系统环境：Centos7

主：192.168.8.162

从：192.168.8.127

前提条件

a.关闭防火墙

systemctl stop firewalld

关闭防火墙开机自启

systemctl disable firewalld

b.关闭selinux

vi /etc/selinux/config

将SELINUX=enforcing改为SELINUX=disabled

设置后需要重启才能生效

首先两台数据库安装mysql8.0

1.查看本机是否安装mariadb

3.安装mysql8.0的yum源

yum -y install https://dev.mysql.com/get/mysql80-community-release-el7-1.noarch.rpm

执行 yum search mysql  如果出现 mysql-community-server.x86_64 则安装源成功

4.安装mysql8.0

yum -y install mysql-community-server.x86_64

5.启动mysql

systemctl start mysqld

开机自启：systemctl enable mysqld

6.查看mysql版本

mysql -V

7.设置mysql密码

cat /var/log/mysqld.log

!/dChNphO81E  mysql随机生成的密码

修改密码

mysqladmin -u root -p password

9.主库配置

创建一个复制用户，授予用户 slave REPLICATION SLAVE权限和REPLICATION CLIENT权限，用于在主从库之间同步数据。

mysql -uroot -p

USE mysql;

CREATE USER slave IDENTIFIED BY 'Slave@123';

GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'slave'@'%';

FLUSH PRIVILEGES;

vi /etc/my.cnf

添加

server-id=162

log-bin=/var/lib/mysql/mysql-bin

重启数据库

systemctl restart mysqld

连接数据库

mysql -uroot -p

查看日志情况

SHOW MASTER STATUS;

记录下File和Position的值

10.从库配置

vi /etc/my.cnf

添加 server-id=127

重启数据库

systemctl restart mysqld

连接数据库

mysql -uroot -p

停止主从

stop slave

从数据连接主数据库：

change master to master_host='192.168.8.162', master_user='slave', master_password='Slave@123', master_port=3306, master_log_file='mysql-bin.000002', master_log_pos= 1013, master_connect_retry=30;

host、user、password、port为主库的ip、用户名和密码、端口

master_log_file为从主库哪个日志读数据即上文中的File

master_log_pos为从哪里开始读即上文中的Position

master_connect_retry为超时重试时间

开始主从

start slave

查看同步状态

show slave status \G;

SlaveIORunning 和 SlaveSQLRunning 都是Yes说明主从复制已经开启。

若 Slave_IO_Running为Connecting可能是mysql8的密码规则问题

主数据库修改slave的密码规则即可：

ALTER USER 'slave'@'%' IDENTIFIED WITH mysql_native_password BY 'Slave@123';

mysql>stop slave;

Query OK,0 rows affected (0.00sec)

mysql> change master to master_host='192.168.8.162', master_user='slave', master_password='Slave@123', master_port=3306, master_log_file='mysql-bin.000002', master_log_pos= 1013, master_connect_retry=30;

Query OK,0 rows affected, 2 warnings (0.01sec)

mysql>show slave statu \G;

ERROR1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'statu' at line 1ERROR:

No query specified

mysql>show slave status \G;*************************** 1. row ***************************Slave_IO_State:

Master_Host:192.168.8.162Master_User: slave

Master_Port:3306Connect_Retry:30Master_Log_File: mysql-bin.000002Read_Master_Log_Pos:1013Relay_Log_File: localhost-relay-bin.000001Relay_Log_Pos:4Relay_Master_Log_File: mysql-bin.000002Slave_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:0Last_Error:

Skip_Counter:0Exec_Master_Log_Pos:1013Relay_Log_Space:155Until_Condition: None

Until_Log_File:

Until_Log_Pos:0Master_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:2061Last_IO_Error: error connecting to master'slave@192.168.8.162:3306' - retry-time: 30 retries: 5 message: Authentication plugin 'caching_sha2_password'reported error: Authentication requires secure connection.

Last_SQL_Errno:0Last_SQL_Error:

Replicate_Ignore_Server_Ids:

Master_Server_Id:0Master_UUID:

Master_Info_File: mysql.slave_master_info

SQL_Delay:0SQL_Remaining_Delay: NULL

Slave_SQL_Running_State:

Master_Retry_Count:86400Master_Bind:

Last_IO_Error_Timestamp:190912 11:02:03Last_SQL_Error_Timestamp:

Master_SSL_Crl:

Master_SSL_Crlpath:

Retrieved_Gtid_Set:

Executed_Gtid_Set:

Auto_Position:0Replicate_Rewrite_DB:

Channel_Name:

Master_TLS_Version:

Master_public_key_path:

Get_master_public_key:0Network_Namespace:1 row in set (0.00sec)

ERROR:

No query specified

mysql>start slave;

Query OK,0 rows affected (0.01sec)

mysql>show slave status \G;*************************** 1. row ***************************Slave_IO_State: Waitingfor master to send eventMaster_Host:192.168.8.162Master_User: slave

Master_Port:3306Connect_Retry:30Master_Log_File: mysql-bin.000002Read_Master_Log_Pos:1013Relay_Log_File: localhost-relay-bin.000002Relay_Log_Pos:322Relay_Master_Log_File: mysql-bin.000002Slave_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:0Last_Error:

Skip_Counter:0Exec_Master_Log_Pos:1013Relay_Log_Space:534Until_Condition: None

Until_Log_File:

Until_Log_Pos:0Master_SSL_Allowed: No

Master_SSL_CA_File:

Master_SSL_CA_Path:

Master_SSL_Cert:

Master_SSL_Cipher:

Master_SSL_Key:

Seconds_Behind_Master:0Master_SSL_Verify_Server_Cert: No

Last_IO_Errno:0Last_IO_Error:

Last_SQL_Errno:0Last_SQL_Error:

Replicate_Ignore_Server_Ids:

Master_Server_Id:162Master_UUID: 0d26dbd8-d501-11e9-9f3d-000c29e24dcf

Master_Info_File: mysql.slave_master_info

SQL_Delay:0SQL_Remaining_Delay: NULL

Slave_SQL_Running_State: Slave has read all relay log; waitingformore updates

Master_Retry_Count:86400Master_Bind:

Last_IO_Error_Timestamp:

Last_SQL_Error_Timestamp:

Master_SSL_Crl:

Master_SSL_Crlpath:

Retrieved_Gtid_Set:

Executed_Gtid_Set:

Auto_Position:0Replicate_Rewrite_DB:

Channel_Name:

Master_TLS_Version:

Master_public_key_path:

Get_master_public_key:0Network_Namespace:1 row in set (0.00sec)

ERROR:

No query specified

11.测试主从数据库

主库创建test数据库

create database test;

测试完成！

如果想只同步某一个数据库

可以在主库的my.cnf

添加

binlog-do-db：binlog日志记录哪个db

或者在从库的my.cnf添加

replicate-do-db：需要复制的数据库名

replicate-ignore-db：不需要复制的数据库名