Shipyard: Container Attaching

One of the great features of Docker is the ability to run interactive containers. You can attach to a container which connects you to a terminal. From there it is just like any other virtual machine or instance. I have wanted something like this in Shipyard since I started it, but it was on the back burner. Until a few days ago.

ukd1 had mentioned in #docker that they were building a web based terminal utilizing websockets to attach to containers from the browser. ukd1 and their team worked on it that afternoon and by the evening there was a pull request for Shipyard.

In order for it to work, Docker needs websocket support in the api. There is a pull request open but has not been merged as of this writing. To get it working however, is rather simple:

Clone the latest Docker and checkout the latest stable tag (currently v0.4.8):


git clone

git checkout v0.4.8

Add the upstream from the pull request [dotcloud/docker#1146](

git remote add ws

Create a websocket branch (optional):

git checkout -b websockets

Merge code from pull request:

git pull ws feature/attach_ws

Build new Docker binary:


Now you can run bin/docker and use Shipyard to access the console via websockets.

The console support is still in branch (terminal) in the Shipyard repository until the 1146 pull request gets merged and released as stable in Docker.

Here is a quick screencast showing the feature:

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