Since there is a new reply on this quite old thread, I figured I’d update it with where we are now. For our new projects, I’ve actually taken us off Jenkins and tried to simply things using Gitlab for the entire pipeline. It’s actually working pretty well. Gitlab is takes docker into account at almost every step of the way. We have Gitlab in Rancher using gitlab-runner containers building images themselves. There are definitely hurdles (one of which is getting the runner-spawned containers onto the rancher managed network), but int he end we have fairly small and simple docker/rancher compose files and gitlab-ci.yml files running pretty large scale builds.
As always, I’m looking to simplify, simplify, simplify…