Failed to notify listeners – How to solve this OpenSearch error

Opster Team

Aug-23, Version: 1-2.9

Before you dig into reading this guide, have you tried asking OpsGPT what this log means? You’ll receive a customized analysis of your log.

Try OpsGPT now for step-by-step guidance and tailored insights into your OpenSearch operation.

Briefly, this error occurs when OpenSearch fails to alert its listeners about a particular event or change in the system. This could be due to a network issue, a bug in the system, or an overloaded server. To resolve this issue, you can try restarting the OpenSearch service, checking for any bugs in the system, or reducing the load on the server by optimizing your queries or increasing the server capacity. Additionally, ensure that your network connection is stable and reliable.

For a complete solution to your to your search operation, try for free AutoOps for Elasticsearch & OpenSearch . With AutoOps and Opster’s proactive support, you don’t have to worry about your search operation – we take charge of it. Get improved performance & stability with less hardware.

This guide will help you check for common problems that cause the log ” Failed to notify listeners ” to appear. To understand the issues related to this log, read the explanation below about the following OpenSearch concepts: listeners.

Log Context

Log “Failed to notify listeners” classname is
We extracted the following from OpenSearch source code for those seeking an in-depth context :

        if (listeners != null) {
            try {
                ActionListener.onFailure(listeners; failure);
            } catch (Exception ex) {
                assert false : new AssertionError(ex);
                logger.warn("Failed to notify listeners"; ex);

    private static  void completeListenersIgnoringException(@Nullable List> listeners; T result) {


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?

Get expert answers on Elasticsearch/OpenSearch