If you’re hosted with ElasticPress.io, simply add your Subscription ID and Token into the ElasticPress settings page to secure your ElasticPress installation.

ElasticPress can be used with the Elasticsearch Shield plugin

Define the constant ES_SHIELD in your wp-config.php file with the username and password of your Elasticsearch Shield user. For example:

define( 'ES_SHIELD', 'username:password' );