druid/docs/content/Indexing-Service-Config.md

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For general Indexing Service information, see here.

Runtime Configuration

In addition to the configuration of some of the default modules in Configuration, the overlord has the following basic configs:

Property	Description	Default
druid.indexer.runner.type	Choices "local" or "remote". Indicates whether tasks should be run locally or in a distributed environment.	local
druid.indexer.storage.type	Choices are "local" or "db". Indicates whether incoming tasks should be stored locally (in heap) or in a database. Storing incoming tasks in a database allows for tasks to be resumed if the overlord should fail.	local
druid.indexer.storage.recentlyFinishedThreshold	A duration of time to store task results.	PT24H
druid.indexer.queue.maxSize	Maximum number of active tasks at one time.	Integer.MAX_VALUE
druid.indexer.queue.startDelay	Sleep this long before starting overlord queue management. This can be useful to give a cluster time to re-orient itself after e.g. a widespread network issue.	PT1M
druid.indexer.queue.restartDelay	Sleep this long when overlord queue management throws an exception before trying again.	PT30S
druid.indexer.queue.storageSyncRate	Sync overlord state this often with an underlying task persistence mechanism.	PT1M

The following configs only apply if the overlord is running in remote mode:

Property	Description	Default
druid.indexer.runner.taskAssignmentTimeout	How long to wait after a task as been assigned to a middle manager before throwing an error.	PT5M
druid.indexer.runner.minWorkerVersion	The minimum middle manager version to send tasks to.	"0"
druid.indexer.runner.compressZnodes	Indicates whether or not the overlord should expect middle managers to compress Znodes.	false
druid.indexer.runner.maxZnodeBytes	The maximum size Znode in bytes that can be created in Zookeeper.	524288

There are additional configs for autoscaling (if it is enabled):

Property	Description	Default
druid.indexer.autoscale.strategy	Choices are "noop" or "ec2". Sets the strategy to run when autoscaling is required.	noop
druid.indexer.autoscale.doAutoscale	If set to "true" autoscaling will be enabled.	false
druid.indexer.autoscale.provisionPeriod	How often to check whether or not new middle managers should be added.	PT1M
druid.indexer.autoscale.terminatePeriod	How often to check when middle managers should be removed.	PT1H
druid.indexer.autoscale.originTime	The starting reference timestamp that the terminate period increments upon.	2012-01-01T00:55:00.000Z
druid.indexer.autoscale.workerIdleTimeout	How long can a worker be idle (not a run task) before it can be considered for termination.	PT10M
druid.indexer.autoscale.maxScalingDuration	How long the overlord will wait around for a middle manager to show up before giving up.	PT15M
druid.indexer.autoscale.numEventsToTrack	The number of autoscaling related events (node creation and termination) to track.	10
druid.indexer.autoscale.pendingTaskTimeout	How long a task can be in "pending" state before the overlord tries to scale up.	PT30S
druid.indexer.autoscale.workerVersion	If set, will only create nodes of set version during autoscaling. Overrides dynamic configuration.	null
druid.indexer.autoscale.workerPort	The port that middle managers will run on.	8080

Dynamic Configuration

Overlord dynamic configuration is mainly for autoscaling. The overlord reads a worker setup spec as a JSON object from the Druid MySQL config table. This object contains information about the version of middle managers to create, the maximum and minimum number of middle managers in the cluster at one time, and additional information required to automatically create middle managers.

The JSON object can be submitted to the overlord via a POST request at:

http://<COORDINATOR_IP>:<port>/druid/indexer/v1/worker/setup

A sample worker setup spec is shown below:

{
  "minVersion":"some_version",
  "minNumWorkers":"0",
  "maxNumWorkers":"10",
  "nodeData": {
    "type":"ec2",
    "amiId":"ami-someId",
    "instanceType":"m1.xlarge",
    "minInstances":"1",
    "maxInstances":"1",
    "securityGroupIds":["securityGroupIds"],
    "keyName":"keyName"
  },
  "userData":{
    "impl":"string",
    "data":"version=:VERSION:",
    "versionReplacementString":":VERSION:"
  }
}

Issuing a GET request at the same URL will return the current worker setup spec that is currently in place. The worker setup spec list above is just a sample and it is possible to extend the code base for other deployment environments. A description of the worker setup spec is shown below.

Property	Description	Default
minNumWorkers	The minimum number of workers that can be in the cluster at any given time.	0
maxNumWorkers	The maximum number of workers that can be in the cluster at any given time.	0
nodeData	A JSON object that describes how to launch new nodes. Currently, only EC2 is supported.	none; required
userData	A JSON object that describes how to configure new nodes. Currently, only EC2 is supported. If you have set druid.indexer.autoscale.workerVersion, this must have a versionReplacementString. Otherwise, a versionReplacementString is not necessary.	none; optional