Introduction

In 2006, engineers from Google started working on enabling the running of applications in separated environments on the Linux kernel. This was not a new approach. Similar techniques were used in BSD Jails and Solaris Zones. In 2013, Docker became publicly available. The container revolution started and Docker became a synonymous with container. For developers, containerization meant that they could pack their application with all dependencies and it would run exactly the same as on their machines as it would on their machines. For admins, containers meant less configuration coupling between the machine and applications because applications contained definitions for all dependencies. In the long run, containers are significantly cheaper than virtual machines.