Index shard was not set – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch is unable to locate the shard for a specific index. This could be due to a misconfiguration, a failed shard, or a missing index. To resolve this issue, you can try the following: 1) Check your Elasticsearch configuration for any errors. 2) Verify the status of your shards using the _cat/shards API. If any shards are in a failed state, you may need to reroute them. 3) Ensure the index exists. If not, you may need to recreate it. Always remember to back up your data to prevent loss.

This guide will help you check for common problems that cause the log ” index shard was not set ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: shard, index.

Log Context

Log “index shard was not set” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 if (index == null) {
 throw new ElasticsearchParseException("index name was not set");
 if (intShardId == null) {
 throw new ElasticsearchParseException("index shard was not set");
 }  ShardId shardId = new ShardId(index; indexUuid != null ? indexUuid : IndexMetadata.INDEX_UUID_NA_VALUE; intShardId);  RestStatus restStatus;