The Big Picture - moby/moby - libcontainer

The Moby Project is an open-source initiative by Docker to advance the software containerization movement. It provides a library of components, a framework for assembling them into custom container-based systems, and a place for the container community to experiment and exchange ideas. In this documentation, we will focus on the role and significance of libcontainer within the Moby Project.

Background

Docker was initially a monolithic application, with the Docker engine handling all containerization tasks. However, with the release of Docker Engine v1.11, the monolith was decoupled into independent components, leading to the creation of the Moby Project. The Moby Project serves as an R&D lab for Docker, where new components are developed and collaborated upon with the ecosystem.

Libcontainer

Libcontainer is a crucial component of the Moby Project, responsible for the container runtime. It provides the underlying mechanism for running containers, managing their lifecycle, and isolating processes. Libcontainer is designed to be lightweight, efficient, and flexible, allowing users to build their own container systems using the Moby library or their own components.

Key Features and Components

Docker Engine

Docker Engine is the primary user interface for interacting with the Moby Project. It is still the recommended way for users to build, ship, and run containers. However, all open source collaboration and development will now take place within the Moby Project.

BuildKit

BuildKit is a component of the Moby Project that focuses on building container images. It is designed to be faster, more secure, and more flexible than the traditional Docker build process. BuildKit allows users to build images in parallel, cache intermediate results, and use multiple buildx workers for improved performance.

SLSA Definitions

The Software Supply Chain Security (SLSA) initiative provides definitions and guidelines for securing the software supply chain. The Moby Project supports SLSA by providing provenance attestations for container images built using BuildKit. These attestations include information about the build process, such as the build invocation ID, start and finish times, and reproducibility status.

Other Projects and Tools

The Moby Project is not limited to libcontainer and BuildKit. It also includes other components and tools, such as the Moby Origin reference assembly, which serves as the open base for the Docker container platform, and the Kyverno policy engine, which can be used to enforce container image security policies.

Conclusion

Libcontainer is a vital component of the Moby Project, providing the underlying container runtime functionality. It is part of a larger ecosystem of open-source projects and tools designed to advance the software containerization movement and help users build, ship, and run containers more efficiently and securely. By focusing on the big picture and understanding the role of libcontainer within the Moby Project, you will be better equipped to learn, make informed decisions, and apply your knowledge in real-world scenarios.