Vitess is a storage platform for scaling MySQL. It is optimized to run as effectively in cloud architectures as it does on dedicated hardware. It combines many important features of MySQL with the scalability of a NoSQL database.
It's been actively developed since 2011, and is currently used as a fundamental component of YouTube's MySQL infrastructure, serving thousands of QPS per server. If you want to find out whether Vitess is a good fit for your project, please visit vitess.io.
There are a couple of videos from sougou that you can watch: a short intro prepared for Google I/O 2014 and a more detailed presentation from @Scale '14.
Unless otherwise noted, the vitess source files are distributed under the BSD-style license found in the LICENSE file.