主从复制配置
####################主服务器配置###########################
1、修改主数据库mysql配置，找到主数据库的配置文件my.cnf(或者my.ini)，我的在/etc/mysql/my.cnf,在[mysqld]部分插入如下两行
[mysqld] log-bin=mysql-bin #开启二进制日志 server-id=1 #设置server-id
2、重启mysql，创建用于同步的用户账号
CREATE USER ‘test‘@‘192.168.56.150‘ IDENTIFIED BY ‘123456‘; GRANT REPLICATION SLAVE ON *.* TO ‘test‘@‘192.168.56.150‘; flush privileges;
3、查看master装填，记录二进制文件名(mysql-bin.000005)和位置(977)
mysql> show master status; +------------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+------------------+-------------------+ | mysql-bin.000005 | 977 | | | | +------------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)
#########################从服务器##################################
1、修改mysql配置，同样找到my.cnf配置文件，添加server-id
[mysqld] server-id=2 #设置server-id，必须唯一
2、重启mysql，打开mysql会话，执行同步SQL语句(需要主服务器主机名，登陆凭据，二进制文件的名称和位置)
CHANGE MASTER TO MASTER_HOST=‘192.168.56.149‘, MASTER_USER=‘test‘, MASTER_PASSWORD=‘123456‘, MASTER_LOG_FILE=‘mysql-bin.000005‘, MASTER_LOG_POS=516;
3、启动slave同步进程
start slave;
注意：关闭是stop slave;
4、查看slave状态
show slave status\G;
FAQ
1、如果Slave_IO_Running: Connecting，同时Last_IO_Errno: 2003，说明和主节点服务器无法通信
Relay_Master_Log_File: mysql-bin.000005 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: 120 Relay_Log_Space: 120 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: 2003 Last_IO_Error: error connecting to master ‘test@192.168.56.149:3306‘ - retry-time: 60 retries: 1 Last_SQL_Errno: 0 Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 0 Master_UUID: 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 the slave I/O thread to update it
解决方案：
1、ping主机是否通
2、从节点的设置账号和密码以及主节点IP是否正确 ，即MASTER_USER、MASTER_PASSWORD、MASTER_HOST、MASTER_LOG_FILE、MASTER_LOG_POS是否一致
3、关闭防火墙 即systemctl disable firewalld
4、关闭selinux 即selinux=disabled
原文：https://www.cnblogs.com/ywjfx/p/10264383.html