Riot builds a lot of software. At the start of 2015 we were looking at 3000 build jobs over a hundred different applications and dozens of teams. We were handling nearly 750 jobs per hour and our build infrastructure needed to grow rapidly to meet demand. We needed to give teams total control of the “stack” used to build their applications and we needed a solution that enabled agile delivery to our players. On top of that, we needed a scalable system that would allow a team of four engineers to support over 250. After as few explorations, we built an integrated Docker solution using Jenkins that accepts docker images submitted as build environments by engineers around the company . Our “containerized” farm now creates over 10,000 containers a week and handles nearly 1000 jobs at a rate of about 100 jobs an hour. In this occasionally technical talk, we’ll explore the decisions that led Riot to consider Docker, the evolutionary stages of our build infrastructure, and how the open source and in-house software we combined to achieve our goals at scale. You’ll come away with some best practices, plenty of lessons learned, and insight into some of the more unique aspects of our system (like automated testing of submitted build environments, or testing node.js apps in containers with Chromium and xvfb).