Task cancelled before starting – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7.15-8.9

Briefly, this error occurs when an Elasticsearch task is cancelled before it gets a chance to start. This could be due to a variety of reasons such as high load on the cluster, slow network, or a timeout setting. To resolve this issue, you can try to reduce the load on the cluster by optimizing your queries or increasing the capacity of your cluster. You could also try to improve your network speed or increase the timeout setting for your tasks.

This guide will help you check for common problems that cause the log ” task cancelled before starting [ ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: task.

Log Context

Log “task cancelled before starting [” class name is TaskManager.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 if (task.getParentTaskId().isSet()) {
 final Ban ban = bannedParents.get(task.getParentTaskId());
 if (ban != null) {
 try {
 throw new TaskCancelledException("task cancelled before starting [" + ban.reason + ']');
 } finally {
 // let's clean up the registration


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