I created a docker image to run a MongoDB sharded cluster in one container. It's hosted on Docker Hub:
You can run it like the original
$ docker run --rm --publish 27017:27017 a2ikm/sharded-mongo
It should be useful if you run an application on a sharded cluster and also want to run its CI on the same coodination.
Actually, I've introduced it to the CI of mongo_mapper gem. It helps me test it against compatibility changes of MongoDB which affects only a sharded cluster.
If you are interested, please take a look it 😄