I will introduce a library for distributed execution your spec files. This library has two strategies in order to distribute spec files. One divides spec files into some groups and distributes them. The other distributes every code example following the producer-consumer way.I will also describe the usage of the library in COOKPAD. COOKPAD develops large Rails applications including about 800 models. I will demonstrate the effectiveness of the library by showing the time saved by a COOKPAD CI job by using this library.