No longer master while failing shard – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-8

Briefly, this error occurs when a node that was previously the master is no longer the master, and it tries to fail a shard. This could be due to network issues, heavy load, or a configuration problem causing a new master to be elected. To resolve this, you can check the cluster health and logs to identify any network or load issues. If it’s a configuration issue, ensure that the discovery.zen.minimum_master_nodes setting is correctly configured. Also, consider increasing the timeout settings if the cluster is under heavy load.

This guide will help you check for common problems that cause the log ” {} no longer master while failing shard [{}] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: cluster, master, shard.

Log Context

Log “{} no longer master while failing shard [{}]” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :


                    public void onNoLongerMaster(String source) {
                        logger.error("{} no longer master while failing shard [{}]"; request.shardId; request);
                        try {
                            channel.sendResponse(new NotMasterException(source));
                        } catch (Exception channelException) {
                                () -> new ParameterizedMessage(