Apache Mesos, developed at UC Berkeley, is an open-source cluster manager that facilitates resource sharing and isolation across distributed applications by employing a master daemon to manage slave daemons on each cluster node. It supports various frameworks and container formats, with Docker being the most prevalent, and Marathon acts as a container orchestration platform on Mesos. Setting up Mesos and Marathon involves installing several components like Mesos Master and Slave, ZooKeeper, Docker Engine, and Marathon, which can be quite complex. DC/OS, a distributed operating system using Mesos as its kernel, enables running applications such as Couchbase, which can initially be deployed as a single-node but often requires scaling to a multi-node cluster in production. Detailed guides are available for setting up Couchbase clusters on DC/OS, including steps like configuring the CLI, installing a load balancer, and scaling and rebalancing the cluster. Further resources are accessible through Couchbase's developer portal and community forums.