For general Coordinator Node information, see here.
The coordinator node uses several of the global configs in Configuration and has the following set of configurations as well:
| Property | Description | Default |
|---|---|---|
druid.host | The host for the current node. This is used to advertise the current processes location as reachable from another node and should generally be specified such that http://${druid.host}/ could actually talk to this process | InetAddress.getLocalHost().getCanonicalHostName() |
druid.plaintextPort | This is the port to actually listen on; unless port mapping is used, this will be the same port as is on druid.host | 8081 |
druid.tlsPort | TLS port for HTTPS connector, if druid.enableTlsPort is set then this config will be used. If druid.host contains port then that port will be ignored. This should be a non-negative Integer. | 8281 |
druid.service | The name of the service. This is used as a dimension when emitting metrics and alerts to differentiate between the various services | druid/coordinator |
| Property | Description | Default |
|---|---|---|
druid.coordinator.period | The run period for the coordinator. The coordinator’s operates by maintaining the current state of the world in memory and periodically looking at the set of segments available and segments being served to make decisions about whether any changes need to be made to the data topology. This property sets the delay between each of these runs. | PT60S |
druid.coordinator.period.indexingPeriod | How often to send indexing tasks to the indexing service. Only applies if merge or conversion is turned on. | PT1800S (30 mins) |
druid.coordinator.startDelay | The operation of the Coordinator works on the assumption that it has an up-to-date view of the state of the world when it runs, the current ZK interaction code, however, is written in a way that doesn’t allow the Coordinator to know for a fact that it’s done loading the current state of the world. This delay is a hack to give it enough time to believe that it has all the data. | PT300S |
druid.coordinator.merge.on | Boolean flag for whether or not the coordinator should try and merge small segments into a more optimal segment size. | false |
druid.coordinator.conversion.on | Boolean flag for converting old segment indexing versions to the latest segment indexing version. | false |
druid.coordinator.load.timeout | The timeout duration for when the coordinator assigns a segment to a historical node. | PT15M |
druid.coordinator.kill.pendingSegments.on | Boolean flag for whether or not the coordinator clean up old entries in the pendingSegments table of metadata store. If set to true, coordinator will check the created time of most recently complete task. If it doesn't exist, it finds the created time of the earlist running/pending/waiting tasks. Once the created time is found, then for all dataSources not in the killPendingSegmentsSkipList (see Dynamic configuration), coordinator will ask the overlord to clean up the entries 1 day or more older than the found created time in the pendingSegments table. This will be done periodically based on druid.coordinator.period specified. | false |
druid.coordinator.kill.on | Boolean flag for whether or not the coordinator should submit kill task for unused segments, that is, hard delete them from metadata store and deep storage. If set to true, then for all whitelisted dataSources (or optionally all), coordinator will submit tasks periodically based on period specified. These kill tasks will delete all segments except for the last durationToRetain period. Whitelist or All can be set via dynamic configuration killAllDataSources and killDataSourceWhitelist described later. | false |
druid.coordinator.kill.period | How often to send kill tasks to the indexing service. Value must be greater than druid.coordinator.period.indexingPeriod. Only applies if kill is turned on. | P1D (1 Day) |
druid.coordinator.kill.durationToRetain | Do not kill segments in last durationToRetain, must be greater or equal to 0. Only applies and MUST be specified if kill is turned on. Note that default value is invalid. | PT-1S (-1 seconds) |
druid.coordinator.kill.maxSegments | Kill at most n segments per kill task submission, must be greater than 0. Only applies and MUST be specified if kill is turned on. Note that default value is invalid. | 0 |
druid.coordinator.balancer.strategy | Specify the type of balancing strategy that the coordinator should use to distribute segments among the historicals. cachingCost is logically equivalent to cost but is more CPU-efficient on large clusters and will replace cost in the future versions, users are invited to try it. Use diskNormalized to distribute segments among nodes so that the disks fill up uniformly and use random to randomly pick nodes to distribute segments. | cost |
druid.coordinator.loadqueuepeon.repeatDelay | The start and repeat delay for the loadqueuepeon , which manages the load and drop of segments. | PT0.050S (50 ms) |
druid.coordinator.asOverlord.enabled | Boolean value for whether this coordinator node should act like an overlord as well. This configuration allows users to simplify a druid cluster by not having to deploy any standalone overlord nodes. If set to true, then overlord console is available at http://coordinator-host:port/console.html and be sure to set druid.coordinator.asOverlord.overlordService also. See next. | false |
druid.coordinator.asOverlord.overlordService | Required, if druid.coordinator.asOverlord.enabled is true. This must be same value as druid.service on standalone Overlord nodes and druid.selectors.indexing.serviceName on Middle Managers. | NULL |
| Property | Possible Values | Description | Default |
|---|---|---|---|
druid.announcer.type | batch or http | Segment discovery method to use. “http” enables discovering segments using HTTP instead of zookeeper. | batch |
druid.coordinator.loadqueuepeon.type | curator or http | Whether to use “http” or “curator” implementation to assign segment loads/drops to historical | curator |
| Property | Description | Default |
|---|---|---|
druid.coordinator.loadqueuepeon.http.batchSize | Number of segment load/drop requests to batch in one HTTP request. Note that it must be smaller than druid.segmentCache.numLoadingThreads config on historical node. | 1 |
| Property | Description | Default |
|---|---|---|
druid.manager.config.pollDuration | How often the manager polls the config table for updates. | PT1m |
druid.manager.segments.pollDuration | The duration between polls the Coordinator does for updates to the set of active segments. Generally defines the amount of lag time it can take for the coordinator to notice new segments. | PT1M |
druid.manager.rules.pollDuration | The duration between polls the Coordinator does for updates to the set of active rules. Generally defines the amount of lag time it can take for the coordinator to notice rules. | PT1M |
druid.manager.rules.defaultTier | The default tier from which default rules will be loaded from. | _default |
druid.manager.rules.alertThreshold | The duration after a failed poll upon which an alert should be emitted. | PT10M |
The coordinator has dynamic configuration to change certain behaviour on the fly. The coordinator uses a JSON spec object from the Druid metadata storage config table. This object is detailed below:
It is recommended that you use the Coordinator Console to configure these parameters. However, if you need to do it via HTTP, the JSON object can be submitted to the coordinator via a POST request at:
http://<COORDINATOR_IP>:<PORT>/druid/coordinator/v1/config
Optional Header Parameters for auditing the config change can also be specified.
