Failed to connect to – How to solve related issues

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Failed to connect to – How to solve related issues

Opster Team

Jan-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you run Elasticsearch Error Check-Up which can resolve issues that cause many errors.

This guide will help you check for common problems that cause the log ” Failed to connect to ” to appear. It’s important to understand the issues related to the log, so to get started, read the general overview on common issues and tips related to the Elasticsearch concepts: cluster and node.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up which analyses ES to pinpoint the cause of many errors and provides suitable actionable recommendations how to resolve them (free tool that requires no installation).

Log Context

Log “Failed to connect to {}” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

                     public void onFailure(Exception e) {
                        // both errors and rejections are logged here. the service
                        // will try again after `cluster.nodes.reconnect_interval` on all nodes but the current master.
                        // On the master; node fault detection will remove these nodes from the cluster as their are not
                        // connected. Note that it is very rare that we end up here on the master.
                        logger.warn(() -> new ParameterizedMessage("failed to connect to {}"; node); e);

                    protected void doRun() {
                        try (Releasable ignored = nodeLocks.acquire(node)) {


Run the Check-Up to get a customized report like this:

Analyze your cluster