= GROUP Replicate master-master =
All node can write (primary)

On nodedb1, just start docker with, pls download mysql-8.0.11 source 
{{{
docker run -d --name=nodedb1 --net=group1 --hostname=nodedb1 -p 3306:3306 \
    -v $PWD/mysql-8.0.11/d1:/var/lib/mysql \
    -e MYSQL_ROOT_PASSWORD=mypass   mysql/mysql-server:8.0.11 \
    --server-id=1  \
    --log-bin='mysql-bin-1.log' \
    --enforce-gtid-consistency='ON' \
    --log-slave-updates='ON'   \
    --gtid-mode='ON' \
    --transaction-write-set-extraction='XXHASH64' \
    --binlog-checksum='NONE' \
    --master-info-repository='TABLE' \
    --relay-log-info-repository='TABLE' \
    --plugin-load='group_replication.so' \
    --relay-log-recovery='ON' \
    --group-replication-start-on-boot='OFF' \
    --group-replication-group-name='aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee' \
    --group-replication-local-address="nodedb1:33061" \
    --group-replication-group-seeds='nodedb1:33061,nodedb2:33061,nodedb3:33061' \
    --loose-group-replication-single-primary-mode='OFF' \
    --loose-group-replication-enforce-update-everywhere-checks='ON'
}}}
Then start mysql with '''docker exec -it nodedb1 -uroot -pmypass'''
{{{
mysql> create user 'repl'@'%';
       GRANT ALL  ON * . * TO repl@'%';
       flush privileges;
       SET @@GLOBAL.group_replication_group_name='aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee';
       SET @@GLOBAL.group_replication_local_address='nodedb1:33061';
       SET @@GLOBAL.group_replication_group_seeds='nodedb1:33061,nodedb2:33061,nodedb3:33061';
       SET @@GLOBAL.group_replication_bootstrap_group=1;
       change master to master_user='repl' for channel 'group_replication_recovery';
       START GROUP_REPLICATION;
       SET @@GLOBAL.group_replication_bootstrap_group=0;
       SELECT * FROM performance_schema.replication_group_members;
}}}


On nodedb2, start docker same as nodedb1 but change --name=nodedb2, --hostname=nodedb2, --server-id=2, -v $PWD/mysql-8.0.11/d2:/var/lib/mysql, --group-replication-local-address="nodedb2:33061"
{{{
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;
}}}

On nodedb3
{{{
mysql> SET @@GLOBAL.group_replication_group_name='aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee';
       SET @@GLOBAL.group_replication_local_address='nodedb3:33061';
       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;
}}}