Briefly, this error occurs when Elasticsearch Machine Learning (ML) jobs are in a deleting state but no deletion task is running. This is a maintenance task that Elasticsearch performs to clean up ML jobs that are marked for deletion but haven’t been deleted yet. To resolve this issue, you can manually delete the ML jobs using the Delete Job API. Alternatively, you can restart the Elasticsearch node to refresh the system and potentially clear the deleting state of the jobs. Lastly, ensure that there are no issues with your cluster’s health that could be causing delays in task processing.
This guide will help you check for common problems that cause the log ” Successfully completed [ML] maintenance task: triggerDeleteJobsInStateDeletingWithoutDeletionTask ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin, task, delete.
Overview
A task is an Elasticsearch operation, which can be any request performed on an Elasticsearch cluster, such as a delete by query request, a search request and so on. Elasticsearch provides a dedicated Task API for the task management which includes various actions, from retrieving the status of current running tasks to canceling any long running task.
Examples
Get all currently running tasks on all nodes of the cluster
Apart from other information, the response of the below request contains task IDs of all the tasks which can be used to get detailed information about the particular task in question.
GET _tasks
Get detailed information of a particular task
Where clQFAL_VRrmnlRyPsu_p8A:1132678759 is the ID of the task in below request
GET _tasks/clQFAL_VRrmnlRyPsu_p8A:1132678759
Get all the current tasks running on particular nodes
GET _tasks?nodes=nodeId1,nodeId2
Cancel a task
Where clQFAL_VRrmnlRyPsu_p8A:1132678759 is the ID of the task in the below request
POST /_tasks/clQFAL_VRrmnlRyPsu_p8A:1132678759/_cancel?pretty
Notes
- The Task API will be most useful when you want to investigate the spike of resource utilization in the cluster or want to cancel an operation.
Overview
DELETE is an Elasticsearch API which removes a document from a specific index. This API requires an index name and _id document to delete the document.
Delete a document
DELETE /my_index/_doc/1
Notes
- A delete request throws 404 error code if the document does not already exist in the index.
- If you want to delete a set of documents that matches a query, you need to use delete by query API.
Log Context
Log “Successfully completed [ML] maintenance task: triggerDeleteJobsInStateDeletingWithoutDeletionTask” classname is MlDailyMaintenanceService.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
.filter(t -> t.v2().isAcknowledged() == false)
.map(Tuple::v1)
.map(DeleteJobAction.Request::getJobId)
.collect(toList());
if (jobIds.isEmpty()) {
logger.info("Successfully completed [ML] maintenance task: triggerDeleteJobsInStateDeletingWithoutDeletionTask");
} else {
logger.info("The following ML jobs could not be deleted: [" + String.join(";"; jobIds) + "]");
}
finalListener.onResponse(AcknowledgedResponse.TRUE);
};
