Painless Docker - 2nd Edition

The Birth of the Moby Project: When Docker Outgrew Itself

When DotCloud launched Docker in March 2013, it was delivered as a single, tightly coupled project. The original goal was to provide one tool that could build, ship, and run containers through a unified workflow. As Docker adoption grew, this all-in-one approach became increasingly difficult to evolve, test, and maintain.

Rather than abandoning the idea of Docker, the project was restructured. This restructuring gave rise to the Moby project, which serves as the open-source upstream for Docker. Think of Moby as the Fedora project is to Red Hat Enterprise Linux (RHEL), the openSUSE project is to SUSE Linux Enterprise, or the Chromium project is to Google Chrome: a place where new ideas can be experimented with and refined before being integrated into the stable, user-facing product. Even if there's a slight difference in these analogies, since Moby is the factory (not just a distribution) for Docker, the comparison still generally holds.

Moby, in reality, is not a replacement for Docker and is not something most users interact with directly. Instead, it provides a modular framework and a collection of building blocks that can be assembled to create container-based platforms. Docker CE (Community Edition) and Docker EE (Enterprise Edition) are built from these components, which is why regular Docker users typically do not notice any difference.

The project provides a set of components and a framework for building customized container systems, both for development and production use. In addition to acting as Docker's upstream, it can also be used independently to build other container runtimes, platforms, and infrastructure systems.

Here are some notable components that are part of this initiative:

• containerd, the industry-standard container runtime responsible for managing the container lifecycle. It's used by Docker and many other platforms.