Failed to send join request to master reason – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-7.15

Briefly, this error occurs when a node in Elasticsearch cluster fails to join the cluster because it cannot communicate with the master node. This could be due to network issues, incorrect configuration, or the master node being overwhelmed. To resolve this, ensure that all nodes have correct network configurations and can reach each other. Check the master node’s health and load, and consider adding more nodes or increasing resources if it’s overloaded. Also, verify your cluster settings, particularly discovery and cluster initial master nodes settings.

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

Log Context

Log “failed to send join request to master [{}]; reason [{}]” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

                } else {
                    if (logger.isTraceEnabled()) {
                        logger.trace(() -> new ParameterizedMessage("failed to send join request to master [{}]"; masterNode); e);
                    } else {
              "failed to send join request to master [{}]; reason [{}]"; masterNode;
                    return false;


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