Certain operations, including configuring server (instance level) settings, or manually adding a database to an availability group, require a connection to the SQL Server Instance. Operations like sp_configure, RESTORE DATABASE, or any DDL command in a database belonging to an availability group require a connection to the SQL Server instance. By default, a big data cluster does not include an endpoint that enables a connection to the instance. You must expose this endpoint manually.
For instructions, see Connect to databases on the primary replica.