Swarm mode provides the integrated orchestration and clustering capabilities, and with it, the Docker Engine is becoming significantly more powerful. Rather than requiring users to run a separate tool to orchestrate containers, whether that tool is Docker Swarm, Apache Mesos or Kubernetes, the Docker Engine itself is now a reasonably capable orchestration tool.
Docker Inc. representatives at the conference time and again referred to the integration as part of the “democratization” of orchestration and making it more available to the masses. The general thought process is that orchestration today is hard and by providing it as an integrated capability inside the Docker Engine itself, it’s now easier for organizations to benefit.