Starting the MGR

Log in to the three MySQL databases on the K8s primary node respectively, and start the MGR.

1. Start the primary database of the MGR (mysql-1 is used as the primary database in this document).

   Log in to the MySQL database by running the following command:

   1	kubectl exec -it <pod_name> -n <spaces_name> -- mysql -uroot -p

   Log in to the mysql-1 database.

   1	kubectl exec -it mysql-1 -n ns-mysql-test -- mysql -uroot -p

   Execute the following statements in mysql-1 to start the MGR:

   SET GLOBAL group_replication_bootstrap_group=ON;
   START GROUP_REPLICATION;
   SET GLOBAL group_replication_bootstrap_group=OFF;

   

   In MySQL 8.0.21 or later, the START GROUP_REPLICATION; command is replaced with START GROUP_REPLICATION USER='rpl_user', PASSWORD='123456';.

2. Start the secondary databases of the MGR. In this document, mysql-2 and mysql-3 are used as secondary databases.

   Log in to the MySQL database by running the following command:

   1	kubectl exec -it <pod_name> -n <spaces_name> --mysql -uroot -p

   Log in to the mysql-2 and mysql-3 databases, respectively.

   1 2	kubectl exec -it mysql-2 -n ns-mysql-test --mysql -uroot -p kubectl exec -it mysql-3 -n ns-mysql-test --mysql -uroot -p

   Execute the following statements in mysql-2 and mysql-3 to start the MGR, respectively:

   START GROUP_REPLICATION;

   View the information about group members. You can view any member in the MGR group.

   SELECT * FROM performance_schema.replication_group_members;

   +---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
   | CHANNEL_NAME              | MEMBER_ID                            | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
   +---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
   | group_replication_applier | e44f902b-bf50-11ea-89d7-000000536bb6 | mysql-1     |        3306 | ONLINE       | PRIMARY     | 8.0.19         |
   | group_replication_applier | e51ea27b-bf50-11ea-b256-000000536bb7 | mysql-2     |        3306 | ONLINE       | SECONDARY   | 8.0.19         |
   | group_replication_applier | e5b471d9-bf50-11ea-8639-000000536bb8 | mysql-3     |        3306 | ONLINE       | SECONDARY   | 8.0.19         |
   +---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
   3 rows in set (0.01 sec)