docker-machine on z Systems

Recent posts have shown how to get compose, swarm, and the registry working. Of the prominent docker tools, the last one missing is docker-machine. machine is a tool that turns a Linux server into a Docker host. It can even create the server in the first place, e.g. in various public Cloud environments or through OpenStack. https://docs.docker.com/machine/ is the starting point of the documentation.

Let's see how docker-machine can be adapted for Linux on z Systems. Caution: long post.
We will use the generic driver which uses an existing Linux image as starting point, and uses its ssh access to make it a Docker host. First step -- let's setup the build environment for machine.