Docker is an open source application container engine, which allows developers to package their applications and dependency packages into a portable image, and then publish it to any popular Linux or Windows machine, and it is also virtualized. Containers use sandbox mechanism completely, and there will be no interface between them.

A complete Docker consists of the following parts:

DockerClient client

Docker daemon.

Docker mirror image

Docker container container.

A typical scene of docker is mentioned on the docker website:

Automate the packaging and deployment of applications.

Create a lightweight and private PAAS environment.

Automated testing and continuous integration/deployment (to achieve automated testing and continuous integration/deployment).

Deploy and extend web applications, databases and back-end services (deploy and extend web applications, databases and back-end services).