Unexpected error while pinging – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-7.17

Briefly, this error occurs when Elasticsearch nodes are unable to communicate with each other due to network issues, incorrect configuration, or the cluster is overloaded. To resolve this, ensure that the network is stable and all nodes are reachable. Check the Elasticsearch configuration for any errors, particularly in the network settings. Also, monitor the cluster’s health and performance. If it’s overloaded, consider adding more nodes or increasing resources. Lastly, ensure that the Elasticsearch version is up-to-date and doesn’t contain any known bugs that could cause this issue.

This guide will help you check for common problems that cause the log ” unexpected error while pinging ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: discovery.

Log Context

Log “unexpected error while pinging” classname is UnicastZenPing.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

        activePingingRounds.put(pingingRound.id(); pingingRound);
        final AbstractRunnable pingSender = new AbstractRunnable() {
            public void onFailure(Exception e) {
                if (e instanceof AlreadyClosedException == false) {
                    logger.warn("unexpected error while pinging"; e);

            protected void doRun() throws Exception {


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