文章目录
MYSQL-mysql常见主从复制技术实现全过程
1. mysql主从同步（M-S）
主从同步原理：
实验环境：
| 主机名 | IP地址 | mysql版本 | 主从复制的身份 |
|---|---|---|---|
| master | 192.168.8.198 | mysql5.7.31 | 主Master |
| slave1 | 192.168.8.197 | mysql5.7.31 | 从Slave |
在master上创建测试数据：
# 创建用于主从同步的数据库
[root@master ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.7.31 MySQL Community Server (GPL)
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
mysql> create database test;
Query OK, 1 row affected (0.00 sec)
mysql> use test;
Database changed
mysql> create table emp(id int primary key,name varchar(20));
Query OK, 0 rows affected (0.08 sec)
mysql> insert into emp values(1,'haha');
Query OK, 1 row affected (0.05 sec)
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
+----+------+
1 row in set (0.00 sec)
配置master为mysql主：
# 添加以下内容，表示该mysql服务器为主，标识符为1，启动二进制日志，可同步test数据库，不可同步mysql数据库。
[root@master ~]# vim /etc/my.cnf
[mysql]
default-character-set=utf8
[mysqld]
default-storage-engine=INNODB
character_set_server=utf8
log-bin=mysql-bin-master
server-id=1
binlog-do-db=test
binlog-ignore-db=mysql
[root@master ~]# systemctl restart mysqld
# set global validate_password_policy=0; 密码策略等级
# set global validate_password_length=1; 密码长度最小值
# 创建一个slave用户，可以在从服务器使用该用户连接主服务器，并且授予replication slave的权限。
[root@master ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.31-log MySQL Community Server (GPL)
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> grant replication slave on *.* to [email protected] identified by 'Abong123.';
Query OK, 0 rows affected, 1 warning (0.05 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
mysql> exit
Bye
查看主mysql的状态：
[root@master ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.31-log MySQL Community Server (GPL)
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show master status; # 可以看到主服务器的同步复制信息
+-------------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+-------------------------+----------+--------------+------------------+
| mysql-bin-master.000001 | 602 | test | mysql |
+-------------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
mysql> exit
Bye
# mysql> show binlog events\G;
# 也可以使用以上命令查看主服务器信息。
# 可以看到，主服务器上已经产生日志信息了。
[root@master ~]# ll /var/lib/mysql/mysql-bin-master.*
-rw-r-----. 1 mysql mysql 602 9月 19 20:50 /var/lib/mysql/mysql-bin-master.000001
-rw-r-----. 1 mysql mysql 26 9月 19 20:45 /var/lib/mysql/mysql-bin-master.index
在进行主从同步之前，要保证主从数据库的一致性。这里将要同步复制的test数据库导出，然后再导入到从库中。
[root@master ~]# mysqldump -uroot -pAbong123. test > test.sql
[root@master ~]# scp test.sql [email protected]:/root/
[email protected]'s password:
test.sql 100% 1831 407.4KB/s 00:00
在从服务器上使用slave用户连接主库时，可以先检查主库的3306端口号是否开放。
[root@master ~]# firewall-cmd --permanent --zone=public --add-port=3306/tcp
success
[root@master ~]# firewall-cmd --reload
success
[root@master ~]# netstat -antup | grep mysql
tcp6 0 0 :::3306 :::* LISTEN 9526/mysqld
[root@master ~]# firewall-cmd --list-port
3306/tcp
使用slave用户连接主库：
[root@slave1 ~]# mysql -uslave -p -h 192.168.8.198
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.31-log MySQL Community Server (GPL)
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases; # 由于slave用户仅有复制权限，故无法看到主库上的其他数据库。
+--------------------+
| Database |
+--------------------+
| information_schema |
+--------------------+
1 row in set (0.00 sec)
mysql> exit
Bye
# 从库上创建test数据库，并导入复制前的数据
[root@slave1 ~]# mysql -uroot -pAbong123.
