= Group Replicate =

Ref [https://dev.mysql.com/blog-archive/setting-up-mysql-group-replication-with-mysql-docker-images/ here]

We use docker swarm 3 nodes

1. pull image to 3 docker nodes 
{{{
$ docker pull mysql/mysql-server:8.0
}}}

2. Using docker-compose.yml file in atttached here and command '''docker-compose stack deploy -c docker-compose.yml db'''
{{{
$ docker-compose stack deploy -c docker-compose.yml db

Ignoring unsupported options: restart
Ignoring deprecated options:
container_name: Setting the container name is not supported.

Creating network db_mysqlgr
Creating service db_node2
Creating service db_node3
Creating service db_node1
}}}

3. Check with '''docker stack ps db'''
{{{
root@n1:/home/ubuntu/GR# docker stack ps db
ID             NAME         IMAGE                    NODE      DESIRED STATE   CURRENT STATE                ERROR     PORTS
z8tarrgj0isq   db_node1.1   mysql/mysql-server:8.0   n3        Running         Running 50 seconds ago                 
xt8vagtlz79c   db_node2.1   mysql/mysql-server:8.0   n2        Running         Running about a minute ago             
ve5o54jtwc4v   db_node3.1   mysql/mysql-server:8.0   n1        Running         Running about a minute ago          
}}}

4. On master node1, in command pls change '''node1''' to docker id ex. 26b55aaad407 which can be checked with '''docker ps''' on swarm node n3 
{{{
docker exec -it node1 mysql -uroot -pmypass \
  -e "SET @@GLOBAL.group_replication_bootstrap_group=1;" \
  -e "create user 'repl'@'%';" \
  -e "GRANT REPLICATION SLAVE ON *.* TO repl@'%';" \
  -e "flush privileges;" \
  -e "change master to master_user='repl' for channel 'group_replication_recovery';" \
  -e "START GROUP_REPLICATION;" \
  -e "SET @@GLOBAL.group_replication_bootstrap_group=0;" \
  -e "SELECT * FROM performance_schema.replication_group_members;"
}}}

5. On replicate node2, node3, pls change '''node2''' to docker id ex. ac87f41b140c which can be checked with '''docker ps''' on swarm node n1, n2
{{{
root@n1:/home/ubuntu/GR# docker exec -it ac87f41b140c mysql -uroot -pmypass \
   -e "change master to master_user='repl' for channel 'group_replication_recovery';" \
   -e "START GROUP_REPLICATION;"
}}}
We also do above command with node3 (replicate node)

6. Check all nodes status on node1 
{{{
root@n3:/home/ubuntu# docker exec -it 26 mysql -uroot -pmypass   -e "SELECT * FROM performance_schema.replication_group_members;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+----------------------------+
| CHANNEL_NAME              | MEMBER_ID                            | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION | MEMBER_COMMUNICATION_STACK |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+----------------------------+
| group_replication_applier | 852f597b-e92c-11ec-9238-02420a000b03 | node2       |        3306 | ONLINE       | SECONDARY   | 8.0.29         | XCom                       |
| group_replication_applier | 89a10b8c-e92c-11ec-9362-02420a000b06 | node3       |        3306 | ONLINE       | SECONDARY   | 8.0.29         | XCom                       |
| group_replication_applier | 8ef43b09-e92c-11ec-936c-02420a000b09 | node1       |        3306 | ONLINE       | PRIMARY     | 8.0.29         | XCom                       |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+----------------------------+
root@n3:/home/ubuntu# 
}}}