Overview

The word "Docker" refers to several things, including an open source community project; tools from the open source project; Docker Inc., the company that primarily supports that project; and the tools that company formally supports. The fact that the technologies and the company share the same name can be confusing.

Here's a brief explainer:

The IT software "Docker” is containerization technology that enables the creation and use of Linux® containers. The open source Docker community works to improve these technologies to benefit all users. The company, Docker Inc., builds on the work of the Docker community, makes it more secure, and shares those advancements back to the greater community. It then supports the improved and hardened technologies for enterprise customers. With Docker, you can treat containers like extremely lightweight, modular virtual machines. And you get flexibility with those containers—you can create, deploy, copy, and move them from environment to environment, which helps optimize your apps for the cloud.

How does Docker work?

The Docker technology uses the Linux kernel and features of the kernel, like Cgroups and namespaces, to segregate processes so they can run independently. This independence is the intention of containers—the ability to run multiple processes and apps separately from one another to make better use of your infrastructure while retaining the security you would have with separate systems.

Container tools, including Docker, provide an image-based deployment model. This makes it easy to share an application, or set of services, with all of their dependencies across multiple environments. Docker also automates deploying the application (or combined sets of processes that make up an app) inside this container environment.

These tools built on top of Linux containers—what makes Docker user-friendly and unique—gives users unprecedented access to apps, the ability to rapidly deploy, and control over versions and version distribution.