git rebase is a very useful construct in source control management, as it allows you to re-apply your changes atop a different branch of the same repository. While this concept transitions perfectly to container management (updating a container could be as easy as a docker rebase), and the Docker client is inspired by the git semantics, Docker has no such feature (in fact, Solomon Hykes used rebase and merge as examples of things "that we don't want"). Currently, zypper-docker works by applying an updated layer on top of an existing image. While this does work quite well, it separates the process of updating the base image and updating all of your derivative images (you need to re-download new packages for each derivative image).

Currently, dealing with forkbombs and similar issues with Docker and runC is not very nice (you have to set a global limit for all Docker processes or you have to limit kernel memory which isn't very practical). I'm going to work on getting [some][1] [patches][2] merged into runC and Docker to enable PIDs support for Docker.

In many cases, people want to start containers on a system where the administrator is not happy about granting privileges to users or installing any new software. For example, when I was a researcher and wanted to run Python 3 on a computing cluster it was not possible to get the administrator to install Docker or Python 3.