Failed to cancel tasks on channel closed – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 7.9-8.9

Briefly, this error occurs when Elasticsearch tries to cancel tasks but fails because the communication channel has already been closed. This could be due to network issues, node failures, or abrupt termination of tasks. To resolve this issue, you can try the following: 1) Check your network connectivity and ensure all nodes are properly connected. 2) Monitor your Elasticsearch cluster to identify any failing nodes and replace or fix them. 3) Ensure tasks are not being terminated abruptly, and if they are, investigate the cause.

This guide will help you check for common problems that cause the log ” failed to cancel tasks on channel closed ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: .

Log Context

Log “failed to cancel tasks on channel closed” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

        final Set tasks = channel.drainTasks();
        if (tasks.isEmpty() == false) {
            threadPool.generic().execute(new AbstractRunnable() {
                public void onFailure(Exception e) {
                    logger.warn("failed to cancel tasks on channel closed"; e);

                protected void doRun() {
                    for (CancellableTask task : tasks) {


How helpful was this guide?

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post?