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" : "Tamara Rahn",
      "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,
          "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
        }
      }
    }
  }
}

It is also possible to retrieve information for a particular task, or all children of a particular tasks using the following two commands:

GET /_tasks/taskId1
GET /_tasks?parent_task_id=parentTaskId1

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

Task Cancellation

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

POST /_tasks/taskId1/_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?node_id=nodeId1,nodeId2&actions=*reindex