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layout: doc_page title: “Indexing Service”

Indexing Service

The indexing service is a highly-available, distributed service that runs indexing related tasks.

Indexing tasks tasks create (and sometimes destroy) Druid segments. The indexing service has a master/slave like architecture.

The indexing service is composed of three main components: a Peon component that can run a single task, a Middle Manager component that manages peons, and an Overlord component that manages task distribution to middle managers. Overlords and middle managers may run on the same node or across multiple nodes while middle managers and peons always run on the same node.

Tasks are managed using API endpoints on the Overlord service. Please see Overlord Task API for more information.

Overlord

See Overlord.

Middle Managers

See Middle Manager.

Peons

See Peon.

Tasks

See Tasks.