Log Cant send shard failed for ; no master known. – How To Solve Related Issues

Log Cant send shard failed for ; no master known. – How To Solve Related Issues

Opster Team

Feb-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you try running the Elasticsearch Error Check-Up  which can resolve issues causing many log errors (free and no installation required)


This guide will help you check for common problems that cause the log “Cant send shard failed for ; no master known.” 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, shard.

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 discover the cause of many errors and provides suitable actionable recommendations. 

Log Context

Log”can’t send shard failed for {}; no master known.” classname is ShardStateAction.java
We extracted the following from Elasticsearch source code for those seeking an in-depth context :


    public void shardFailed(final ShardRouting shardRouting; final String indexUUID; final String message; 
Nullable final Throwable failure) {
        DiscoveryNode masterNode = clusterService.state().nodes().masterNode();
        if (masterNode == null) {
            logger.warn("can't send shard failed for {}; no master known."; shardRouting);
        innerShardFailed(shardRouting; indexUUID; masterNode; message; failure);


Related issues to this log

We have gathered selected Q&A from the community and issues from Github, that can help fix related issues please review the following for further information :

1 Github Issue Number 12661  

Github Issue Number 23199  


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