数据库中间件：CentOS7下MySQL主从Master-Slaves同步配置（一）

CentOS7下MySQL主从Master-Slaves同步配置

环境说明
Centos版本: CentOS Linux release 7.7.1908 (Core)
Linux连接工具：SecureCRT
MySQL Version: 5.7.28
主库主机地址：192.168.163.61
从库主机地址：192.168.163.62
参考文档：https://dev.mysql.com/doc/refman/5.7/en/replication.html

为什么要做主从同步

主从配置原理

配置主从同步

1.1 配置主服务器

• 修改主服务器配置文件/etc/my.cnf

#启用二进制日志记录 ：主服务器基于二进制日志文件位置的复制
log-bin=mysql-bin 
#每个服务器必须配置有唯一的服务器ID，实战中，通常配置为IP的最后一个数字
server-id=61
#指定可以主从同步的数据库，多数据库要配置多行
binlog-do-db=db_consumer
binlog-ignore-db=information_schema
binlog-ignore-db=mysql 
binlog-ignore-db=orders
binlog-ignore-db=performance_schema
binlog-ignore-db=sys

• 重启MySQL服务

[root@localhost ~]# service mysqld restart
Redirecting to /bin/systemctl restart mysqld.service

• 查看主服务器当前二进制日志名和偏移量，从数据库启动的时候，从这个点开始进行数据恢复

#查看主服务器的状态
mysql> show master status \G;
*************************** 1. row ***************************
 File: mysql-bin.000008                -------- 二进制日志名称
 Position: 154                            -------- 偏移量
 Binlog_Do_DB: db_consumer        -------- 要进行主从复制的数据库
 Binlog_Ignore_DB: information_schema,mysql,orders,performance_schema,sys -------- 不进行主从复制的数据库
 Executed_Gtid_Set:                    --------  #TODO

• 在主服务器上创建一个允许从数据库来访问的用户，并赋予权限

#创建用户
mysql>CREATE USER 'repl'@'192.168.163.62' IDENTIFIED BY 'Root2020.';
Query OK, 0 rows affected (0.02 sec)
#给用户赋予权限
mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'192.168.163.62';
Query OK, 0 rows affected (0.02 sec)
#刷新
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)

• 对主服务器的数据进行备份

第二步：从库数据库配置

• 修改从服务器配置文件/etc/my.cnf

#每个服务器必须配置有唯一的服务器ID，实战中，通常配置为IP的最后一个数字
server-id=62

• 重启MySQL服务

[root@localhost ~]# service mysqld restart
Redirecting to /bin/systemctl restart mysqld.service

• 在从服务器上设置主服务器配置信息

mysql> CHANGE MASTER TO
    -> MASTER_HOST='192.168.163.61',
    -> MASTER_USER='repl',
    -> MASTER_PASSWORD='Root2020.',
    -> MASTER_LOG_FILE='mysql-bin.000008',
    -> MASTER_LOG_POS=515;
#错误原因是：当前slave进程没有停止需要先停止
ERROR 3021 (HY000): This operation cannot be performed with a running slave io thread; run STOP SLAVE IO_THREAD FOR CHANNEL '' first.
mysql> stop slave;
Query OK, 0 rows affected (0.01 sec)

mysql> 
mysql> CHANGE MASTER TO
    -> MASTER_HOST='192.168.163.61',
    -> MASTER_USER='repl',
    -> MASTER_PASSWORD='Root2020.',
    -> MASTER_LOG_FILE='mysql-bin.000008',
    -> MASTER_LOG_POS=515;
Query OK, 0 rows affected, 2 warnings (0.02 sec)

