Docker is a set of platform as a service (PaaS) products that use OS-level virtualization to deliver software in packages called containers.[5] The service has both free and premium tiers. The software that hosts the containers is called Docker Engine.[6] It was first released in 2013 and is developed by Docker, Inc.[7]
Docker is a tool that is used to automate the deployment of applications in lightweight containers so that applications can work efficiently in different environments in isolation.