What is Docker Registry?

A Docker Registry is a storage and distribution system for named Docker images. The Docker registry is used to store the static Docker image templates. The same image might have multiple different versions, identified by their tags. 

A Docker Registry is organized into Docker repositories, where a repository holds all the versions of a specific image. The registry allows Docker users to pull images locally, as well as push new images to the registry. 

DockerHub is the default registry used by the Docker engine, it is the Docker's public registry instance. It is possible to run on-premise the open-source Docker registry/distribution, as well as a commercially supported version called Docker Trusted Registry

What is Docker?

Docker is an open platform to create, deploy and run applications by using Containers. Docker makes is easy to deploy applications from one environment to another. Containers allow a developer to package up an application with all of the parts it needs, such as libraries and other dependencies, and deploy it as one package.

Docker can be seen as an improvement to a Virtual machine. Each Virtual Machine in a server needs a separate Guest operating system to function. All the Docker Containers in a server use the same underlying Operating System of the server, hence Dockers are lightweight when compared to Virtual Machines. Also, Dockers are faster to spin up and execute when compared to Virtual Machines.

The Docker platform contains the following components