libswarm

A minimalist toolkit to compose network services. An interesting intro is available at http://www.tech-d.net/2014/07/03/libswarm/

Using that guide, you can, for example, run something like:

$ swarmd 'dockerserver tcp://localhost:2376' 'dockerclient tcp://localhost:2375'
copying task output from &libswarm.receiverWrapper{Receiver:(*libchan.PipeReceiver)(0xc210000508)} to &libswarm.senderWrapper{Sender:(*libchan.PipeSender)(0xc210000650)}
Starting Docker server...

This will start a Rest API server at localhost:2376 that delegates the execution to a running docker engine at localhost:2375

In fact, a subsequent call like the following:

sudo docker -H tcp://localhost:2376 ps

will produce the usual list of containers and the following log line:

Calling GET /containers/json

Limitations

Currently, swarmd allows you to aggregate multiple docker engines, but the containers created on the aggregated swarmd service will not be able to ping each other, in other words, they won't see each other.

Docker community is working on a new links implementation that should help with it