docker-compose + mysql8.x 主从数据库配置

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;