使用docker实现mysql主从同步

       本文是以最少步骤的安装,仅实现了在dockermysql的主从同步

1. 创建Docker镜像

       创建两个MySQL版本:5.7的镜像,一个容器名称为master,另一个为slaver。

docker run -d --name master -e MYSQL_ROOT_PASSWORD=root -p 3306:3306 mysql:5.7
docker run -d --link master:master  --name slaver -e MYSQL_ROOT_PASSWORD=root -p 3307:3306 mysql:5.7

       通过docker inspect命令查看容器的ip+port
       master主数据库为<master-mysql-ip> <master-mysql-port>。
       slaver从数据库<slave-mysql-ip> <slave-mysql-port> 对宿主机是3306,对于容器来说依旧是3306。

2. 主数据库配置

       修改配置主数据库master的配置文件可以通过exec进入命令,但是需要更新apt-get,然后再安装vim编辑工具,所以我才用的是docker cp命令进行修改的。

docker cp master:/etc/mysql/mysql.cnf  <host-machine-pwd>

       配置文件显示为如下内容。

[mysqld]
server-id=1
log-bin=log
binlog-ignore-db=mysql
binlog-ignore-db=information_schema
binlog-ignore-db=performance_schema
binlog-ignore-db=sys
#binlog-ignore-db设置不需要同步的库

       然后再复制回去。

docker cp <host-machine-pwd>/mysql.cnf master:/etc/mysql/

       然后连接数据库执行一下命令。

create user 'slaver'@'%' identified by 'slaver';
grant FILe on *.* to 'slaver'@'<slave-mysql-ip>' identified by 'slaver';  
grant replication slave on *.* to 'slaver'@'<slave-mysql-ip>' identified by 'slaver';
flush privileges;

       此命令表示创建一个名为slaver密码也为slaver的账户,然后授予主从复制权限给这个用户,其中<slave-mysql-ip>为slaver的host。
执行完毕后重启数据库(重启镜像),而后连接主数据库master,执行show master status。

mysql> show master status;
+------------+----------+--------------+-------------------------------------------------+-------------------+
| File       | Position | Binlog_Do_DB | Binlog_Ignore_DB                                | Executed_Gtid_Set |
+------------+----------+--------------+-------------------------------------------------+-------------------+
| log.000002 |      414 |              | mysql,information_schema,performance_schema,sys |                   |
+------------+----------+--------------+-------------------------------------------------+-------------------+
1 row in set (0.00 sec)

3. 从数据库配置

       复制文件至宿主机

docker cp slaver:/etc/mysql/mysql.cnf  <host-machine-pwd>/

       修改服务名称,注意,server-id不能和主节点重复。

[mysqld]
server-id=2
log-bin=mysql-bin
replicate-ignore-db=mysql
replicate-ignore-db=information_schema
replicate-ignore-db=performance_schema
replicate-ignore-db=sys
log-slave-updates
slave-skip-errors=all
slave-net-timeout=60
#binlog-ignore-db设置不需要同步的库

       然后再复制回去

docker cp <host-machine-pwd>/mysql.cnf slaver:/etc/mysql/

       然后重启数据库(重启镜像),连接从数据库执行 stop slave。

stop slave
change master to 
MASTER_HOST ='10.20.66.150', 
MASTER_USER ='slaver',
MASTER_PASSWORD ='slaver',
MASTER_PORT  = 3306,
MASTER_LOG_FILE ='log.000002',
MASTER_LOG_POS =414;
start slave;

       看到别人的博客在配置这里的地方都有错误,在这里我贴出官网文档, https://dev.mysql.com/doc/refman/5.7/en/change-master-to.html

       到目前为止主从同步已经搭建完成,在从库中使用show slave status \G;查看同步状态

mysql> show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 172.17.0.2
                  Master_User: slaver
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: log.000002
          Read_Master_Log_Pos: 414
               Relay_Log_File: 3a03e76858dd-relay-bin.000003
                Relay_Log_Pos: 615
        Relay_Master_Log_File: log.000002
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB:
          Replicate_Ignore_DB: mysql,information_schema,performance_schema,sys
           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: 414
              Relay_Log_Space: 1661
              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: 1
                  Master_UUID: beecd22a-ac7b-11ea-b4ba-0242ac110002
             Master_Info_File: /var/lib/mysql/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:
1 row in set (0.00 sec)

Slave_IO_Running: Yes
Slave_SQL_Running: Yes
       上方两条结果表示运行正常,如果失败,请看
Last_IO_Errno:
Last_IO_Error:
       搭建过程中遇到了一个问题就是数据库密码错误导致无法连接主库,所以还是要仔细小心
       具体的学习主从复制的配置,可以翻阅官方文档 https://dev.mysql.com/doc/refman/5.7/en/replication.html