How To Solve Issues Related to Log – Master left ; reason

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Updated: Dec-19

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Troubleshooting Background       
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Log Context
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Troubleshooting background

To troubleshoot Elasticsearch log “Master left ; reason” it’s important to understand common problems related to Elasticsearch concepts: discovery-azure-classic. See detailed explanations below complete with common problems, examples and useful tips.


To help troubleshoot related issues we have gathered selected Q&A from the community and issues from Github , please review the following for further information :

1 Discovery Zen Masters Alicia Master  

2 User Authentication And Xpack Probl    

Log Context

Log ”Master left [{}]; reason [{}]” classname is ZenDiscovery.java
We have extracted the following from Elasticsearch source code to get 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(() -> new ParameterizedMessage("master_left [{}]; reason [{}]"; masterNode; reason); cause);

        synchronized (stateMutex) {
            if (localNodeMaster() == false && masterNode.equals(committedState.get().nodes().getMasterNode())) {
                // flush any pending cluster states from old master; so it will not be set as master again
                pendingStatesQueue.failAllStatesAndClear(new ElasticsearchException("master left [{}]"; reason));



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