简述MySQL主从复制原理及其工作过程，配置一主两从并验证

 MySQL主从复制原理:MySQL主从复制是一种常用的数据同步技术，它通过将一个MySQL数据库服务器（主服务器）的数据实时复制到一个或多个从服务器，从而实现数据的备份、读写分离以及高可用性等目标.

基于binlog的主从同步

#主服务器配置
[root@localhost ~]# cat /etc/my.cnf | grep server_id
server_id=1

mysql> create user rep@'192.168.238.%' identified with mysql_native_password by 'MySQL@123';
Query OK, 0 rows affected (0.00 sec)


mysql> grant replication slave on *.* to rep@'192.168.238.%';
Query OK, 0 rows affected (0.00 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000001 |     1002 |              |                  |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

#两台从服务器配置
[root@localhost ~]# cat /etc/my.cnf | grep server_id
server_id=2
#[root@localhost ~]# cat /etc/my.cnf | grep server_id
#server_id=3


mysql> change master to
    -> master_host='192.168.238.135',
    -> master_user='rep',
    -> master_password='MySQL@123',
    -> master_log_file='binlog.000001',
    -> master_log_pos=1002;
Query OK, 0 rows affected, 8 warnings (0.01 sec)

mysql> start slave;
Query OK, 0 rows affected, 1 warning (0.01 sec)

mysql> show slave status \G
*************************** 1. row ***************************
               Slave_IO_State: 
                  Master_Host: 192.168.238.135
                  Master_User: rep
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: binlog.000001
          Read_Master_Log_Pos: 1002
               Relay_Log_File: localhost-relay-bin.000001
                Relay_Log_Pos: 4
        Relay_Master_Log_File: binlog.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: 1002
              Relay_Log_Space: 157
              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: 13117
                Last_IO_Error: Fatal error: The replica I/O thread stops because source and replica 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 replica but this does not always make sense; please check the manual before using it).
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 1
                  Master_UUID: 
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Replica has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 250211 15:50:38
     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
            Network_Namespace: 
1 row in set, 1 warning (0.00 sec)

#验证

#主服务器创建表
mysql> create database test;
Query OK, 1 row affected (0.01 sec)
 
 
#从服务器验证
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| KW                 |
| test               |
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
6 rows in set (0.01 sec)