Zuul CI is an open source CI/CD that powers some of the largest Open Source development efforts. It is written in Python and is usually used to gate git servers including Gerrit and GitHub.
Zuul CI is a program that drives continuous integration, delivery, and deployment systems with a focus on project gating and interrelated projects.
Project documentation can be found at https://zuul-ci.org/docs/zuul/ and its community is active on #zuul
channel on freenode irc.