Wikipedia
Goobuntu is a Linux distribution, based on the 'long term support'-versions of Ubuntu, that is internally used by almost 10,000 of Google's employees. It adds a number of packages for in-house use, including security features and disables the installation of some applications, but is otherwise similar. Thomas Bushnell, the Google manager for the company's Linux desktops, displayed Goobuntu at LinuxCon 2012. Bushnell explained that "Goobuntu is simply a light skin over standard Ubuntu."
Some have suggested that Google might plan to market the distribution more widely. While both Google and Mark Shuttleworth, who spearheaded the development of Ubuntu, have confirmed that Goobuntu exists and is used internally, both have strongly denied suggestions that Google has any plans to market the operating system.
Mark Shuttleworth has confirmed that Google contributes patches to Ubuntu.
Google uses Puppet to manage its installed base of Goobuntu machines.