The Docker Hub provides both a public and private repository. The public repository is free to users and private is a paid service. The plans with private repositories are available in different sizes, such as a micro, small, medium, or large subscription.

Docker has published their public repository code to open source at https://github.com/docker/docker-registry.

Normally, enterprises will not like to keep their Docker images either in a Docker public or private repository. They prefer to keep, maintain, and support their own repository. Hence, Docker also provides the option for enterprises to create and install their own repository.

Let's create a repository in the local machine using the registry image provided by Docker. We will run the registry container on the local machine, using the registry image from Docker:

$ sudo docker run -p 5000:5000 -d registry
768fb5bcbe3a5a774f4996f0758151b1e9917dec21aedf386c5742d44beafa41

In the automated build section...