--- id: middlemanager title: "MiddleManager service" sidebar_label: "MiddleManager" --- <!-- ~ Licensed to the Apache Software Foundation (ASF) under one ~ or more contributor license agreements. See the NOTICE file ~ distributed with this work for additional information ~ regarding copyright ownership. The ASF licenses this file ~ to you under the Apache License, Version 2.0 (the ~ "License"); you may not use this file except in compliance ~ with the License. You may obtain a copy of the License at ~ ~ http://www.apache.org/licenses/LICENSE-2.0 ~ ~ Unless required by applicable law or agreed to in writing, ~ software distributed under the License is distributed on an ~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY ~ KIND, either express or implied. See the License for the ~ specific language governing permissions and limitations ~ under the License. --> The MiddleManager service is a worker service that executes submitted tasks. MiddleManagers forward tasks to [Peons](../design/peons.md) that run in separate JVMs. Druid uses separate JVMs for tasks to isolate resources and logs. Each Peon is capable of running only one task at a time, wheres a MiddleManager may have multiple Peons. ## Configuration For Apache Druid MiddleManager service configuration, see [MiddleManager and Peons](../configuration/index.md#middlemanager-and-peons). For basic tuning guidance for the MiddleManager service, see [Basic cluster tuning](../operations/basic-cluster-tuning.md#middlemanager). ## HTTP endpoints For a list of API endpoints supported by the MiddleManager, see the [Service status API reference](../api-reference/service-status-api.md#middlemanager). ## Running ``` org.apache.druid.cli.Main server middleManager ```