How to create a new container from the difference from VM and stock Ubuntu 14.04 LTS

Newb here. I have a working VM of my entire product that runs on Ubuntu 14.04 LTS that has been tweaked and honed over a year. I would like to create a container that has all the deltas from this VM and a stock Ubuntu 14.04 LTS install without starting over from scratch since I’m not entirely sure all that has changed. Is there a document or tool to explain how to do this? It seems like it would be a desirable use case.

This approach is somewhat antithetical to the docker approach.

What you’re describing would prolong the issue of not being sure what has been done to the state of the system. Docker’s approach is about containers that are treated like cattle, not pets. The are ephemeral in nature, and state is stored outside the containers themselves.

I don’t know how you’d generate a delta of your system from what it was a long time ago, but you could potentially take a tarball dump of the filesystem as it is now and import that as its own image.

It would probably be a much better approach in the long run to identify the different services that this machine runs and break them out into their own containers one at a time.