0.准备 （略过docker的安装与镜像拉取）

docker / docker-compose 安装

拉取 mysql 8.x

1. master和slave的mysql配置

master:

[mysqld]
server-id=11118
log-bin=mysql-bin

slave:

[mysqld]
log-bin=mysql-bin
server-id=11105

注： 两个 server-id 一定要 不一样

2. docker-compose 文件 设置

version: "3"

services:
db:
image: mysql
ports:
- "3307:3306"
volumes:
- ./dockerMysql/master/db:/var/lib/mysql
- ./dockerMysql/master/cnf:/etc/mysql/conf.d
environment:
- MYSQL_DATABASE=siemens
- MYSQL_ROOT_PASSWORD=123456
networks:
mynet-tier::
ipv4_address: 172.16.238.2
slave:
image: mysql
ports:
- "3308:3306"
volumes:
- ./dockerMysql/slave/db1:/var/lib/mysql
- ./dockerMysql/slave/cnf:/etc/mysql/conf.d
environment:
- MYSQL_DATABASE=siemens
- MYSQL_ROOT_PASSWORD=123456
links:
- db
networks:
- mynet-tier:

networks:
mynet-tier:
ipam:
# driver: overlay
config:
- subnet: "172.16.238.0/24"

注： 这里专门配置了子网和固定IP（static IP），方便后面重启数据库后，以脚本的形式自动重新设置slave的参数，没有此需求也可不必。

3. mysql 主从配置

3.1 设置 master

进入 docker
docker exec -it bin_db_1 bash

进入mysql
mysql -u root -pxxx

创建用户并授权（mysql 8.x 与 5.x 有区别，这里是8.x方式），这里使用root用户来做著丛，推荐创建专门用户来做
mysql> CREATE USER 'root'@'%' IDENTIFIED BY 'xxx';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION;
mysql> FLUSH PRIVILEGES;
mysql> show master status\G;

*************************** 1. row ***************************
File: mysql-bin.000001
Position: 236480
Binlog_Do_DB:
Binlog_Ignore_DB:
Executed_Gtid_Set:
1 row in set (0.00 sec)

注： 这里的 File 和 Position 信息很重要， 后面slave设置时会用到。

3.2 设置 slave

进入docker
docker exec -it bin_slave_1 bash

进入mysql
mysql -u root -pxxx

停止、重置 slave
mysql> stop slave;
mysql> reset slave;

设置主库，启用 slave
mysql> change master to master_host='172.18.0.3',master_user='root',master_password='xxx',master_port=3306,master_log_file='mysql-bin.000001',master_log_pos=236480;
mysql> start slave;

查看slave，确保 Slave_IO_Running: Yes 和 Slave_SQL_Running: Yes
mysql> show slave status\G;

*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 172.18.0.3
Master_User: root
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 236480
Relay_Log_File: cc9a6ddfeacd-relay-bin.000002
Relay_Log_Pos: 322
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 236480
Relay_Log_Space: 537
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 11108
Master_UUID: f949b20a-7a18-11ed-80df-0242ac120003
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
Master_public_key_path:
Get_master_public_key: 0
1 row in set (0.00 sec)

注： Slave_IO_Running 和 Slave_SQL_Running 的值都为Yes 表示slave启动成功。

补充1.  数据库重启后需更新slave的配置

由于一些原因导致docker容器停止，重新启动docker后，slave 会无法同步主库。需要重新设置

进入docker
docker exec -it bin_slave_1 bash

进入mysql
mysql -u root -pxxx

停止、重置 slave
mysql> stop slave;
mysql> reset slave;

设置主库，启用 slave
mysql> change master to master_host='172.18.0.x',master_user='root',master_password='xxx',master_port=3306,master_log_file='mysql-bin.00000x',master_log_pos=xxx;
mysql> start slave;

注：先进入slave的mysql，停止、重置。最后重新设定slave（高亮红色的部分）

补充2. 常见问题

1）主从库uuid和server_id重复导致错误;
Fatal error: The slave I/O thread stops because master and slave have equal MySQL server ids; these ids must be different for replication to work (or the --replicate-same-server-id option must be used on slave but this does not always make sense; please check the manual before using it).

解决方案：

在mysql中输入以下命令，查看主从库是否重复，确保两者不同；

show variables like '%server_uuid%';
show variables like '%server_id%';

server_id：

1.可以在my.cnf中修改，但重启后可能依然不生效；

2.用“SET GLOBAL server_id=;”解决，但此命令会在mysql服务重启后丢失。

在mysql中的auto.cnf中修改；

待uu_id和server_id修改完后重启容器。

2）docker-compose down / up MySQL容器IP变化

重启 docker-compose 后，需要根据MySQL master 的 IP 来设置

mysql> change master to master_host='newIP',master_user='root',master_password='xxx',master_port=3306,master_log_file='mysql-bin.00000x',master_log_pos=xxx;