Task cancelled before it started – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7.8-7.14

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 system overload, slow processing speed, or an abrupt shutdown. To resolve this issue, you can try to reduce the load on your system, increase the processing power, or ensure that tasks are not being prematurely terminated. Additionally, check your task management settings to ensure tasks have enough time to start before they are cancelled.

This guide will help you check for common problems that cause the log ” Task cancelled before it started: ” 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 it started:” class name is TaskManager.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 if (task.getParentTaskId().isSet() && bannedParents.isEmpty() == false) {
 final Ban ban = bannedParents.get(task.getParentTaskId());
 if (ban != null) {
 try {
 throw new TaskCancelledException("Task cancelled before it started: " + ban.reason);
 } finally {
 // let's clean up the registration


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