What is Docker Hub?

 Docker Hub is a service provided by Docker for finding and sharing container images. It allows us to push new images and pull existing images from the Hub. DockerHub is like GitHub we can user push/pull commands to manage Docker images. GitHub allows us to store and version controls our source code, while DockerHub allows us to store and version control Docker Images. 

DockerHub is the default registry used by the Docker engine. DockerHub hosts public and private repositories, it also provides automated builds, organization accounts, and integration with source control solutions like Github and Bitbucket. 

A public repository is accessible by anyone running Docker, and image names include the organization/user name. For example, docker pull jenkins will pull the Jenkins CI server image with tag latest from the Jenkins organization. DockerHub supports official repositories, which include images verified for security and best practices. These do not require an organization/user name, for example docker pull nginx will pull the latest image of the Nginx load balancer.
 

DockerHub can perform automated image builds if the DockerHub repository is linked to a source control repository which contains a build context (Dockerfile and all any files in the same folder). A commit in the source repository will trigger a build in DockerHub.