Master node failed restarting discovery – How to solve this OpenSearch error

Opster Team

Aug-23, Version: 1-2

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Briefly, this error occurs when the master node in an OpenSearch cluster fails or becomes unresponsive. This could be due to network issues, resource constraints, or configuration problems. To resolve this issue, you can try the following: 1) Check the network connectivity between the nodes; 2) Ensure the master node has sufficient resources (CPU, memory, disk space); 3) Review the OpenSearch configuration for any errors; 4) Restart the master node or the entire cluster if necessary. Always ensure to have a backup of your data before performing any major operations.

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This guide will help you check for common problems that cause the log ” master node [{}] failed; restarting discovery ” to appear. To understand the issues related to this log, read the explanation below about the following OpenSearch concepts: discovery, master, node, cluster.

Log Context

Log “master node [{}] failed; restarting discovery” classname is
We extracted the following from OpenSearch source code for those seeking an in-depth context :

    private void onLeaderFailure(Exception e) {
        synchronized (mutex) {
            if (mode != Mode.CANDIDATE) {
                assert lastKnownLeader.isPresent();
       ParameterizedMessage("master node [{}] failed; restarting discovery"; lastKnownLeader.get()); e);


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