This document discusses continuous integration practices used by various companies including KuberDock, OpenStack, Spotify, and Ancestry. It describes how OpenStack uses Zuul for its CI/CD pipeline involving over 800 projects and 2,500 contributors. Spotify uses Helios for seamless monthly desktop client releases across 12,000 servers and 100 million users. KuberDock currently uses Vagrant and Ansible for automated dev environments but plans to scale testing through parallel pipelines and make CI services central to its release and testing processes.