To debug WebPagetest Private Instance at local.
ansible is required on your Mac.
$ brew install ansible
$ git clone https://github.com/WPO-Foundation/webpagetest.git
$ git clone https://github.com/1000ch/webpagetest-local.git
$ vagrant up --provision
See Fixing 'vagrant up' Errors.
$ sudo /Library/StartupItems/VirtualBox/VirtualBox restart
MIT.