搭建mysql主从复制(主主复制)

1：设主库允许远程连接(注意：设置账号密码必须使用的插件是mysql_native_password，其他的会连接失败)

#切换到mysql这个数据库，修改user表中的host，使其可以实现远程连接
mysql>use mysql;
mysql>update user set host ="%" where user ="root";
#改完之后一定要刷新信息
mysql>flush privileges;

2：主库开启bin-log日志在my.cnf的[mysqld]下添加

#修改主服务器Master
#修改配置文件
vim /etc/my.cnf
#主服务器唯一ID，这个id可以随便修改，只要不跟从服务器重复,注意连接是-,不是_
server-id=1
#启用二进制日志
log-bin=mysql-bin

2-1：重启主库mysql

[root@localhost ~]# systemctl retart mysql

2-2：查看主库server 相关信息

mysql>  show global variables like '%server%';
+---------------------------------+--------------------------------------+
| Variable_name                   | Value                                |
+---------------------------------+--------------------------------------+
| character_set_server            | utf8mb4                              |
| collation_server                | utf8mb4_0900_ai_ci                   |
| innodb_dedicated_server         | OFF                                  |
| innodb_ft_server_stopword_table |                                      |
| server_id                       | 1                                    |
| server_id_bits                  | 32                                   |
| server_uuid                     | b434ab49-df79-11ee-9c39-0242ac110002 |
+---------------------------------+--------------------------------------+
7 rows in set (0.00 sec)mysql>

2-2：查看主库是否开启bin-log日志

mysql>  show global variables like '%log%';

2-3：查看主库的最新状态

mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000004 |      157 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)mysql> FLUSH LOGS;
Query OK, 0 rows affected (0.01 sec)mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000005 |      157 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)mysql>

2-4：查看全部的二进制文件，可以选择一步一步恢复

mysql> SHOW BINARY LOGS;
+------------------+-----------+-----------+
| Log_name         | File_size | Encrypted |
+------------------+-----------+-----------+
| mysql-bin.000001 |       204 | No        |
| mysql-bin.000002 |       204 | No        |
| mysql-bin.000003 |       204 | No        |
| mysql-bin.000004 |       204 | No        |
| mysql-bin.000005 |       157 | No        |
+------------------+-----------+-----------+
5 rows in set (0.00 sec)mysql>

3：从库开启bin-log日志在my.cnf的[mysqld]下添加

#修改从服务器slave
修改配置文件：vim /etc/my.cnf
#从服务器唯一ID,注意连接是-,不是_
server-id=2
#启用中继日志
relay-log=mysql-relay

3-1：查看主库是否开启bin-log日志，从库也是一样

mysql>  show global variables like '%log%';

4：在主库创建一个账号slave，密码123456，并且授权连接

mysql>GRANT REPLICATION SLAVE ON *.* to 'slave'@'%' identified by '123456';

4-1：在从库指定主库(添加 主节点主机，访问主节点的用户名及密码，主节点二进制文件信息，注意：主节点的二进制文件一定要是二进制列表中的最后一个二进制文件。如果需要设置主主就是主库也执行如下的命令，ip，账号，密码换成从库的)

mysql> change master to master_host='192.168.11.47',master_user='root',master_password='root',master_log_file='mysql-bin.000005',master_log_pos=157;
Query OK, 0 rows affected, 8 warnings (0.01 sec)

5：检查从库复制功能状态（注意：Slave_IO_Running，Slave_SQL_Running，两个线程必须为yes状态，否则主从复制搭建不成功）

show slave status \G;

5-1：先停止从库的复制功能

mysql>stop slave;

5-2： 如果报错，异常原因，从库已经存在之前的relay log

mysql> start slave;
ERROR 1872 (HY000): Slave failed to initialize relay log info structure from the repository

5-3：解决方案，使用reset slave语句，清除master信息和relay日志信息，并创建全新的中继日志.

mysql> stop slave;
Query OK, 0 rows affected, 2 warnings (0.00 sec)
mysql> reset slave;
Query OK, 0 rows affected, 1 warning (0.01 sec)
mysql> change master to master_host='192.168.11.47',master_user='root',master_password='root',master_log_file='mysql-bin.000005',master_log_pos=157;
Query OK, 0 rows affected, 8 warnings (0.02 sec)
mysql> start slave;
Query OK, 0 rows affected, 1 warning (0.01 sec)

5-4：再启动从库的复制功能

mysql>start slave;

5-5：再查看从库的状态

show slave status \G;

6：keepAlived的配置文件权限必须是644