Log Engine failed; but cant find index shard. failure reason: – How To Solve Related Issues

Log Engine failed; but cant find index shard. failure reason: – 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 “Engine failed; but cant find index shard. failure reason:” 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, indices.

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”[{}][{}] engine failed; but can’t find index shard. failure reason: [{}]” classname is IndicesClusterStateService.java
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

                 if (indexShard != null) {
                    shardRouting = indexShard.routingEntry();
            if (shardRouting == null) {
                logger.warn("[{}][{}] engine failed; but can't find index shard. failure reason: [{}]"; failure;
                        shardId.index().name(); shardId.id(); reason);
            final ShardRouting fShardRouting = shardRouting;
            threadPool.generic().execute(new Runnable() {


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 Snapshot Failed With Partial State  

Failed To Send Ping To Node After O  


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