Eunomia - The Elasticsearch Request Prioritizer

Eunomia is a minor Greek god of lawfulness and order.

Overview

This plugin attempts to prioritize requests on an Elasticsearch node based on a number of factors: requested priority, a priority group, how long as the request been waiting, how many active requests are running, what priority groups are currently using the most resources. At the core, Eunomia uses a fair, tiered, burstable, deadlining, queue.

Features

The following are some of the high level features that Eunomia offers (see below for details):

• Tunable Request Priority Queue
• Priority group size policy
• Highly Configurable
• New _cat/prioritized_action endpoint for tracking requests

Install

Current supported versions:

ES Version	Plugin URL
2.3.2	https://github.com/sproutsocial/eunomia/releases/download/v1.0.0-ES2.3.2/eunomia-1.0.0-ES2.3.2.zip

First install the plugin on all nodes in the cluster. Then add transport.service.type: prioritizing-transport-service to the elasticsearch.yml file. Restart all nodes.

Configuration

All configuration options are dynamic.

Option	Default	Description
eunomia.requestPrioritizing.enabled	true	Should requests be prioritized
eunomia.groupThrottling.enabled	true	Should group throttling be enabled
eunomia.groupThrottling.maxGroupSize	1000	Maximum allowed queued requests from a particular group
eunomia.priorityDispatcher.targetActiveRequests	#CPUs - 2	Number of active requests to optimize for
eunomia.priorityDispatcher.deadlineInSeconds	10	Number of seconds a request can be queued before it is "promoted"