mirror of https://github.com/apache/lucene.git
SOLR-12716: Move common params to top of page; insert links to common param section for each trigger; improve consistency
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Cassandra Targett
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= SolrCloud Autoscaling Triggers
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:page-tocclass: right
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// Licensed to the Apache Software Foundation (ASF) under one
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// or more contributor license agreements. See the NOTICE file
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// distributed with this work for additional information
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@ -16,31 +17,27 @@
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// specific language governing permissions and limitations
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// under the License.
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Triggers are used in autoscaling to watch for cluster events such as nodes joining, leaving, search rate or any other metric breaching a threshold.
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In the future other cluster, node, and replica events that are important from the
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point of view of cluster performance will also have available triggers.
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Triggers are used in autoscaling to watch for cluster events such as nodes joining or leaving, search rate, index rate, on a schedule, or any other metric breaching a threshold.
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Trigger implementations verify the state of resources that they monitor. When they detect a
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change that merits attention they generate events, which are then queued and processed by configured
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`TriggerAction` implementations. This usually involves computing and executing a plan to manage the new cluster
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resources (e.g., move replicas). Solr provides predefined implementations of triggers for specific event types.
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change that merits attention they generate _events_, which are then queued and processed by configured
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`TriggerAction` implementations. This usually involves computing and executing a plan to do something (e.g., move replicas). Solr provides predefined implementations of triggers for <<Event Types,specific event types>>.
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Triggers execute on the node that runs `Overseer`. They are scheduled to run periodically, at a default interval of 1 second between each execution (not every execution produces events).
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Triggers execute on the node that runs `Overseer`. They are scheduled to run periodically, at a default interval of 1 second between each execution (although it's important to note that not every execution of a trigger produces events).
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== Event Types
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Currently the following event types (and corresponding trigger implementations) are defined:
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* `nodeAdded`: generated when a node joins the cluster
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* `nodeLost`: generated when a node leaves the cluster
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* `metric`: generated when the configured metric crosses a configured lower or upper threshold value
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* `nodeAdded`: generated when a node joins the cluster. See <<Node Added Trigger>>.
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* `nodeLost`: generated when a node leaves the cluster. See <<Node Lost Trigger>> and <<Auto Add Replicas Trigger>>.
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* `metric`: generated when the configured metric crosses a configured lower or upper threshold value. See <<Metric Trigger>>.
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* `indexSize`: generated when a shard size (defined as index size in bytes or number of documents)
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exceeds upper or lower threshold values
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* `searchRate`: generated when the search rate exceeds configured upper or lower thresholds
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* `scheduled`: generated according to a scheduled time period such as every 24 hours, etc
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exceeds upper or lower threshold values. See <<Index Size Trigger>>.
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* `searchRate`: generated when the search rate exceeds configured upper or lower thresholds. See <<Search Rate Trigger>>.
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* `scheduled`: generated according to a scheduled time period such as every 24 hours, etc. See <<Scheduled Trigger>>.
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Events are not necessarily generated immediately after the corresponding state change occurred - the
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maximum rate of events is controlled by the `waitFor` configuration parameter (see below).
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Events are not necessarily generated immediately after the corresponding state change occurred; the
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maximum rate of events is controlled by the `waitFor` configuration parameter (see <<Trigger Configuration>> below for more explanation).
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The following properties are common to all event types:
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@ -57,12 +54,82 @@ generated, which may significantly differ due to the rate limits set by `waitFor
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`properties`:: (map, optional) Any additional properties. Currently includes e.g., `nodeNames` property that
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indicates the nodes that were lost or added.
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== Node Added Trigger
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== Trigger Configuration
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Trigger configurations are managed using the <<solrcloud-autoscaling-api.adoc#write-api,Autoscaling Write API>> with the commands `<<solrcloud-autoscaling-api.adoc#create-update-trigger,set-trigger>>`, `<<solrcloud-autoscaling-api.adoc#remove-trigger,remove-trigger>>`,
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`suspend-trigger`, and `resume-trigger`.
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=== Trigger Properties
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Trigger configuration consists of the following properties:
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`name`:: (string, required) A unique trigger configuration name.
