Docker simplifies the setting up of a server so that it becomes a set of building blocks. And it does so regardless of which server management framework you use

Docker simplifies the setting up of a server so that it becomes a set of building blocks. And it does so regardless of which server management framework you use. This means that you can ditch the more complicated Puppet and Chef and go for a simpler solution like Ansible and still manage a large number of servers. So it is really a different approach to the problem space that Puppet and Chef have attacked. Docker only addresses the building blocks aspect of the problem, and leverages Linux kernel features that most sysadmins have not yet tried to incorporate into their systems. You can either choose to not use a server orchestration framework with Docker and stick with ssh and bash scripts. Or you can choose a lighter framework that is easier to learn and operate like SaltStack or Ansible. Those of use who have run Solaris systems in the past, know the advantages of containerization in partitioning system resources so we tend to be attracted by Docker.