mysql主从

环境搭建

  • 需要两台虚拟机
  • 在一个网段
[root@localhost ~]# virsh list --all
 Id    Name                           State
----------------------------------------------------
 8     master                         running
 9     slave                          running

[root@localhost ~]# 

我这里有两台虚拟机
一台master
一台slave

配置主服务器

编辑配置文件

[root@master ~]# vim /etc/my.cnf.d/server.cnf 
或者
[root@master ~]# vim /etc/my.cnf

编辑/etc/my.cnf.d/server.cnf 配置文件

[mysqld]
server-id = 1    #服务器的ID 和要比从的小
log-bin = mysqlbinlog       #日志文件名称
skip_name_resolve = ON      #禁用DNS解析   ON打开

/etc/my.cnf和子配置相同,两者只需改一个

启动mysql服务
[root@master ~]# systemctl restart mariadb
[root@master ~]# systemctl enable mariadb
[root@master ~]# 

配置从服务器

编辑子配置文件
/etc/my.cnf.d/server.cnf

[mysqld]
server-id = 2
skip_name_resolve = ON

重启服务并设置为开机启动

[root@slave ~]# systemctl restart mariadb 
[root@slave ~]# systemctl  enable mariadb 
[root@slave ~]# 

配置主从数据库

主节点

  • 在主服务器上创建用户,用于从服务器进行登录
    授予slave@'192.168.43.20' 用户所有权限
    MariaDB [(none)]> grant all on *.* to slave@'192.168.43.20' identified by '123';
    
  • 刷新授权表
    MariaDB [(none)]> flush privileges;
    
  • 查看主服务器状态
    MariaDB [(none)]> show master status;
    +--------------------+----------+--------------+------------------+
    | File               | Position | Binlog_Do_DB | Binlog_Ignore_DB |
    +--------------------+----------+--------------+------------------+
    | mysqlbinlog.000001 |      456 |              |                  |
    +--------------------+----------+--------------+------------------+
    1 row in set (0.00 sec)
    
    MariaDB [(none)]> 
    
  • 配置从节点
    连接主服务器,这里的MASTER_LOG_FILE和MASTER_LOG_POS要与刚才在主服务端所查看状态显示的数值相对性
    MariaDB [(none)]> change master to MASTER_HOST='192.168.43.20', MASTER_USER='slave',MASTER_PASSWORD='123',MASTER_LOG_FILE='mysqlbinlog.000001',MASTER_LOG_POS=456;
    Query OK, 0 rows affected (0.01 sec)
    
    MariaDB [(none)]> 
    
  • 查看从服务器的状态
    注意查看加#的选项
    MariaDB [(none)]> show slave status\G;
    *************************** 1. row ***************************
                  Slave_IO_State: 
                     Master_Host: 192.168.43.20
                     Master_User: slave
                     Master_Port: 3306
                   Connect_Retry: 60
                 Master_Log_File: mysqlbinlog.000001
             Read_Master_Log_Pos: 456
                  Relay_Log_File: mariadb-relay-bin.000001
                   Relay_Log_Pos: 4
           Relay_Master_Log_File: mysqlbinlog.000001
    #              Slave_IO_Running: No
    #              Slave_SQL_Running: No
                 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: 456
                 Relay_Log_Space: 245
                 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: 0
                   Last_IO_Error: 
                  Last_SQL_Errno: 0
                  Last_SQL_Error: 
     Replicate_Ignore_Server_Ids: 
                Master_Server_Id: 0
    1 row in set (0.00 sec)
    
    ERROR: No query specified
    
    MariaDB [(none)]> 
    

启动主从同步

MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.06 sec)

MariaDB [(none)]> 

查看从服务器的状态

MariaDB [(none)]> show slave status\G;
*************************** 1. row ***************************
            Slave_IO_State: Waiting for master to send event
               Master_Host: 192.168.43.10
               Master_User: slave
               Master_Port: 3306
             Connect_Retry: 60
           Master_Log_File: mysqlbinlog.000004
       Read_Master_Log_Pos: 245
            Relay_Log_File: mariadb-relay-bin.000002
             Relay_Log_Pos: 531
     Relay_Master_Log_File: mysqlbinlog.000004
#             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: 245
           Relay_Log_Space: 827
           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
1 row in set (0.00 sec)

ERROR: No query specified

MariaDB [(none)]> 

当从服务器出现以下状态需要查看主服务器防火墙的状态

MariaDB [(none)]> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Connecting to master
                  Master_Host: 192.168.43.10
                  Master_User: slave
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysqlbinlog.000004
          Read_Master_Log_Pos: 245
               Relay_Log_File: mariadb-relay-bin.000002
                Relay_Log_Pos: 531
        Relay_Master_Log_File: mysqlbinlog.000004
             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: 245
              Relay_Log_Space: 827
              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 'slave@192.168.43.10:3306' - retry-time: 60  retries: 86400  message: Can't connect to MySQL server on '192.168.43.10' (113)
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 1
1 row in set (0.00 sec)

ERROR: No query specified

MariaDB [(none)]> 

注意查看#号所显示的错误

  • 查看主服务器防火墙状态
[root@master ~]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
   Active: active (running) since Thu 2019-04-25 11:53:11 GMT; 6min ago
     Docs: man:firewalld(1)
 Main PID: 12795 (firewalld)
   CGroup: /system.slice/firewalld.service
           └─12795 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid

Apr 25 11:53:11 master systemd[1]: Starting firewalld - dynamic firewall daemon...
Apr 25 11:53:11 master systemd[1]: Started firewalld - dynamic firewall daemon.
[root@master ~]# 

将防火墙关闭重新连接即可

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