How to avoid warning when starting with discovery.type set to single node

Elastic Stack Elasticsearch
1

Hello;

I have upgraded a single-node Elasticsearch from version 7.17 to 8.7. When the node starts up it logs this warning:

[WARN ][o.e.c.c.ClusterBootstrapService] [elasticsearch] this node is locked into cluster UUID [H6ToZxhPRAerFe-iPlqE8A] but [cluster.initial_master_nodes] is set to [elasticsearch]; remove this setting to avoid possible data loss caused by subsequent cluster bootstrap attempts; for further information see https://www.elastic.co/guide/en/elasticsearch/reference/8.7/important-settings.html#initial_master_nodes`

I have removed the cluster.initial_master_nodes property and added discovery.type: single-node, but the warning persists.

Next, I have looked at the various scripts delivered with Elasticsearch in the bin-direktory, but I do not find any suitable to remove the cluster_uuid from the cluster state.

{
  "name" : "elasticsearch",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "H6ToZxhPRAerFe-iPlqE8A",
  "version" : {
    "number" : "8.7.1",

How do I get rid of the warning?

Best regards
Flemming

2

The warning indicates that you have not removed cluster.initial_master_nodes. Maybe you adjusted the wrong elasticsearch.yml file, or maybe it is being passed in on the command line. In any case, that's what you must do to fix the warning.

3

Thanks @DavidTurner Elastic runs in Docker so maybe I was fooled and not editing the right elasticsearch.yml file on the fly.

I make a new image and update the post with the result-

4

I believe there is a bug in de code that logs the warning (elasticsearch/server/src/main/java/org/elasticsearch/cluster/coordination/ClusterBootstrapService.java at main · elastic/elasticsearch · GitHub). The assumption is made that bootstrapRequirements is filled with the cluster.initial_master_nodes setting, but in fact it is filled with the node.name setting in case of single node discovery

5

Ohh right. Yes that looks like a bug indeed. Thanks @PeterNagel!

I opened Cluster bootstrap warning incorrectly emitted for `discovery.type: single-node` · Issue #96874 · elastic/elasticsearch · GitHub.