Access an application running in a Docker Container which is running inside an emulated CoreOS in Ubuntu

问题

My problem is: I am running an application called Cloud9 inside a container, this application runs at default on localhost:3131, but it is changeable. This Docker Container is running on a CoreOS VM, and the CoreOS VM is running on Ubuntu 14.04 through VirtualBox.

What I need is: from the browser on Ubuntu be able to access the Cloud9 application running inside Docker.

I have tried several things to work on the Docker Network (Pipeworks, Docker0 settings, VirtualBox settings, etc), but I am completely stuck,

How could I access the application through all this layers: Ubuntu > CoreOS > Docker > Cloud9 ?

Thanks a lot.

来源：https://stackoverflow.com/questions/24371508/access-an-application-running-in-a-docker-container-which-is-running-inside-an-e