For Middlemanager Node Configuration, see Indexing Service Configuration.
The middle manager node is a worker node that executes submitted tasks. Middle Managers forward tasks to peons that run in separate JVMs. The reason we have separate JVMs for tasks is for resource and log isolation. Each Peon is capable of running only one task at a time, however, a middle manager may have multiple peons.
io.druid.cli.Main server middleManager
For a list of API endpoints supported by the MiddleManager, please see the API reference.