Master-left ; reason ES Log v2.3 – How to solve related issues

Master-left ; reason ES Log v2.3 – How to solve related issues

Opster Team

Feb-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 ” Master-left ; reason ES Log v2.3 ” 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: discovery.

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 “master_left [{}]; reason [{}]” classname is ZenDiscovery.java
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

         if (localNodeMaster()) {
            // we might get this on both a master telling us shutting down; and then the disconnect failure
            return;
        }

        logger.info("master_left [{}]; reason [{}]"; masterNode; reason);

        clusterService.submitStateUpdateTask("zen-disco-master_failed (" + masterNode + ")"; new ClusterStateUpdateTask(Priority.IMMEDIATE) {
            
Override
            public boolean runOnlyOnMaster() {
                return false;



 

Run the Check-Up to get customized recommendations like this:

checklist Run Check-Up

error

Heavy merges detected in specific nodes

error-img

Description

A large number of small shards can slow down searches and cause cluster instability. Some indices have shards that are too small…

error-img

Recommendations Based on your specific ES deployment you should…

Based on your specific ES deployment you should…

1

X-PUT curl -H [a customized code snippet to resolve the issue]

 

 

 

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