mysql> create database test;
Query OK, 1 row affected (0.05 sec)
mysql> exit
Bye
[root@slave1 ~]# mysql -uroot -pAbong123. test < test.sql
[root@slave1 ~]# mysql -uroot -pAbong123.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
+--------------------+
5 rows in set (0.00 sec)
配置从库：
[root@slave1 ~]# vim /etc/my.cnf
[mysqld]
server-id=2
[root@slave1 ~]# systemctl restart mysqld
# 在从库上配置主库信息，用于连接主库
[root@slave1 ~]# mysql -uroot -p
Enter password:
mysql> stop slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)
# 修改从库所对应的主库信息。
mysql> change master to master_host='192.168.8.198',master_port=3306,master_user='slave',master_password='Abong123.',master_log_file='mysql-bin-master.000001',master_log_pos= 602;
Query OK, 0 rows affected, 2 warnings (0.08 sec)
#master_host 【主服务器的IP地址】
#master_port 【主服务器的端口】
#master_log_file 【show master status显示的File列：mysql-bin-master.000001】
#master_log_pos 【show master status显示的Position列：602】
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
# 查看从库状态的时候，没连上有一个报错。说是mysql服务器ID冲突了。
mysql> show slave status\G;
Slave_IO_Running: No
Slave_SQL_Running: Yes
Last_IO_Error: Fatal error: The slave I/O thread stops because master and slave have equal MySQL server UUIDs; these UUIDs must be different for replication to work.
检查并修复mysql服务器ID冲突的问题：
可能是因为克隆虚拟机导致的。
# 主库
mysql> show variables like 'server_id';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id | 1 |
+---------------+-------+
1 row in set (0.07 sec)
# 从库
mysql> show variables like 'server_id';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id | 2 |
+---------------+-------+
1 row in set (0.08 sec)
# uuid真的冲突了！！！
[root@master ~]# cat /var/lib/mysql/auto.cnf
[auto]
server-uuid=30e19a3e-f1de-11ea-99f9-000c29ebd724
[root@slave1 ~]# cat /var/lib/mysql/auto.cnf
[auto]
server-uuid=30e19a3e-f1de-11ea-99f9-000c29ebd724
# 移除从库的uuid文件，然后重启mysql服务生成新的uuid文件。
# 可以看到，和主库的不一样了。
[root@slave1 ~]# mv /var/lib/mysql/auto.cnf /tmp/
[root@slave1 ~]# systemctl restart mysqld
[root@slave1 ~]# cat /var/lib/mysql/auto.cnf
[auto]
server-uuid=7be7fc33-fa7c-11ea-bf9e-000c29aab0d2
再次查看从库的连接情况：
# 可以看到已经连上了，而且没有报错。
mysql> show slave status\G;
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
在主库上查看主从复制情况：
mysql> show processlist\G;
*************************** 1. row ***************************
Id: 13
User: slave
Host: 192.168.8.197:48976
db: NULL
Command: Binlog Dump
Time: 175
State: Master has sent all binlog to slave; waiting for more updates
Info: NULL
至此，mysql主从同步复制已经部署完毕了。以下测试下结果：
# 主库插入数据
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
+----+------+
1 row in set (0.00 sec)
mysql> insert into emp values(2,'xixi');
Query OK, 1 row affected (0.06 sec)
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
+----+------+
2 rows in set (0.00 sec)
# 可以看到从库也有数据了。
mysql> use test;
Database changed
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
+----+------+
2 rows in set (0.00 sec)
注意：由于主库被删，从库也会对应被删除，故定期对主库进行备份是必须的。
2. mysql双向主从同步复制（M-M）
| host | IP地址 | mysql版本 | 主从复制的身份 |
|---|---|---|---|
| master1 | 192.168.8.198 | mysql5.7.31 | 主master1，从slave1 |
| master2 | 192.168.8.197 | mysql5.7.31 | 主master2，从slave2 |
由于主从同步复制是通过主上的二进制日志来实现的，这里先清空下之前主从同步所产生的二进制日志。
[root@master1 ~]# ll /var/lib/mysql/mysql-bin-master.*
-rw-r-----. 1 mysql mysql 864 9月 20 17:10 /var/lib/mysql/mysql-bin-master.000001
-rw-r-----. 1 mysql mysql 154 9月 20 17:10 /var/lib/mysql/mysql-bin-master.000002
-rw-r-----. 1 mysql mysql 52 9月 20 17:10 /var/lib/mysql/mysql-bin-master.index
[root@master1 ~]# mysql -uroot -pAbong123.
