This node is a fully-formed single-node cluster

Elastic Stack Elasticsearch
1

Hey all

I’m trying to set up a multi node cluster but this node was a single node cluster originally.

I’ve deleted the /var/lib/elasticsearch/* folder which should be the data folder on Ubuntu 24.04 but still getting the same message, this host is es1

network.host: ["localhost","192.168.131.171"]
node.roles: [ master, data, ingest ]
discovery.seed_hosts: ["192.168.131.171"]
discovery.type: multi-node
cluster.initial_master_nodes: ["es1"]

I want to start this cluster with this server as master, then move on to setting up the other nodes.

[2025-08-08T07:56:22,343][WARN ][o.e.c.c.Coordinator      ] [es1] This node is a fully-formed single-node cluster with cluster UUID [uy6ufiEQT5SyAvVjlK6yXQ], but it is configured as if to discover other nodes and form a multi-node cluster via the [discovery.seed_hosts=[192.168.131.171]] setting. Fully-formed clusters do not attempt to discover other nodes, and nodes with different cluster UUIDs cannot belong to the same cluster. The cluster UUID persists across restarts and can only be changed by deleting the contents of the node's data path(s). Remove the discovery configuration to suppress this message. See [https://www.elastic.co/docs/deploy-manage/distributed-architecture/discovery-cluster-formation/modules-discovery-bootstrap-cluster?version=9.1#modules-discovery-bootstrap-cluster-joining] for more information.

I also tried running while elasticsearch is stopped but didn’t change anything

./elasticsearch-node unsafe-bootstrap

Thanks

2

You can move on to the other nodes now. Elasticsearch is complaining because you’ve set discovery.seed_hosts but there are no other nodes to discover, which is usually a mistake. As the message says: Remove the discovery configuration to suppress this message. Or you could just ignore it.

3

Thanks DavidTurner

I’ve only formed single node clusters before

The authentication kept failing once I made the changes to the config, What fixed it was I had to re-run

/usr/share/elasticsearch/bin/elasticsearch-setup-passwords interactive