• 启动从服务器salve进程，查看从服务器slave的进程状态

mysql> start slave;
Query OK, 0 rows affected (0.03 sec)
#   Slave_IO_Running: Yes 和 Slave_SQL_Running: Yes 状态都为YES才可以
mysql> show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: Connecting to master
                  Master_Host: 192.168.163.61
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000008
          Read_Master_Log_Pos: 515
               Relay_Log_File: localhost-relay-bin.000001
                Relay_Log_Pos: 4
        Relay_Master_Log_File: mysql-bin.000008
             Slave_IO_Running: Connecting
            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: 515
              Relay_Log_Space: 154
              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: NULL
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 2003
                Last_IO_Error: error connecting to master '[email protected]:3306' - retry-time: 60  retries: 1
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 0
                  Master_UUID: 6e8275ca-2708-11ea-b43e-000c29e7ba58
             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: 200102 10:51:31
     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)

第三步：从服务器同步主服务器上的历史数据

• 停止主数据的的更新操作，以保证数据的一致性

mysql> flush tables with read lock;
Query OK, 0 rows affected (0.02 sec)

• 备份数据库

#用mysqldump命令备份数据库，参考：https://dev.mysql.com/doc/refman/5.7/en/mysqldump.html文档
[root@localhost ~]# mysqldump -u root -p  orders > /home/backup/mysql/orders-202012.sql         
Enter password: 
[root@localhost ~]# cd /home/backup/mysql/
[root@localhost mysql]# ls
orders-202012.sql
#将备份的文件发送到从服务器
[root@localhost mysql]# scp orders-202012.sql 'root'@'192.168.163.62':/home/backup/mysql/
[email protected]'s password: 
orders-202012.sql 

• 在冲服务器上执行备份文件

[root@localhost mysql]# mysql -u root -p orders < orders-202012.sql 
Enter password: 

第四步：主库中添加数据库&表 查看从数据库是否同步显示

第五步：可能会遇到的问题

5.1 Could not find first log file name in binary log index file

• 查看从服务器上slave显示状态，查看报错信息

mysql> show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: 
                  Master_Host: 192.168.163.61
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File:  mysql-bin.000011
          Read_Master_Log_Pos: 154
               Relay_Log_File: localhost-relay-bin.000001
                Relay_Log_Pos: 4
        Relay_Master_Log_File:  mysql-bin.000011
        #这个地方显示状态是：NO
             Slave_IO_Running: No
            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: 154
              Relay_Log_Space: 154
              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: NULL
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 1236
                Last_IO_Error: Got fatal error 1236 from master when reading 
               #错误信息：不能再主服务器上找到日志文件 
                data from binary log: 'Could not find first log file name in binary log index file'
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 61
                  Master_UUID: 6e8275ca-2708-11ea-b43e-000c29e7ba58
             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: 200102 11:54:18
     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: 

• 切换到从服务器，停止slave进程

mysql> stop slave;
Query OK, 0 rows affected (0.06 sec)

• 切换到主服务器查看主服务状态

mysql> show master status;
File:mysql-bin.000012
Position: 154
Binlog_Do_DB :db_consumer,orders
Binlog_Ignore_DB :information_schema,mysql,performance_schema,sys\
1 row in set (0.00 sec)
#刷新binlog日志
mysql> flush logs;
Query OK, 0 rows affected (0.02 sec)
再次查看master状态：
mysql> show master status;
File:mysql-bin.000013
Position: 154
Binlog_Do_DB :db_consumer,orders
Binlog_Ignore_DB :information_schema,mysql,performance_schema,sys\
1 row in set (0.00 sec)

-切换到从服务器，修改从服务器日志读取信息

mysql> CHANGE MASTER TO MASTER_LOG_FILE='mysql-bin.000013',MASTER_LOG_POS=154;
Query OK, 0 rows affected (0.01 sec)
#重启slave进程
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
#查看slave状态

mysql> show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.163.61
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000013
          Read_Master_Log_Pos: 154
               Relay_Log_File: localhost-relay-bin.000002
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000013
        #状态变成YES
             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: 154
              Relay_Log_Space: 531
              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: 61
                  Master_UUID: 6e8275ca-2708-11ea-b43e-000c29e7ba58
             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)