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`event`:: (string, required) One of the predefined event types (`nodeAdded` or `nodeLost`).
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`actions`:: (list of action configs, optional) An ordered list of actions to execute when event is fired.
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`waitFor`:: (string, optional) The time to wait between generating new events, as an integer number immediately
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followed by unit symbol, one of `s` (seconds), `m` (minutes), or `h` (hours). Default is `0s`. A condition must
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persist at least for the `waitFor` period to generate an event.
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`enabled`:: (boolean, optional) When `true` the trigger is enabled. Default is `true`.
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Additional implementation-specific properties may be provided, as described in the sections for individual triggers below.
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=== Action Properties
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Action configuration consists of the following properties:
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`name`:: (string, required) A unique name of the action configuration.
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`class`:: (string, required) The action implementation class.
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Additional implementation-specific properties may be provided, as described in the sections for individual triggers below.
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If the `actions` configuration is omitted, then by default, the `ComputePlanAction` and the `ExecutePlanAction` are automatically added to the trigger configuration.
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=== Example Trigger Configuration
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This simple example shows the configuration for adding (or updating) a trigger for `nodeAdded` events.
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[source,json]
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----
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{
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"set-trigger": {
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"name" : "node_added_trigger",
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"event" : "nodeAdded",
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"waitFor" : "1s",
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"enabled" : true,
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"actions" : [
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{
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"name" : "compute_plan",
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"class": "solr.ComputePlanAction"
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},
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{
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"name" : "custom_action",
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"class": "com.example.CustomAction"
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},
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{
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"name" : "execute_plan",
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"class": "solr.ExecutePlanAction"
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}
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]
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}
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}
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----
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This trigger configuration will compute and execute a plan to allocate the resources available on the new node. A custom action could also be used to possibly modify the plan.
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== Available Triggers
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As described earlier, there are several triggers available to watch for events.
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=== Node Added Trigger
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The `NodeAddedTrigger` generates `nodeAdded` events when a node joins the cluster. It can be used to either move replicas
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from other nodes to the new node or to add new replicas.
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Apart from the parameters described at <<#trigger-configuration, Trigger Configuration>>, this trigger supports the following configuration:
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In addition to the parameters described at <<Trigger Configuration>>, this trigger supports one more parameter:
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`preferredOperation`:: (string, optional, defaults to `movereplica`) The operation to be performed in response to an event generated by this trigger. By default, replicas will be moved from other nodes to the added node. The only other supported value is `addreplica` which adds more replicas of the existing collections on the new node.
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@ -91,12 +158,12 @@ Apart from the parameters described at <<#trigger-configuration, Trigger Configu
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}
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----
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== Node Lost Trigger
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=== Node Lost Trigger
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The `NodeLostTrigger` generates `nodeLost` events when a node leaves the cluster. It can be used to either move replicas
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that were hosted by the lost node to other nodes or to delete them from the cluster.
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Apart from the parameters described at <<#trigger-configuration, Trigger Configuration>>, this trigger supports the following configuration:
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In addition to the parameters described at <<Trigger Configuration>>, this trigger supports the one more parameter:
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`preferredOperation`:: (string, optional, defaults to `MOVEREPLICA`) The operation to be performed in response to an event generated by this trigger. By default, replicas will be moved from the lost nodes to the other nodes in the cluster. The only other supported value is `DELETENODE` which deletes all information about replicas that were hosted by the lost node.
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@ -125,9 +192,9 @@ Apart from the parameters described at <<#trigger-configuration, Trigger Configu
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}
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----
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TIP: It is recommended that the value of `waitFor` configuration for node lost trigger be larger than a minute so that large full garbage collection pauses do not cause this trigger to generate events and needlessly move or delete replicas in the cluster.
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TIP: It is recommended that the value of `waitFor` configuration for the node lost trigger be larger than 1 minute so that large full garbage collection pauses do not cause this trigger to generate events and needlessly move or delete replicas in the cluster.
