GROUP Replicate master-master

All node can write (primary)

On nodedb2

mysql> SET @@GLOBAL.group_replication_group_name='aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee';
       SET @@GLOBAL.group_replication_local_address='nodedb2:33061';
       SET @@GLOBAL.group_replication_group_seeds='nodedb1:33061,nodedb2:33061,nodedb3:33061';
       SET @@GLOBAL.group_replication_bootstrap_group=0;
       SET @@global.group_replication_recovery_retry_count=5;
       change master to master_user='repl' for channel 'group_replication_recovery';
       START GROUP_REPLICATION;
       SELECT * FROM performance_schema.replication_group_members;

Add user and password without authenticates with caching_sha2_plugin. Just use WITH mysql_native_password

mysql> CREATE USER 'user1'@'%' IDENTIFIED WITH mysql_native_password BY 'password';
mysql> FLUSH PRIVILEGES;