Creating a Base Box
As with every provider, the VirtualBox provider has a custom box format that affects how base boxes are made.
Prior to reading this, you should read the general guide to creating base boxes. Actually, it would probably be most useful to keep this open in a separate tab as you may be referencing it frequently while creating a base box. That page contains important information about common software to install on the box.
Additionally, it is helpful to understand the basics of the box file format.
Advanced topic! This is a reasonably advanced topic that a beginning user of Vagrant doesn't need to understand. If you're just getting started with Vagrant, skip this and use an available box. If you're an experienced user of Vagrant and want to create your own custom boxes, this is for you.
In addition to the software that should be installed based on the general guide to creating base boxes, VirtualBox base boxes require some additional software.
VirtualBox Guest Additions
VirtualBox Guest Additions must be installed so that things such as shared folders can function. Installing guest additions also usually improves performance since the guest OS can make some optimizations by knowing it is running within VirtualBox.
Before installing the guest additions, you'll need the linux kernel headers and the basic developer tools. On Ubuntu, you can easily install these like so:
$ sudo apt-get install linux-headers-$(uname -r) build-essential
Next, make sure that the guest additions image is available by using the GUI and clicking on "Devices" followed by "Install Guest Additions". Then mount the CD-ROM to some location. On Ubuntu, this usually looks like this:
$ sudo mount /dev/cdrom /mnt/cdrom
Finally, run the shell script that matches your system to install the guest additions. For example, for Linux on x86, it is the following:
$ sudo sh /media/cdrom/VBoxLinuxAdditions.run
If you didn’t install a Desktop environment when you installed the operating system, as recommended to reduce size, the install of the VirtualBox additions should warn you about the lack of OpenGL or Window System Drivers, but you can safely ignore this.
If the command succeeds, then the guest additions are now installed!
Packaging the Box
Vagrant includes a simple way to package VirtualBox base boxes. Once you've installed all the software you want to install, you can run this command:
$ vagrant package --base my-virtual-machine
Where "my-virtual-machine" is replaced by the name of the virtual machine in VirtualBox to package as a base box.
It will take a few minutes, but after it is complete, a file "package.box" should be in your working directory which is the new base box. At this point, you've successfully created a base box!
This section documents the actual raw contents of the box file. This isn't as useful when creating a base box but can be useful in debugging issues if necessary.
A VirtualBox base box is an archive of the resulting files of exporting a VirtualBox virtual machine. Here is an example of what is contained in such a box:
$ tree . |-- Vagrantfile |-- box-disk1.vmdk |-- box.ovf |-- metadata.json 0 directories, 4 files
In addition to the files from exporting a VirtualBox VM, there is the "metadata.json" file used by Vagrant itself.
Also, there is a "Vagrantfile." This contains some configuration to properly set the MAC address of the NAT network device, since VirtualBox requires this to be correct in order to function properly.
When bringing up a VirtualBox backed machine, Vagrant imports the first "ovf" file found in the box contents.