Run specific Chef roles with --flag?

[Jon Baer]

Hi,

Is it possible to instead of placing all the Chef role material into a Vagrant file to be able to add roles by command line @ run time?

http://docs.vagrantup.com/v2/provisioning/chef_solo.html

I would like to do both as the following:  vagrant --provider aws --role web, vagrant --provider digitalocean --role db, etc, etc, etc.

Thanks.

- Jon