Note, that http basic auth does work as expected for the out of the box creds:
16:22:47 es-master:~/opensearch$ curl -k -u admin:admin https://localhost:9200/
{
"name" : "opensearch-node1",
"cluster_name" : "opensearch-cluster",
"cluster_uuid" : "jY8qm053R6-Gh95YZXK2Mg",
"version" : {
"distribution" : "opensearch",
"number" : "1.3.2",
"build_type" : "tar",
"build_hash" : "6febcf7b53ff189de767e460e905e9e5aeecc8cb",
"build_date" : "2022-05-04T03:58:48.328641Z",
"build_snapshot" : false,
"lucene_version" : "8.10.1",
"minimum_wire_compatibility_version" : "6.8.0",
"minimum_index_compatibility_version" : "6.0.0-beta1"
},
"tagline" : "The OpenSearch Project: https://opensearch.org/"
}
And deliberately using the wrong password gives me the expected Unauthorized:
$ curl -k -u dadmin:admin https://localhost:9200/
Unauthorized