mysql> reset master; # 清空原先的master二进制日志
Query OK, 0 rows affected (0.01 sec)
mysql> show master status\G; # 可以看到主库的情况。File和Position
*************************** 1. row ***************************
File: mysql-bin-master.000001
Position: 154
Binlog_Do_DB: test
Binlog_Ignore_DB: mysql
Executed_Gtid_Set:
1 row in set (0.00 sec)
ERROR:
No query specified
mysql> exit
Bye
# 查看下二进制日志的情况，可以看到是使用二进制日志文件mysql-bin-master.000001写入日志。
[root@master1 ~]# ll /var/lib/mysql/mysql-bin-master.*
-rw-r-----. 1 mysql mysql 154 9月 20 17:18 /var/lib/mysql/mysql-bin-master.000001
-rw-r-----. 1 mysql mysql 26 9月 20 17:18 /var/lib/mysql/mysql-bin-master.index
配置主master1、从slave2：
①修改/etc/my.cnf文件为主master1，启动二进制日志。
[root@master1 ~]# vim /etc/my.cnf
[mysqld]
log-bin=mysql-bin-master # 开启二进制日志，且二进制文件前缀名为mysql-bin-master
server-id=1 # 主master的id
binlog-do-db=test # 同步的数据库
binlog-ignore-db=mysql # 不同步的数据库
[root@master1 ~]# systemctl restart mysqld
②创建slave用户，允许在其他主机登录，并授予复制权限。
[root@master1 ~]# mysql -uroot -p
Enter password:
mysql> grant replication slave on *.* to [email protected] identified by 'Abong123.';
Query OK, 0 rows affected, 1 warning (0.01 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.05 sec)
mysql> exit
Bye
③从库测试slave用户登录主库情况
[root@master1 ~]# firewall-cmd --list-port
3306/tcp
[root@master2 ~]# mysql -uslave -p -h 192.168.8.198
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.7.31-log MySQL Community Server (GPL)
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
+--------------------+
1 row in set (0.00 sec)
mysql> exit
Bye
④配置从库信息，并在从库上修改指向主库的信息，检查slave状态。
[root@master2 ~]# vim /etc/my.cnf
[mysqld]
log-bin=mysql-bin-master
server-id=2
binlog-do-db=test
binlog-ignore-db=mysqs
# file mysql-bin-master.000001
# position 154
mysql> stop slave;
Query OK, 0 rows affected (0.01 sec)
mysql> change master to master_host='192.168.8.198',master_port=3306,master_user='slave',master_password='Abong123.',master_log_file='mysql-bin-master.000001',master_log_pos=154;
Query OK, 0 rows affected, 2 warnings (0.06 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> start slave;
Query OK, 0 rows affected (0.01 sec)
mysql> show slave status\G; #可以看到从库已经连上主库了。
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
配置主master2、从slave1：
①修改/etc/my.cnf文件为主master2，启动二进制日志。
[root@master2 ~]# cat /etc/my.cnf
[mysqld]
log-bin=mysql-bin-master
server-id=2
binlog-do-db=test
binlog-ignore-db=mysql
[root@master2 ~]# systemctl restart mysqld
②创建slave用户，允许在其他主机登录，并授予复制权限。
[root@master2 ~]# mysql -uroot -p
Enter password:
mysql> grant replication slave on *.* to [email protected] identified by 'Abong123.';
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
mysql> exit
Bye
③从库测试slave用户登录主库情况
# 开放master2上的3306端口，允许被访问。
[root@master2 ~]# firewall-cmd --list-port
[root@master2 ~]# firewall-cmd --permanent --zone=public --add-port=3306/tcp
success
[root@master2 ~]# firewall-cmd --reload
success
[root@master2 ~]# firewall-cmd --list-port
3306/tcp
# 在master1上测试连接
[root@master1 ~]# mysql -uslave -p -h 192.168.8.197
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.31-log MySQL Community Server (GPL)
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
+--------------------+
1 row in set (0.05 sec)
mysql> exit
Bye
④从库上修改指向主库的信息，并检查slave状态。
# 在master2主库上查看主库信息
[root@master2 ~]# mysql -uroot -p
Enter password:
mysql> show master status\G;
*************************** 1. row ***************************
File: mysql-bin-master.000001
Position: 602
Binlog_Do_DB: test
Binlog_Ignore_DB: mysql
Executed_Gtid_Set:
1 row in set (0.00 sec)
在master1上进行相应的配置：
[root@master1 ~]# mysql -uroot -p
Enter password:
mysql> stop slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> change master to master_host='192.168.8.197',master_port=3306,master_user='slave',master_password='Abong123.',master_log_file='mysql-bin-master.000001',master_log_pos=602;
Query OK, 0 rows affected, 2 warnings (0.11 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G;
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
至此，master1和master2已经互为主从。测试下数据同步复制情况：
# master1上写入数据
[root@master1 ~]# mysql -uroot -p
