MySQL 9.1 Release Notes
        
        It is first necessary to ensure that the Group Replication
        plugin is installed on server s1. If you used
        plugin_load_add='group_replication.so' in the
        option file then the Group Replication plugin is already
        installed, and you can proceed to the next step. Otherwise, you
        must install the plugin manually; to do this, connect to the
        server using the mysql client, and issue the
        SQL statement shown here:
      
mysql> INSTALL PLUGIN group_replication SONAME 'group_replication.so';
        To check that the plugin was installed successfully, issue
        SHOW PLUGINS; and check the output. It should
        show something like this:
      
mysql> SHOW PLUGINS;
+----------------------------+----------+--------------------+----------------------+-------------+
| Name                       | Status   | Type               | Library              | License     |
+----------------------------+----------+--------------------+----------------------+-------------+
| binlog                     | ACTIVE   | STORAGE ENGINE     | NULL                 | PROPRIETARY |
(...)
| group_replication          | ACTIVE   | GROUP REPLICATION  | group_replication.so | PROPRIETARY |
+----------------------------+----------+--------------------+----------------------+-------------+