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== Auto Add Replicas Trigger
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=== Auto Add Replicas Trigger
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When a collection has the parameter `autoAddReplicas` set to true then a trigger configuration named `.auto_add_replicas` is automatically created to watch for nodes going away. This trigger produces `nodeLost` events,
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which are then processed by configured actions (usually resulting in computing and executing a plan
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@ -135,32 +202,39 @@ to add replicas on the live nodes to maintain the expected replication factor).
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Refer to the section <<solrcloud-autoscaling-auto-add-replicas.adoc#solrcloud-autoscaling-auto-add-replicas, Autoscaling Automatically Adding Replicas>> to learn more about how the `.autoAddReplicas` trigger works.
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This trigger supports one parameter, which is defined in the `<solrcloud>` section of `solr.xml`:
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In addition to the parameters described at <<Trigger Configuration>>, this trigger supports one parameter, which is defined in the `<solrcloud>` section of `solr.xml`:
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`autoReplicaFailoverWaitAfterExpiration`::
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The minimum time in milliseconds to wait for initiating replacement of a replica after first noticing it not being live. This is important to prevent false positives while stopping or starting the cluster. The default is `120000` (2 minutes). The value provided for this parameter is used as the value for the `waitFor` parameter in the `.auto_add_replicas` trigger.
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TIP: See <<format-of-solr-xml.adoc#the-solrcloud-element,The <solrcloud> Element>> for more details about how to work with `solr.xml`.
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== Metric Trigger
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=== Metric Trigger
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The metric trigger can be used to monitor any metric exposed by the <<metrics-reporting.adoc#metrics-reporting,Metrics API>>. It supports lower and upper threshold configurations as well as optional filters to limit operation to specific collection, shards, and nodes.
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This trigger supports the following configuration:
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In addition to the parameters described at <<Trigger Configuration>>, this trigger supports the following parameters:
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`metric`:: (string, required) The metric property name to be watched in the format metric:__group__:__prefix__, e.g., `metric:solr.node:CONTAINER.fs.coreRoot.usableSpace`.
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`metric`::
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(string, required) The metric property name to be watched in the format metric:__group__:__prefix__, e.g., `metric:solr.node:CONTAINER.fs.coreRoot.usableSpace`.
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`below`:: (double, optional) The lower threshold for the metric value. The trigger produces a metric breached event if the metric's value falls below this value.
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`below`::
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(double, optional) The lower threshold for the metric value. The trigger produces a metric breached event if the metric's value falls below this value.
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`above`:: (double, optional) The upper threshold for the metric value. The trigger produces a metric breached event if the metric's value crosses above this value.
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`above`::
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(double, optional) The upper threshold for the metric value. The trigger produces a metric breached event if the metric's value crosses above this value.
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`collection`:: (string, optional) The collection used to limit the nodes on which the given metric is watched. When the metric is breached, trigger actions will limit operations to this collection only.
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`collection`::
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(string, optional) The collection used to limit the nodes on which the given metric is watched. When the metric is breached, trigger actions will limit operations to this collection only.
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`shard`:: (string, optional) The shard used to limit the nodes on which the given metric is watched. When the metric is breached, trigger actions will limit operations to this shard only.
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`shard`::
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(string, optional) The shard used to limit the nodes on which the given metric is watched. When the metric is breached, trigger actions will limit operations to this shard only.
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`node`:: (string, optional) The node on which the given metric is watched. Trigger actions will operate on this node only.
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`node`::
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(string, optional) The node on which the given metric is watched. Trigger actions will operate on this node only.
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`preferredOperation`:: (string, optional, defaults to `MOVEREPLICA`) The operation to be performed in response to an event generated by this trigger. By default, replicas will be moved from the hot node to others. The only other supported value is `ADDREPLICA` which adds more replicas if the metric is breached.
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`preferredOperation`::
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(string, optional, defaults to `MOVEREPLICA`) The operation to be performed in response to an event generated by this trigger. By default, replicas will be moved from the hot node to others. The only other supported value is `ADDREPLICA` which adds more replicas if the metric is breached.
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.Example: a metric trigger that fires when total usable space on a node having replicas of "mycollection" falls below 100GB
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[source,json]
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}
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----
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== Index Size Trigger
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=== Index Size Trigger
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This trigger can be used for monitoring the size of collection shards, measured either by the
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number of documents in a shard or the physical size of the shard's index in bytes.
