Vagrant 1.6 changed the order of steps Vagrant performs on initialization: it now evaluates the project's Vagrantfile after loading plugins and parsing command-line arguments. This means that the various subcommands provide for role management no longer work, since the relevant plugins are loaded from the top of Vagrantfile, which is now too late a stage to be loading plugins.
Loading plugins from Vagrantfile was always a bit of a hack, but it was a good hack that allowed us to bridge over a complicated plugin packaging process and provide a tailored Vagrant experience right from 'vagrant up'.
I'd like to fix this without adding steps to the installation process, but I'm not sure how. I spent a few hours bashing my head against this problem earlier today and didn't get anywhere. I would really welcome a creative solution.
The relevant bug is https://bugzilla.wikimedia.org/show_bug.cgi?id=65066 , originally reported by Robert Vogel.
Ori