| Header Param Name | Description | Default |
|---|---|---|
X-Druid-Author | author making the config change | "" |
X-Druid-Comment | comment describing the change being done | "" |
A sample coordinator dynamic config JSON object is shown below:
{ "millisToWaitBeforeDeleting": 900000, "mergeBytesLimit": 100000000, "mergeSegmentsLimit" : 1000, "maxSegmentsToMove": 5, "replicantLifetime": 15, "replicationThrottleLimit": 10, "emitBalancingStats": false, "killDataSourceWhitelist": ["wikipedia", "testDatasource"] }
Issuing a GET request at the same URL will return the spec that is currently in place. A description of the config setup spec is shown below.
| Property | Description | Default |
|---|---|---|
millisToWaitBeforeDeleting | How long does the coordinator need to be active before it can start removing (marking unused) segments in metadata storage. | 900000 (15 mins) |
mergeBytesLimit | The maximum total uncompressed size in bytes of segments to merge. | 524288000L |
mergeSegmentsLimit | The maximum number of segments that can be in a single append task. | 100 |
maxSegmentsToMove | The maximum number of segments that can be moved at any given time. | 5 |
replicantLifetime | The maximum number of coordinator runs for a segment to be replicated before we start alerting. | 15 |
replicationThrottleLimit | The maximum number of segments that can be replicated at one time. | 10 |
emitBalancingStats | Boolean flag for whether or not we should emit balancing stats. This is an expensive operation. | false |
killDataSourceWhitelist | List of dataSources for which kill tasks are sent if property druid.coordinator.kill.on is true. This can be a list of comma-separated dataSources or a JSON array. | none |
killAllDataSources | Send kill tasks for ALL dataSources if property druid.coordinator.kill.on is true. If this is set to true then killDataSourceWhitelist must not be specified or be empty list. | false |
killPendingSegmentsSkipList | List of dataSources for which pendingSegments are NOT cleaned up if property druid.coordinator.kill.pendingSegments.on is true. This can be a list of comma-separated dataSources or a JSON array. | none |
maxSegmentsInNodeLoadingQueue | The maximum number of segments that could be queued for loading to any given server. This parameter could be used to speed up segments loading process, especially if there are “slow” nodes in the cluster (with low loading speed) or if too much segments scheduled to be replicated to some particular node (faster loading could be preferred to better segments distribution). Desired value depends on segments loading speed, acceptable replication time and number of nodes. Value 1000 could be a start point for a rather big cluster. Default value is 0 (loading queue is unbounded) | 0 |
To view the audit history of coordinator dynamic config issue a GET request to the URL -
http://<COORDINATOR_IP>:<PORT>/druid/coordinator/v1/config/history?interval=<interval>
default value of interval can be specified by setting druid.audit.manager.auditHistoryMillis (1 week if not configured) in coordinator runtime.properties
To view last entries of the audit history of coordinator dynamic config issue a GET request to the URL -
http://<COORDINATOR_IP>:<PORT>/druid/coordinator/v1/config/history?count=<n>
These configuration options control the behavior of the Lookup dynamic configuration described in the lookups page
| Property | Description | Default |
|---|---|---|
druid.manager.lookups.hostDeleteTimeout | How long to wait for a DELETE request to a particular node before considering the DELETE a failure | PT1s |
druid.manager.lookups.hostUpdateTimeout | How long to wait for a POST request to a particular node before considering the POST a failure | PT10s |
druid.manager.lookups.deleteAllTimeout | How long to wait for all DELETE requests to finish before considering the delete attempt a failure | PT10s |
druid.manager.lookups.updateAllTimeout | How long to wait for all POST requests to finish before considering the attempt a failure | PT60s |
druid.manager.lookups.threadPoolSize | How many nodes can be managed concurrently (concurrent POST and DELETE requests). Requests this limit will wait in a queue until a slot becomes available. | 10 |
druid.manager.lookups.period | How many milliseconds between checks for configuration changes | 30_000 |