Start docker daemon via plugin if it have not alread run

[nikita-sheremet-java-developer]

Hello,

Pushing and pulling docker images to and from docker registries can be quite slow, even when everything is running on your laptop. So its useful to avoid that step when working locally as it speeds up your edit -> compile -> run cycle time and helps you develop faster.

So if you are running Kubernetes locally on your laptop such as via the Fabric8 vagrant image its a good idea to use the same docker daemon that is running inside vagrant on your host operating system (OS X / Windows) when using the docker command and building images.

The idea is good but what if it is needed to build docker image and upload it repository during building cycle? I mean that there are 2 situations with building images:

1. when developer build image for testing and debugging <- here using/reusing local running daemon is good idea
2. when CI (or a developer) builds docker image via maven and uploads it to repository <- why not run standart `docker build -t command here?

I am now trying to use your plugin and bit confused why you plugin does not have possibility to just run docker daemon before build? (E.g. I got No <dockerHost> given error when I able to run docker build -t myRepoUrl) Possibility to run docker by plugin illiminates additional actions from me as developer e.g. I just run a plugin and do not care aboout any docker daemon running config. Or plugin may have a config and checks whether docker daemon is running and if it is not - run new one.

Could you please add such functionality to your plugin?