# What is Docker Docker is **an open platform for developing, shipping, and running applications**. Docker enables you to separate your applications from your infrastructure so you can deliver software quickly. With Docker, you can manage your infrastructure in the same ways you manage your applications. ## Docker Image A Docker image contains **application code, libraries, tools, dependencies and other files needed to make an application run**. When a user runs an image, it can become one or many instances of a container. ## **Docker Store/Docker Hub** Online cloud service where you can store and share docker images. ## **Docker Engine** Comprised of runtime and packaging tool. Must be installed on hosts running docker