Could anyone point out the boundary between the open-source Mesos / Marathon stack, and the commercial DC/OS? The official documentation (https://docs.mesospher

Could anyone point out the boundary between the open-source Mesos / Marathon stack, and the commercial DC/OS? The official documentation (https://docs.mesosphere.com/1.9/overview/what-is-dcos/ https://docs.mesosphere.com/1.9/overview/what-is-dcos/) doesn't make it clear. What capabilities does DC/OS have that are not available in the open-source portion of the stack? > As a distributed system, DC/OS includes a group of agent nodes that are coordinated by a group of master nodes. Like other distributed systems, several of the components running on the master nodes perform leader election with their peers. This just sounds like vanilla Mesos masters and slaves. DC/OS "runs on top of" that, but what is it actually doing? Is the DC/OS another service that just enables the Mesos masters to initially discover and replace each other? Could it not be replaced with Zookeeper or Consul? That seems like a small piece of the puzzle, what would make it the one expensive thing, while the rest of the system is free? Is the overall stack actually shareware, rather than a community of independent open-source services? The reason I am so curious, is because after running a small demo a year ago, the Mesos stack looked really promising. The only thing holding me back from proposing a large scale trial, for comparison to our sprawling Heroku/ECS/EBS setup, was the feeling that I was not understanding a crucial part of the architecture, and not understanding the pricing, if that is even applicable (couldn't find price info anywhere! How do I quantify that part?)