I recently wrote an article featured on my employer’s website. It’s a very introductory and educationally focused article on creating a custom Plone 5 buildout, configuring a Docker image with it, and deploying the image to DC/OS.
You can find the article at www.wildcardcorp.com/blog/creating-a-custom-plone-5-docker-image-and-deploying-it-to-dc-os
If you want to skip over the fluff of the article, I tried to incorporate a lot into the comments of the configuration files involved. Those can be found on my employer’s GitHub organiztaion in the plone.docker.custom repository.