Deployment, management and operationalizing these large complex infrastructures is a daunting task. Containerization of the apps and services helps to simplify these tasks. Docker is open source engine that can help you automate the deployment of applications inside software containers. Is was released in March 2013 and has been gaining popularity ever since. It has been downloaded 13 billion times as of 2017, and over 3.5 million applications have been placed in containers using Docker.