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Elastic Docs ›Elasticsearch Guide [5.0] ›Cluster APIs

Task Management API

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Task Management API

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The Task Management API is new and should still be considered experimental. The API may change in ways that are not backwards compatible

Current Tasks Information

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The task management API allows to retrieve information about the tasks currently executing on one or more nodes in the cluster.

GET _tasks 
GET _tasks?nodes=nodeId1,nodeId2 
GET _tasks?nodes=nodeId1,nodeId2&actions=cluster:*

Retrieves all tasks currently running on all nodes in the cluster.

Retrieves all tasks running on nodes nodeId1 and nodeId2. See Node specification for more info about how to select individual nodes.

Retrieves all cluster-related tasks running on nodes nodeId1 and nodeId2.

The result will look similar to the following:

{
  "nodes" : {
    "oTUltX4IQMOUUVeiohTt8A" : {
      "name" : "H5dfFeA",
      "transport_address" : "127.0.0.1:9300",
      "host" : "127.0.0.1",
      "ip" : "127.0.0.1:9300",
      "tasks" : {
        "oTUltX4IQMOUUVeiohTt8A:124" : {
          "node" : "oTUltX4IQMOUUVeiohTt8A",
          "id" : 124,
          "type" : "direct",
          "action" : "cluster:monitor/tasks/lists[n]",
          "start_time_in_millis" : 1458585884904,
          "running_time_in_nanos" : 47402,
          "cancellable" : false,
          "parent_task_id" : "oTUltX4IQMOUUVeiohTt8A:123"
        },
        "oTUltX4IQMOUUVeiohTt8A:123" : {
          "node" : "oTUltX4IQMOUUVeiohTt8A",
          "id" : 123,
          "type" : "transport",
          "action" : "cluster:monitor/tasks/lists",
          "start_time_in_millis" : 1458585884904,
          "running_time_in_nanos" : 236042,
          "cancellable" : false
        }
      }
    }
  }
}

It is also possible to retrieve information for a particular task:

GET _tasks/task_id:1

This will return a 404 if the task isn’t found.

Or to retrieve all children of a particular task:

GET _tasks?parent_task_id=parentTaskId:1

This won’t return a 404 if the parent isn’t found.

The task API can be also used to wait for completion of a particular task. The following call will block for 10 seconds or until the task with id oTUltX4IQMOUUVeiohTt8A:12345 is completed.

GET _tasks/oTUltX4IQMOUUVeiohTt8A:12345?wait_for_completion=true&timeout=10s

You can also wait for all tasks for certain action types to finish. This command will wait for all reindex tasks to finish:

GET _tasks?actions=*reindex&wait_for_completion=true&timeout=10s

Tasks can be also listed using _cat version of the list tasks command, which accepts the same arguments as the standard list tasks command.

GET _cat/tasks

Task Cancellation

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If a long-running task supports cancellation, it can be cancelled by the following command:

POST _tasks/task_id:1/_cancel

The task cancellation command supports the same task selection parameters as the list tasks command, so multiple tasks can be cancelled at the same time. For example, the following command will cancel all reindex tasks running on the nodes nodeId1 and nodeId2.

POST _tasks/_cancel?nodes=nodeId1,nodeId2&actions=*reindex

Task Grouping

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The task lists returned by task API commands can be grouped either by nodes (default) or by parent tasks using the group_by parameter. The following command will change the grouping to parent tasks:

GET _tasks?group_by=parents
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