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@ -193,34 +267,41 @@ that operation is not yet implemented (see https://issues.apache.org/jira/browse
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Additionally, monitoring can be restricted to a list of collections; by default
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all collections are monitored.
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This trigger supports the following configuration parameters (all thresholds are exclusive):
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In addition to the parameters described at <<Trigger Configuration>>, this trigger supports the following configuration parameters (all thresholds are exclusive):
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`aboveBytes`:: upper threshold in bytes. This value is compared to the `INDEX.sizeInBytes` metric.
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`aboveBytes`::
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A upper threshold in bytes. This value is compared to the `INDEX.sizeInBytes` metric.
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`belowBytes`:: lower threshold in bytes. Note that this value should be at least 2x smaller than
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`belowBytes`::
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A lower threshold in bytes. Note that this value should be at least 2x smaller than
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`aboveBytes`
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`aboveDocs`:: upper threshold expressed as the number of documents. This value is compared with `SEARCHER.searcher.numDocs` metric.
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`aboveDocs`::
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An upper threshold expressed as the number of documents. This value is compared with `SEARCHER.searcher.numDocs` metric.
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+
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NOTE: Due to the way Lucene indexes work, a shard may exceed the `aboveBytes` threshold
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even if the number of documents is relatively small, because replaced and deleted documents keep
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occupying disk space until they are actually removed during Lucene index merging.
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`belowDocs`:: lower threshold expressed as the number of documents.
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`belowDocs`::
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A lower threshold expressed as the number of documents.
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`aboveOp`:: operation to request when an upper threshold is exceeded. If not specified the
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`aboveOp`::
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The operation to request when an upper threshold is exceeded. If not specified the
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default value is `SPLITSHARD`.
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`belowOp`:: operation to request when a lower threshold is exceeded. If not specified
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`belowOp`::
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The operation to request when a lower threshold is exceeded. If not specified
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the default value is `MERGESHARDS` (but see the note above).
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`collections`:: comma-separated list of collection names that this trigger should monitor. If not
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`collections`::
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A comma-separated list of collection names that this trigger should monitor. If not
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specified or empty all collections are monitored.
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Events generated by this trigger contain additional details about the shards
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that exceeded thresholds and the types of violations (upper / lower bounds, bytes / docs metrics).
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.Example:
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.Example: Index Size Trigger
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This configuration specifies an index size trigger that monitors collections "test1" and "test2",
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with both bytes (1GB) and number of docs (1 million) upper limits, and a custom `belowOp`
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operation `NONE` (which still can be monitored and acted upon by an appropriate trigger listener):
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@ -253,7 +334,7 @@ operation `NONE` (which still can be monitored and acted upon by an appropriate
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}
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----
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== Search Rate Trigger
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=== Search Rate Trigger
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The search rate trigger can be used for monitoring search rates in a selected
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collection (1-min average rate by default), and request that either replicas be moved from
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@ -269,82 +350,101 @@ This method was chosen to avoid generating false events when a simple client kee
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to a single specific replica (because adding or removing other replicas can't solve this situation,
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only proper load balancing can - either by using `CloudSolrClient` or another load-balancing client).
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Note: this trigger calculates node-level cumulative rates using per-replica rates reported by
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This trigger calculates node-level cumulative rates using per-replica rates reported by
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replicas that are part of monitored collections / shards on each node. This means that it may report
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some nodes as "cold" (underutilized) because it ignores other, perhaps more active, replicas
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belonging to other collections. Also, nodes that don't host any of the monitored replicas or
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those that are explicitly excluded by `node` config property won't be reported at all.
