Log Rerouting shards: – How To Solve Related Issues

Log Rerouting shards: – How To Solve Related Issues

Opster Team

Jan-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 “Rerouting shards:” 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: allocation, cluster, monitor, routing, threshold.

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”Rerouting shards: [{}]” classname is DiskThresholdMonitor.java
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

            if (reroute) {
                logger.info("rerouting shards: [{}]"; explanation);
            indicesToMarkReadOnly.removeIf(index -> state.getBlocks().indexBlocked(ClusterBlockLevel.WRITE; index));
            if (indicesToMarkReadOnly.isEmpty() == false) {


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 ElasticSearch: Unassigned Shards, how to fix? -views 203.11 K ,score 152

Rerouting Shards In Cluster  


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