Operation only allowed when shard is active – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when an operation is attempted on a shard that is not active in Elasticsearch. This could be due to the shard being in the process of initialization, relocation, or recovery. To resolve this issue, you can wait for the shard to become active before retrying the operation. Alternatively, you can check the cluster health and shard status to identify any underlying issues causing the shard to be inactive. If necessary, you may need to manually reroute the shard or restart the Elasticsearch node.

This guide will help you check for common problems that cause the log ” operation only allowed when shard is active ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: shard, index.

Log Context

Log “operation only allowed when shard is active” class name is IndexShard.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 }  public void forceMerge(ForceMergeRequest forceMerge) throws IOException {
 IndexShardState state = this.state; // one time volatile read
 if (state != IndexShardState.STARTED) {
 throw new IllegalIndexShardStateException(shardId; state; "operation only allowed when shard is active");
 logger.trace("force merge with {}"; forceMerge);
 Engine engine = getEngine();
 engine.forceMerge(forceMerge.flush(); forceMerge.maxNumSegments(); forceMerge.onlyExpungeDeletes(); forceMerge.forceMergeUUID());