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Note 2: special care should be taken when configuring `waitFor` property. By default the trigger
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monitors a 1-min average search rate of a replica. Changes to the number of replicas that should in turn
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.Calculating `waitFor`
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[CAUTION]
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====
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Special care should be taken when configuring the `waitFor` property. By default the trigger
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monitors a 1-minute average search rate of a replica. Changes to the number of replicas that should in turn
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change per-replica search rates may be requested and executed relatively quickly if the
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`waitFor` is set to comparable values of 1 min or shorter. However, the metric value, being a
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moving average, will always lag behind the new "momentary" rate after the changes. This in turn means that
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the monitored metric may not change sufficiently enough to prevent the
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trigger from firing again (because it will continue to measure the average rate as still violating
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the threshold for some time after the change was executed). As a result the trigger may keep
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`waitFor` is set to comparable values of 1 min or shorter.
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However, the metric value, being a moving average, will always lag behind the new "momentary" rate after the changes. This in turn means that the monitored metric may not change sufficiently enough to prevent the
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trigger from firing again, because it will continue to measure the average rate as still violating
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the threshold for some time after the change was executed. As a result the trigger may keep
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requesting that even more replicas be added (or removed) and thus it may "overshoot" the optimal number of replicas.
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For this reason it's recommended to always set `waitFor` to values several
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times longer than the time constant of the used metric. For example, with the default 1-min average the
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`waitFor` should be set to at least `2m` or more.
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times longer than the time constant of the used metric. For example, with the default 1-minute average the
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`waitFor` should be set to at least `2m` (2 minutes) or more.
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====
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This trigger supports the following configuration properties:
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In addition to the parameters described at <<Trigger Configuration>>, this trigger supports the following configuration properties:
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`collections`:: (string, optional) comma-separated list of collection names to monitor, or any collection if empty / not set.
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`collections`::
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(string, optional) A comma-separated list of collection names to monitor, or any collection if empty or not set.
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`shard`:: (string, optional) shard name within the collection (requires `collections` to be set to exactly one name), or any shard if empty.
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`shard`::
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(string, optional) A shard name within the collection (requires `collections` to be set to exactly one name), or any shard if empty.
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`node`:: (string, optional) node name to monitor, or any if empty.
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`node`::
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(string, optional) A node name to monitor, or any if empty.
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`metric`:: (string, optional) metric name that represents the search rate
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(default is `QUERY./select.requestTimes:1minRate`). This name has to identify a single numeric
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metric value, and it may use the colon syntax for selecting one property of a complex metric. This value
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is collected from all replicas for a shard, and then an arithmetic average is calculated per shard
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to determine shard-level violations.
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`metric`::
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(string, optional) A metric name that represents the search rate. The default is `QUERY./select.requestTimes:1minRate`. This name has to identify a single numeric metric value, and it may use the colon syntax for selecting one property of
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a complex metric. This value is collected from all replicas for a shard, and then an arithmetic average is calculated
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per shard to determine shard-level violations.
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`maxOps`:: (integer, optional) maximum number of add replica / delete replica operations
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requested in a single autoscaling event. The default value is 3 and it helps to smooth out
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`maxOps`::
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(integer, optional) The maximum number of `ADDREPLICA` or `DELETEREPLICA` operations
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requested in a single autoscaling event. The default value is `3` and it helps to smooth out
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the changes to the number of replicas during periods of large search rate fluctuations.
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`minReplicas`:: (integer, optional) minimum acceptable number of searchable replicas (i.e., replicas other
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than `PULL` type). The trigger will not generate any DELETEREPLICA requests when the number of
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searchable replicas in a shard reaches this threshold. When this value is not set (the default)
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`minReplicas`::
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(integer, optional) The minimum acceptable number of searchable replicas (i.e., replicas other
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than `PULL` type). The trigger will not generate any `DELETEREPLICA` requests when the number of
|
||||
searchable replicas in a shard reaches this threshold.
|
||||
+
|
||||
When this value is not set (the default)
|
||||
the `replicationFactor` property of the collection is used, and if that property is not set then
|
||||
the value is set to 1. Note also that shard leaders are never deleted.
|
||||
the value is set to `1`. Note also that shard leaders are never deleted.
|
||||
|
||||
`aboveRate`:: (float) the upper bound for the request rate metric value. At least one of
|
||||
`aboveRate`::
|
||||
(float) The upper bound for the request rate metric value. At least one of
|
||||
`aboveRate` or `belowRate` must be set.
