Linux——mysql主从复制配置

主从复制配置

主服务器配置：

追加信息
[root@localhost ~]# vim /etc/my.cnf
	[mysqld]
	server-id=11111
	log-bin=mysql-bin
重启服务：
[root@localhost ~]# systemctl restart mysqld.service 
进入mysql进行用户创建并给予相应权限：
mysql> create user 'qyx'@'%' identified with mysql_native_password by '054422';
Query OK, 0 rows affected (0.00 sec)

mysql> grant replication slave on *.* to 'qyx'@'%';
Query OK, 0 rows affected (0.01 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

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MySQL8中的默认认证插件是caching_sha2_password，该认证插件会导致从库连接不上主库，所以主库的用户创建时必须制定插件为mysql_native_password

从服务器上配置：

对从服务器进行配置，server-id必须和主服务器不同

追加信息
[root@localhost ~]# vim /etc/my.cnf
	[mysqld]
	server-id=22222       
	log-bin=mysql-bin
重启服务：
[root@localhost ~]# systemctl restart mysqld.service 
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主服务器上：

查询mysql主服务器信息：
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------------------------------------------------------------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                                                                   |
+------------------+----------+--------------+------------------+-------------------------------------------------------------------------------------+
| mysql-bin.000008 |      195 |              |                  | 0a60a26a-15fe-11ed-8d62-000c29335a5f:1-5,
853809b3-0322-11ed-96ea-000c29335a5f:1-19 |
+------------------+----------+--------------+------------------+-------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

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从服务器上配置：

配置主服务器的信息，master_log_pos为上面查询到的主服务器的position，master_log_file为上方查到的日志名（以防主从不同步）

mysql> stop slave;


mysql> change master to master_auto_position=0;
Query OK, 0 rows affected (0.01 sec)

mysql> change master to master_host='192.168.15.128',
    -> master_port=3306,
    -> master_user='qyx',
    -> master_password='054422',
    -> master_log_pos=195,
    -> master_log_file='myql-bin.000008';
Query OK, 0 rows affected, 2 warnings (0.01 sec)
mysql> start slave;
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从服务器上：

mysql> show slave status\G;                                                   
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.15.128
                  Master_User: qyx
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000008
          Read_Master_Log_Pos: 195
               Relay_Log_File: localhost-relay-bin.000002
                Relay_Log_Pos: 322
        Relay_Master_Log_File: mysql-bin.000008
             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: 195
              Relay_Log_Space: 534
              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: 11111
                  Master_UUID: 853809b3-0322-11ed-96ea-000c29335a5f
             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: 64fdcca9-16be-11ed-b56a-000c299be67d:1-2,
853809b3-0322-11ed-96ea-000c29335a5f:1-16
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
       Master_public_key_path: 
        Get_master_public_key: 0
            Network_Namespace: 
1 row in set (0.00 sec)

ERROR: 
No query specified
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出现以下信息才成功：

Slave_IO_Running: Yes
Slave_SQL_Running: Yes

​ Last_IO_Errno: 0

​ Last_SQL_Errno: 0

若错误提示有连个mysql具有相同的uuid。

则删除从服务器上的/etc/my.cnf文件再重新启动mysqld服务

查看从服务器上的通用日志，若没有打开，则打开

mysql> show variables like '%general%';
+------------------+------------------------------+
| Variable_name    | Value                        |
+------------------+------------------------------+
| general_log      | OFF                          |
| general_log_file | /var/lib/mysql/localhost.log |
+------------------+------------------------------+
2 rows in set (0.00 sec)

mysql> set @@global.general_log=on;
Query OK, 0 rows affected (0.01 sec)

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从服务器上追踪通用日志：

[root@localhost my.cnf.d]# tail -f /var/lib/mysql/localhost.log
/usr/libexec/mysqld, Version: 8.0.17 (Source distribution). started with:
Tcp port: 3306  Unix socket: /var/lib/mysql/mysql.sock
Time                 Id Command    Argument
2022-08-08T03:19:52.963828Z	    8 Query	show variables like '%general%'
2022-08-08T03:45:55.907963Z	    8 Quit	

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主服务器上创建数据库

mysql> create database nh;
Query OK, 1 row affected (0.02 sec)
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从服务器上出现追踪信息：

[root@localhost my.cnf.d]# tail -f /var/lib/mysql/localhost.log
/usr/libexec/mysqld, Version: 8.0.17 (Source distribution). started with:
Tcp port: 3306  Unix socket: /var/lib/mysql/mysql.sock
Time                 Id Command    Argument
2022-08-08T03:19:52.963828Z	    8 Query	show variables like '%general%'
2022-08-08T03:45:55.907963Z	    8 Quit	
2022-08-08T03:48:50.370896Z	   18 Query	create database nh
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进入从服务器进行认证，数据库复制成功：

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| db3                |
| example            |
| he                 |
| information_schema |
| myemployees        |
| mysql              |
| nextcloud          |
| nh                 |
| performance_schema |
| sys                |
+--------------------+
10 rows in set (0.03 sec)

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