Cluster UUID – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 7-8.2

Briefly, this error occurs when Elasticsearch cannot identify the cluster due to a missing or mismatched UUID (Universally Unique Identifier). This could be due to a misconfiguration or data corruption. To resolve this issue, you can try the following: 1) Check the cluster settings and ensure the UUID matches across all nodes. 2) If the UUID is missing, you may need to restart the cluster to generate a new one. 3) If data corruption is suspected, consider restoring from a backup. Always ensure to maintain regular backups to prevent data loss.

we recommend you run the Elasticsearch Error Check-Up to resolve this issue and many others.

This guide will explain how to resolve this log and expand on how clusters function in Elasticsearch.


When an Elasticsearch cluster spins up for the first time, Elasticsearch generates a unique identifier for it, known as the cluster UUID.

What does this message mean?

This log message is an INFO message, indicating the unique identification string of the cluster when the cluster starts up.

Every node keeps track of the cluster UUID it is part of and will not join another cluster with a different UUID.

You may also check this by going to `<your-es-host>:9200` in your browser and looking for `cluster_uuid` in the response.

   "name": "Opster",
   "cluster_name": "es_8",
   "cluster_uuid": "niwmztQkSpO9ODZGmHuQ",
   "version": {
       "number": "8.0.0",
       "build_flavor": "default",
       "build_type": "tar",
       "build_hash": "4e6e4eab2297e949ec994e688dad46290d018022",
       "build_date": "2022-01-06T23:43:02.825887787Z",
       "build_snapshot": false,
       "lucene_version": "8.10.1",
       "minimum_wire_compatibility_version": "6.8.0",
       "minimum_index_compatibility_version": "6.0.0-beta1"
   "tagline": "You Know, for Search"

How to reproduce this log

Run the following command to start Elasticsearch from the command line:


The following log line will appear in the logs once Elasticsearch has been started.

[2022-02-12T13:12:07,696][INFO ][o.e.c.c.Coordinator      ] [ubuntu] cluster UUID [0fnOxVu8SeCi74UoU9bTOg]

Log Context

Log “cluster UUID [{}]” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

            coordinationState.set(new CoordinationState(getLocalNode(); persistedState; electionStrategy));
            final ClusterState lastAcceptedState = coordinationState.get().getLastAcceptedState();
            if (lastAcceptedState.metadata().clusterUUIDCommitted()) {
      "cluster UUID [{}]"; lastAcceptedState.metadata().clusterUUID());
            final VotingConfiguration votingConfiguration = lastAcceptedState.getLastCommittedConfiguration();
            if (singleNodeDiscovery
                && votingConfiguration.isEmpty() == false
                && votingConfiguration.hasQuorum(Collections.singleton(getLocalNode().getId())) == false) {


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