gr_setup80.txt

# To setup a 2x node Group Replication env:
#
# https://scriptingmysql.wordpress.com/2019/03/28/mysql-8-0-group-replication-three-server-installation/

# Add all servers to be included in the group to your /etc/hosts, on all servers:

vi /etc/hosts
10.0.0.41 olslave01 olslave01.sub09181354590.keithvcn.oraclevcn.com
10.0.0.42 olslave02 olslave02.sub09181354590.keithvcn.oraclevcn.com

sudo yum install -y mysql-*8.0.20*rpm
sudo systemctl start mysqld.service
sudo systemctl enable mysqld.service
sudo grep 'A temporary password is generated for root@localhost' /var/log/mysqld.log |tail -1
mysql -uroot -p

SET sql_log_bin = OFF;
alter user 'root'@'localhost' identified by 'Oracle20!8';
create user 'ic'@'%' identified by 'Oracle20!8';
grant all on <em>.</em> to 'ic'@'%' with grant option;
flush privileges;
SET sql_log_bin = ON;


# In node 1:

vi /etc/my.cnf
 GR setup
server-id                       =11
log-bin                         =mysql-bin
gtid-mode                       =ON
enforce-gtid-consistency        =TRUE
log_slave_updates               =ON
binlog_checksum                 =NONE
master_info_repository          =TABLE
relay_log_info_repository       =TABLE
transaction_write_set_extraction=XXHASH64

plugin_load_add                 ="group_replication.so"
group_replication               = FORCE_PLUS_PERMANENT
group_replication_bootstrap_group = OFF
  group_replication_start_on_boot = ON
group_replication_group_name    = 8E2F4761-C55C-422F-8684-D086F6A1DB0E
group_replication_local_address = '10.0.0.41:33061'
 Adjust the following according to IP's and numbers of hosts in group:
group_replication_group_seeds = '10.0.0.41:33061,10.0.0.42:33061'

# On 2nd node:
server-id                       =22
log-bin                         =mysql-bin
gtid-mode                       =ON
enforce-gtid-consistency        =TRUE
log_slave_updates               =ON
binlog_checksum                 =NONE
master_info_repository          =TABLE
relay_log_info_repository       =TABLE
transaction_write_set_extraction=XXHASH64

plugin_load_add                 ="group_replication.so"
group_replication               = FORCE_PLUS_PERMANENT
group_replication_bootstrap_group = OFF
 group_replication_start_on_boot = ON
group_replication_group_name    = 8E2F4761-C55C-422F-8684-D086F6A1DB0E
group_replication_local_address = '10.0.0.42:33061'
 Adjust the following according to IP's and numbers of hosts in group:
group_replication_group_seeds = '10.0.0.41:33061,10.0.0.42:33061'


# Stop (if started) and start the servers again:
systemctl start mysqld

# Check the config for each server
mysql -uroot

SELECT * FROM performance_schema.replication_group_members;
SELECT * FROM performance_schema.replication_group_members\G

# Maybe you need to change the UUID for a server (if for example it's been cloned):
cat /usr/local/mysql/data/auto.cnf
# By removing this file from the o.s. and rebooting the instance, a new unique file will be created.


# Check master status on the first server:
SHOW MASTER STATUS\G

# Check binlog events too:
SHOW BINLOG EVENTS in 'mysql-bin.000001'\G

# Check server2 status:
SELECT * FROM performance_schema.replication_group_members;

# Now check that the GR plugin has been installed ok on all servers:
select * from information_schema.plugins where PLUGIN_NAME = 'group_replication'\G

# I have previously created a user called 'ic@%' with 'grant all on *.*' for my testing, but a user like the following can be created.
# Be aware that we need to avoid sending these commands to the binlogs, hence sql_log_bin=0 as thi would cause errors on the slaves when replication starts:

SET SQL_LOG_BIN=0;
CREATE USER rpl_user@'%' IDENTIFIED BY 'R3plic4tion!';
GRANT REPLICATION SLAVE ON *.* TO rpl_user@'%';
FLUSH PRIVILEGES;
SET SQL_LOG_BIN=1;

# Now to create the recovery replication channel on all servers (although this is for single primary setup, the master could fail and then come back as a Read-Only slave, so we need to set this up):
#CHANGE MASTER TO MASTER_USER='rpl_user', MASTER_PASSWORD='R3plic4tion!' FOR CHANNEL 'group_replication_recovery';
CHANGE MASTER TO MASTER_USER='ic', MASTER_PASSWORD='Oracle20!8' FOR CHANNEL 'group_replication_recovery';

#
# On Server 1:

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

# On Server 2:
START GROUP_REPLICATION;

Check all the servers super_read_only mode:
select @@super_read_only;

SELECT * FROM performance_schema.replication_group_members;


###########
# Now we could convert the GR setup to an InnoDB Cluster setup using the MySQL Shell functionality "db.createCluster(... adoptFromGR)":
# https://dev.mysql.com/doc/refman/8.0/en/mysql-innodb-cluster-from-group-replication.html