Task is not found – How to solve this Elasticsearch error

Opster Team

July-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you try running the Elasticsearch Check-Up which can resolve issues that cause many errors.

This guide will help you check for common problems that cause the log ” task is not found ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: admin, node, task and cluster.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up to analyze Elasticsearch configuration and help resolve this error.

Log Context

Log “task [{}] is not found”classname  is TransportCancelTasksAction.java We extracted the following from Elasticsearch source code for those seeking an in-depth context :

} else {
 if (taskManager.getTask(request.getTaskId().getId()) != null) {
 // The task exists; but doesn't support cancellation
 throw new IllegalArgumentException("task [" + request.getTaskId() + "] doesn't support cancellation");
 } else {
 throw new ResourceNotFoundException("task [{}] is not found"; request.getTaskId());
 } else {
 for (CancellableTask task : taskManager.getCancellableTasks().values()) {
 if (request.match(task)) {


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