|
||||
|
||||
`belowRate`:: (float) the lower bound for the request rate metric value. At least one of
|
||||
`belowRate`::
|
||||
(float) The lower bound for the request rate metric value. At least one of
|
||||
`aboveRate` or `belowRate` must be set.
|
||||
|
||||
`aboveNodeRate`:: (float) the upper bound for the total request rate metric value per node. If not
|
||||
`aboveNodeRate`::
|
||||
(float) The upper bound for the total request rate metric value per node. If not
|
||||
set then cumulative per-node rates will be ignored.
|
||||
|
||||
`belowNodeRate`:: (float) the lower bound for the total request rate metric value per node. If not
|
||||
`belowNodeRate`::
|
||||
(float) The lower bound for the total request rate metric value per node. If not
|
||||
set then cumulative per-node rates will be ignored.
|
||||
|
||||
`aboveOp`:: (string, optional) collection action to request when the upper threshold for a shard is
|
||||
`aboveOp`::
|
||||
(string, optional) A collection action to request when the upper threshold for a shard is
|
||||
exceeded. Default action is `ADDREPLICA` and the trigger will request from 1 up to `maxOps` operations
|
||||
per shard per event, proportionally to how much the rate is exceeded. This property can be set to 'NONE'
|
||||
to effectively disable the action but still report it to the listeners.
|
||||
|
||||
`aboveNodeOp`:: (string, optional) collection action to request when the upper threshold for a node (`aboveNodeRate`) is exceeded.
|
||||
`aboveNodeOp`::
|
||||
(string, optional) The collection action to request when the upper threshold for a node (`aboveNodeRate`) is exceeded.
|
||||
Default action is `MOVEREPLICA`, and the trigger will request 1 replica operation per hot node per event.
|
||||
If both `aboveOp` and `aboveNodeOp` operations are to be requested then `aboveNodeOp` operations are
|
||||
always requested first, and only if no `aboveOp` (shard level) operations are to be requested (because `aboveOp`
|
||||
operations will change node-level rates anyway). This property can be set to 'NONE' to effectively disable
|
||||
the action but still report it to the listeners.
|
||||
|
||||
`belowOp`:: (string, optional) collection action to request when the lower threshold for a shard is
|
||||
`belowOp`::
|
||||
(string, optional) The collection action to request when the lower threshold for a shard is
|
||||
exceeded. Default action is `DELETEREPLICA`, and the trigger will request at most `maxOps` replicas
|
||||
to be deleted from eligible cold shards. This property can be set to 'NONE'
|
||||
to effectively disable the action but still report it to the listeners.
|
||||
|
||||
`belowNodeOp`:: action to request when the lower threshold for a node (`belowNodeRate`) is exceeded.
|
||||
`belowNodeOp`::
|
||||
(string, optional) The action to request when the lower threshold for a node (`belowNodeRate`) is exceeded.
|
||||
Default action is null (not set) and the condition is ignored, because in many cases the
|
||||
trigger will monitor only some selected resources (replicas from selected
|
||||
collections / shards) so setting this by default to e.g., `DELETENODE` could interfere with
|
||||
collections or shards) so setting this by default to e.g., `DELETENODE` could interfere with
|
||||
these non-monitored resources. The trigger will request 1 operation per cold node per event.
|
||||
If both `belowOp` and `belowNodeOp` operations are requested then `belowOp` operations are
|
||||
always requested first.
|
||||
|
|
@ -355,6 +455,7 @@ average request rate of "/select" handler exceeds 100 requests/sec, and the cond
|
|||
for over 20 minutes. If the rate falls below 0.01 and persists for 20 min the trigger will
|
||||
request not only replica deletions (leaving at most 1 replica per shard) but also it may
|
||||
request node deletion.
|
||||
|
||||
[source,json]
|
||||
----
|
||||
{
|
||||
|
|
@ -384,11 +485,11 @@ request node deletion.
|
|||
}
|
||||
----
|
||||
|
||||
== Scheduled Trigger
|
||||
=== Scheduled Trigger
|
||||
|
||||
The Scheduled trigger generates events according to a fixed rate schedule.
