You can control Ardour over MIDI: roll and stop transport, arm for recording, change gain/pan in tracks and busses, and do other things. Ardour ships with 50+ MIDI maps, mostly for some of the MIDI keyboards by AKAI, M-Audio, Novation, and Arturia. If there is no ready-to-use MIDI map for your particular device yet, you can create your own. Here is how you do that

Ardour ships with 50+ ready-to-use MIDI maps. So if you have a supported device, you can control basic things like transport in the program from a MIDI keyboard, and it works very nearly out of the box. Here's how you can do it