PolicyKit pkexec – Running without Prompting for Authentication

The following guide explains how to configure a pkexec command to run without prompting for authentication.  This is helpful when you want to grant root access to key piece of the system (such as allowing virsh commands from another user when running KVM virtual machines) or just want to run a GUI command as root without having to login or use authentication. 

https://askubuntu.com/questions/383747/how-to-configure-pkexec-to-not-ask-for-password#answer-388660

Or in our own archive in case the above link disappears.