Hi All.
Docker have an "official" build repository of images (
hub.docker.com sometimes features them). These are the images you can get by running "docker pull redis" - ie global namespace. The idea being that they are a neat place to start - for people either new to docker or new to the tool they want to run.
As of today there is version of jenkins in this docker repository which is a vanilla ubuntu (14.04) running jenkins LTS.
This also includes some basic dev tooling on the assumption that people will want to run builds inside the container (as well as slaves - it can do slaves as the slave jnlp port is fixed - necessary for docker to forward the port - it can't be dynamically assigned - hence the init.groovy - that is all it does).
docker run -p 8080:8080 jenkins - is the minimal needed to run it (and you will have LTS jenkins)
LTS was picked as the process for updates to the official repositories is not compatible with a high frequency releases (basically a PR has to be issued and reviewed to the "stackbrew" system) - but LTS is perfect.
I would like to look at doing a very similar image for weekly releases that is published to the jenkinsci hub group - this would be published with each release, but based on pretty much the same image but non LTS.
Happy to discuss more, Nicolas suggested we could shift to Oracle JDK (as that is more common) - currently it is JDK, and perhaps should not bundle maven with it and so on (I do like using OS packages where possible as it makes it easy for the user to upgrade locally in place - it is perfectly reasonable to have a Dockerfile that says "FROM jenkins" and add your own deps, update and so on).
Please do fork and send pull requests, this is not immutable and generally easy to change - only a PR is needed to update it.