I recently launched a Meteor based application that runs in a Docker container on a server running coreOS. I have a container running the node application, and a container running MongoDB. (Find an example of my Dockerfile for Meteor apps here).
When I first launched the application, I needed to copy up a bunch of mongo collections to the mongo container that I had running. It took me a minute to figure out how to do it, so I thought I'd share it: