Vagrant providers each require a custom provider-specific box format.
This folder shows the example contents of a box for the ovirt3 provider.
To turn this into a box:
$ tar cvzf dummy.box ./metadata.json ./Vagrantfile
This box works by using Vagrant's built-in Vagrantfile merging to setup defaults for oVirt. These defaults can easily be overwritten by higher-level Vagrantfiles (such as project root Vagrantfiles).