Briefly, this error occurs when Elasticsearch Machine Learning (ML) jobs are unable to start due to insufficient capacity on ML nodes. This could be due to high resource usage or limited memory. To resolve this, you can either increase the memory capacity of your existing ML nodes, add more ML nodes to your cluster, or reduce the memory requirement of your ML jobs. Also, ensure that your ML nodes are properly configured and are not experiencing any network or hardware issues.
This guide will help you check for common problems that cause the log ” Could not open job because no ML nodes with sufficient capacity were found ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin, task.
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.
Log Context
Log “Could not open job because no ML nodes with sufficient capacity were found” class name is OpenJobPersistentTasksExecutor.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :
static ElasticsearchException makeNoSuitableNodesException(Logger logger; String jobId; String explanation) {
String msg = "Could not open job because no suitable nodes were found; allocation explanation [" + explanation + "]";
logger.warn("[{}] {}"; jobId; msg);
Exception detail = new IllegalStateException(msg);
return new ElasticsearchStatusException("Could not open job because no ML nodes with sufficient capacity were found";
RestStatus.TOO_MANY_REQUESTS; detail);
} static ElasticsearchException makeAssignmentsNotAllowedException(Logger logger; String jobId) {
String msg = "Cannot open jobs because persistent task assignment is disabled by the ["
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