let's spin up our Vagrant VM again, but this time, with a new image and in minimal mode.

When we first built our VM, we ran the command: `vagrant init ubuntu/xenial64`. By running this command, we successfully generated our `Vagrantfile`. But, in that config file, there are a lot of comments, and it’s quite long, isn’t it?  Just forget about those long comments for now! We'll build something cleaner. 

You remember boxes, right? We'll add a box first, and, then we'll do `init` in `--minimal` mode.

## Adding a box

Make sure you’re in the Vagrant directory that we created earlier. Then, run the command below.
```
$ vagrant box add centos/7
```
This time, we're running a centos image - A Redhat Distro.

**Run Cleaner Mode**

Run the following command to initialize the `Vagrantfile` in minimal mode. 
```
$ vagrant init --minimal
```

Now, if you open up your `Vagrantfile`, it'll look something like this.
```
Vagrant.configure("2") do |config|
  config.vm.box = "base"
  config.vm.provider "virtualbox" do |vb|
    vb.memory = "1024"
    vb.cpus = "2"
  end
end
```
Note, the `config.vm.box` is set to  `"base"`, i.e., we’re working with a `“base”` box.
We need to change this. Let's add the box that we've created in the previous step.

```
Vagrant.configure("2") do |config|
  config.vm.box = "centos/7"
  config.vm.provider "virtualbox" do |vb|
    vb.memory = "1024"
    vb.cpus = "2"
  end
end
```

Now this config file tells us that it is running the Vagrant configuration version, `configure("2")`, and the box or image we're using is `config.vm.box = "centos/7"`.

## Providers
Let's learn about the code that I've added below.
```
config.vm.provider "virtualbox" do |vb|
    vb.memory = "1024"
    vb.cpus = "2"
  end
```

Vagrant needs providers to run their VMs. In our case, we’re using `VirtualBox`, so we have to define our provider configuration using the `config.vm.provider` method. Without this block of code, Vagrant won’t be able to boot up our Virtual Machine.

Explore more about providers here: [Providers](https://www.vagrantup.com/docs/providers/).

The information discussed so far is sufficient enough for you to tell what’s really going on in the config file.

## Updating `Vagrantfile`
To update the `Vagrantfile`, just replace `base` with the box name from the previous step.

```
Vagrant.configure("2") do |config|
  config.vm.box = "centos/7"
end
```
Now, let’s declare a `hostname` for our Virtual Machine.

A `hostname` is a unique name for a computer or network node in a network. Hostnames are specific names, or character strings, that refer to a host and make it usable for the network and users.

```
Vagrant.configure("2") do |config|
  config.vm.box = "centos/7"
  config.vm.hostname = "server.example.com"
  config.vm.provider "virtualbox" do |vb|
    vb.memory = "1024"
    vb.cpus = "2"
  end
end
```

Now, let’s learn about networking.


In this lesson, we'll learn more about Vagrantfile and dive deeper into its configurations.

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Working with Vagrantfile

`Vagrantfile`

Customizing `Vagrantfile`

Working with Vagrantfile

Vagrantfile

Customizing Vagrantfile

`Vagrantfile`

Customizing `Vagrantfile`