[thwest]

My current workflow is similarly VM oriented and I've just started playing with docker, so an experienced user can feel free to chime in.

Docker is more about process isolation using LXC than having a whole VM for a particular app. You still need some operating system underneath your docker deploys, so it feels redundant in a world where I already have a VM for each project. However I could see it shining at hosting a half dozen to few dozen services from the same machine.

One thing I don't like aesthetically is the tendency to expose local folders to the container. I prefer complete encapsulation.

[mdaniel]

Docker doesn't expose local folders to the container unless you specifically and verbosely instruct it to do so. Unless you're thinking of the ADD and COPY instructions, which are entirely optional (or you can, IIRC, use ADD with a URL).

If you are referring to docker-machine (née boot2docker) sharing your home directory into the VirtualBox, that's a necessity brought on by the fact that you are not developing on Linux and Docker is (currently) Linux only, so something has to give in that relationship. It is, IIRC, also more-or-less optional, with the tremendous downside that you must scp/rsync your workspace into VirtualBox by hand, before ssh-ing in to execute `docker build`.