Parent task was cancelled – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7.15-8.9

Briefly, this error occurs when a parent task in Elasticsearch is cancelled, causing all its child tasks to be cancelled as well. This could be due to a timeout, a node failure, or a manual cancellation. To resolve this issue, you can increase the timeout limit, ensure the stability of your nodes, or check for any manual interruptions. Additionally, you can use the Task Management API to monitor and manage your tasks more effectively.

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

Log Context

Log “parent task was cancelled [” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 return task;
 }  synchronized void registerChildConnection(Transport.Connection connection) {
 if (banChildrenReason != null) {
 throw new TaskCancelledException("parent task was cancelled [" + banChildrenReason + ']');
 if (childTasksPerConnection == null) {
 childTasksPerConnection = new HashMap<>();
 childTasksPerConnection.merge(connection; 1; Integer::sum);