|
||||
|
||||
The trigger supports the following configuration:
|
||||
In addition to the parameters described at <<Trigger Configuration>>, this trigger supports the following configuration:
|
||||
|
||||
`startTime`::
|
||||
(string, required) The start date/time of the schedule. This should either be a DateMath string e.g., 'NOW', or be an ISO-8601 date time string (the same standard used during search and indexing in Solr, which defaults to UTC), or be specified without the trailing 'Z' accompanied with the `timeZone` parameter. For example, each of the following values are acceptable:
|
||||
|
|
@ -410,65 +511,6 @@ The trigger supports the following configuration:
|
|||
|
||||
This trigger applies the `every` date math expression on the `startTime` or the last event time to derive the next scheduled time and if current time is greater than next scheduled time but within `graceTime` then an event is generated.
|
||||
|
||||
Apart from the common event properties described in the Event Types section, the trigger adds an additional `actualEventTime` event property which has the actual event time as opposed to the scheduled time.
|
||||
Apart from the common event properties described in the <<Event Types>> section, the trigger adds an additional `actualEventTime` event property which has the actual event time as opposed to the scheduled time.
|
||||
|
||||
For example, if the scheduled time was `2018-01-31T15:30:00Z` and grace time was `+15MINUTES` then an event may be fired at `2018-01-31T15:45:00Z`. Such an event will have `eventTime` as `2018-01-31T15:30:00Z`, the scheduled time, but the `actualEventTime` property will have a value of `2018-01-31T15:45:00Z`, the actual time.
|
||||
|
||||
== Trigger Configuration
|
||||
Trigger configurations are managed using the Autoscaling Write API and the commands `set-trigger`, `remove-trigger`,
|
||||
`suspend-trigger`, and `resume-trigger`.
|
||||
|
||||
Trigger configuration consists of the following properties:
|
||||
|
||||
`name`:: (string, required) A unique trigger configuration name.
|
||||
|
||||
`event`:: (string, required) One of the predefined event types (`nodeAdded` or `nodeLost`).
|
||||
|
||||
`actions`:: (list of action configs, optional) An ordered list of actions to execute when event is fired.
|
||||
|
||||
`waitFor`:: (string, optional) The time to wait between generating new events, as an integer number immediately
|
||||
followed by unit symbol, one of `s` (seconds), `m` (minutes), or `h` (hours). Default is `0s`. A condition must
|
||||
persist at least for the `waitFor` period to generate an event.
|
||||
|
||||
`enabled`:: (boolean, optional) When `true` the trigger is enabled. Default is `true`.
|
||||
|
||||
Additional implementation-specific properties may be provided.
|
||||
|
||||
Action configuration consists of the following properties:
|
||||
|
||||
`name`:: (string, required) A unique name of the action configuration.
|
||||
|
||||
`class`:: (string, required) The action implementation class.
|
||||
|
||||
Additional implementation-specific properties may be provided
|
||||
|
||||
If the `actions` configuration is omitted, then by default, the `ComputePlanAction` and the `ExecutePlanAction` are automatically added to the trigger configuration.
|
||||
|
||||
.Example: adding or updating a trigger for `nodeAdded` events
|
||||
[source,json]
|
||||
----
|
||||
{
|
||||
"set-trigger": {
|
||||
"name" : "node_added_trigger",
|
||||
"event" : "nodeAdded",
|
||||
"waitFor" : "1s",
|
||||
"enabled" : true,
|
||||
"actions" : [
|
||||
{
|
||||
"name" : "compute_plan",
|
||||
"class": "solr.ComputePlanAction"
|
||||
},
|
||||
{
|
||||
"name" : "custom_action",
|
||||
"class": "com.example.CustomAction"
|
||||
},
|
||||
{
|
||||
"name" : "execute_plan",
|
||||
"class": "solr.ExecutePlanAction"
|
||||
}
|
||||
]
|
||||
}
|
||||
}
|
||||
----
|
||||
|
||||
This trigger configuration will compute and execute a plan to allocate the resources available on the new node. A custom action is also used to possibly modify the plan.
|
||||
|
|
|
|||
Loading…
Reference in New Issue