What is Docker Registry
By definition, “The Registry is a stateless, highly scalable server side application that stores and lets you distribute Docker images. The Registry is open-source, under the permissive Apache license.”
In other words, a docker registry is a place where we can store our docker images.
Why we need Docker Registry
Provides us a place to store docker images in cloud (if registry is hosted)
Registries can be either public or specific to your organization, which only you can use it.
Images stored can be made available public or private.
With registries, you can integrate image storage and distribution tightly into your in-house development workflow.
What are public and private images
A public image is which can be pulled from a docker registry by anyone anonymously.
A private image is which can be pulled only by the person who has uploaded it. That user has to login to docker before pulling the image.
What is dockerhub
Dockerhub is one of the most popular docker image registry. Check here: Dockerhub
Dockerhub has a huge community and a lot of publically available images for almost anything like java, python, node, etc.