Each API Gateway cluster node consists of an API Gateway Data Store instance. For cluster configuration, the API Gateway Data Store instances should also be clustered using Elasticsearch clustering properties, by modifying the SAG_root/InternalDataStore/config/elasticsearch.yml file on each 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 will auto-bootstrap itself into a new cluster. You cannot change the configuration after bootstrap and thus, Elasticsearch will 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/7.7/index.html.