Since the Parallels provider is a Vagrant plugin, installing it is easy:
$ vagrant plugin install vagrant-parallels
The Vagrant plugin installer will automatically download and install
- Vagrant v1.8 or higher (there are known issues with Vagrant v1.9.5 [GH-297] and v1.9.6 [GH-301])
- Parallels Desktop for Mac version 10 or higher
Only Pro and Business editions of Parallels Desktop for Mac can be used with this Vagrant provider.