Task start event

This event is emitted once a task has been scheduled to start on a compute node by the scheduler. Note that if the task is retried or requeued this event will be emitted again for the same task, but the retry count and system task version will be updated accordingly.

The following example shows the body of a task start event.

{
    "jobId": "myJob",
    "id": "myTask",
    "taskType": "User",
    "systemTaskVersion": 220192842,
    "requiredSlots": 1,
    "nodeInfo": {
        "poolId": "pool-001",
        "nodeId": "tvm-257509324_1-20160908t162728z"
    },
    "multiInstanceSettings": {
        "numberOfInstances": 1
    },
    "constraints": {
        "maxTaskRetryCount": 2
    },
    "executionInfo": {
        "retryCount": 0
    }
}

Element name	Type	Notes
jobId	String	The ID of the job containing the task.
id	String	The ID of the task.
taskType	String	The type of the task. This can either be 'JobManager' indicating it is a job manager task or 'User' indicating it is not a job manager task.
systemTaskVersion	Int32	This is the internal retry counter on a task. Internally the Batch service can retry a task to account for transient issues. These issues can include internal scheduling errors or attempts to recover from compute nodes in a bad state.
requiredSlots	Int32	The required slots to run the task.
nodeInfo	Complex Type	Contains information about the compute node on which the task ran.
multiInstanceSettings	Complex Type	Specifies that the task is Multi-Instance Task requiring multiple compute nodes. See multiInstanceSettings for details.
constraints	Complex Type	The execution constraints that apply to this task.
executionInfo	Complex Type	Contains information about the execution of the task.

nodeInfo

Element name	Type	Notes
poolId	String	The ID of the pool on which the task ran.
nodeId	String	The ID of the node on which the task ran.

multiInstanceSettings

Element name	Type	Notes
numberOfInstances	Int	The number of compute nodes required by the task.

constraints

Element name	Type	Notes
maxTaskRetryCount	Int32	The maximum number of times the task may be retried. The Batch service retries a task if its exit code is nonzero. Note that this value specifically controls the number of retries. The Batch service will try the task once, and may then retry up to this limit. For example, if the maximum retry count is 3, Batch tries a task up to 4 times (one initial try and 3 retries). If the maximum retry count is 0, the Batch service does not retry tasks. If the maximum retry count is -1, the Batch service retries tasks without limit. The default value is 0 (no retries).

executionInfo

Element name	Type	Notes
retryCount	Int32	The number of times the task has been retried by the Batch service. The task is retried if it exits with a nonzero exit code, up to the specified MaxTaskRetryCount