OctoPrint is a server controlling a 3D-printer over web-interface, running on the small computer like Raspberry Pi or PCDuino with Linux OS. This article describes how to setup OctoPrint on Raspberry Pi 2 with Ubuntu OS. Read another article to setup OctoPrint on PCDuino.
Raspberry Pi 2 has ARMv7-based CPU on-board – this allows to run Ubuntu directly on this small computer. Ubuntu has plenty of features in compare to special editions of Linux distributives for such small devices and therefore less limitations with installing specific programs and components on it.