When running embedded in API Gateway, the API Data store instances have to be clustered by modifying the SAG_root/InternalDataStore/config/elasticsearch.yml file within each API Gateway instance. You must provide the cluster configurations in the elasticsearch.yml file in the SAG_root/InternalDataStore/config/ folder before starting the Elasticsearch for the very first time. When you start Elasticsearch, the node auto-bootstraps itself into a new cluster. You cannot change the configuration after bootstrap and thus, Elasticsearch does not merge separate clusters together after they have formed, even if you subsequently try and configure all the nodes into a single cluster. For more information, see https://www.elastic.co/guide/en/elasticsearch/reference/7.13/index.html.