Vagrant providers each require a custom provider-specific box format. This folder shows the example contents of a box for the openstack provider. To turn this into a box:

$ tar cvzf openstack.box ./metadata.json ./Vagrantfile

This box works by using Vagrant's built-in Vagrantfile merging to setup defaults for Openstack. These defaults can easily be overwritten by higher-level Vagrantfiles (such as project root Vagrantfiles).