Enter password:
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
+----+------+
2 rows in set (0.00 sec)
mysql> insert into emp values(3,'ohoh');
Query OK, 1 row affected (0.06 sec)
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 3 | ohoh |
+----+------+
3 rows in set (0.00 sec)
# master2检测是否同步数据，发现并没有同步。查看slave的状态会发现没连上。
[root@master2 ~]# mysql -uroot -p
Enter password:
mysql> use test;
Database changed
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
+----+------+
2 rows in set (0.00 sec)
mysql> show slave status\G;
Slave_IO_Running: No
Slave_SQL_Running: No
===========================================
# 从master1上获取master信息
mysql> show master status\G;
*************************** 1. row ***************************
File: mysql-bin-master.000001
Position: 154
Binlog_Do_DB: test
Binlog_Ignore_DB: mysql
Executed_Gtid_Set:
1 row in set (0.00 sec)
ERROR:
No query specified
# master2重启配置salve,启动slave的时候报错，使用reset slave命名重置slave即可启动。
mysql> stop slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> change master to master_host='192.168.8.198',master_port=3306,master_user='slave',master_password='Abong123.',master_log_file='mysql-bin-master.000001',master_log_pos=154;
Query OK, 0 rows affected, 2 warnings (0.07 sec)
mysql> start slave;
ERROR 1872 (HY000): Slave failed to initialize relay log info structure from the repository
mysql> reset slave;
Query OK, 0 rows affected (0.06 sec)
mysql> start slave;
Query OK, 0 rows affected (0.07 sec)
mysql> show slave status\G; # 可以看到，从库重新连上主库了。
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
注意：主从同步，若数据存在不一致，即当主库执行删除操作，而从库不能执行删除操作，那从库会报错并停止数据同步复制。可以认为是一种同步复制堵塞。
修复同步复制堵塞：
# 首先修复主从同步连接：
# 查看主库信息
mysql> show master status\G;
*************************** 1. row ***************************
File: mysql-bin-master.000001
Position: 678
Binlog_Do_DB: test
Binlog_Ignore_DB: mysql
Executed_Gtid_Set:
1 row in set (0.00 sec)
# 在从库上修改对应的主库信息
mysql> stop slave;
Query OK, 0 rows affected (0.00 sec)
mysql> reset slave;
Query OK, 0 rows affected (0.06 sec)
mysql> change master to master_host='192.168.8.198',master_port=3306,master_user='slave',master_password='Abong123.',master_log_file='mysql-bin-master.000001',master_log_pos=678;
Query OK, 0 rows affected, 2 warnings (0.07 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G;
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
# 手动同步两个数据库，使得数据保持一致。
# 备份test数据库
[root@master1 ~]# mysqldump -uroot -p test > test.sql
Enter password:
[root@master1 ~]# ll test.sql
-rw-r--r--. 1 root root 1864 9月 20 21:12 test.sql
[root@master1 ~]# scp test.sql [email protected]:/root/
[email protected]'s password:
test.sql 100% 1864 605.5KB/s 00:00
[root@master2 ~]# mysql -uroot -p
Enter password:
mysql> drop database test;
Query OK, 1 row affected (0.06 sec)
mysql> create database test;
Query OK, 1 row affected (0.00 sec)
mysql> exit
Bye
[root@master2 ~]# mysql -uroot -p test < test.sql
Enter password:
再来测试一遍：
# master1上删除数据：
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 4 | abab |
| 5 | lala |
+----+------+
4 rows in set (0.00 sec)
mysql> delete from emp where id=5;
Query OK, 1 row affected (0.01 sec)
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 4 | abab |
+----+------+
3 rows in set (0.00 sec)
# 在master2上也可以看到数据被删除了。
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 4 | abab |
+----+------+
3 rows in set (0.00 sec)
# master2上插入数据
mysql> insert into emp values(3,'ohoh');
Query OK, 1 row affected (0.01 sec)
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 3 | ohoh |
| 4 | abab |
+----+------+
4 rows in set (0.00 sec)
# master1上也可以看到有数据插入
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 3 | ohoh |
| 4 | abab |
+----+------+
4 rows in set (0.00 sec)
从上面的实验结果可以看出，主主同步已经测试成功了。
mysql双主的架构，并非是负载均衡，只能说两台mysql服务器都可以提供准确的数据，也可以进行写操作。
3. 部署MSS模型
| 主机名 | IP地址 | mysql版本 | 主从复制的身份 |
|---|---|---|---|
| master | 192.168.8.198 | mysql5.7.31 | master |
| slave1 | 192.168.8.197 | mysql5.7.31 | slave中继 |
| slave2 | 192.168.8.199 | mysql5.7.31 | slave |
配置主库：
# 在主库上创建中继用户repl，并授予replication slave权限，允许在192.168.8.网段的主机上登录。
[root@master ~]# mysql -uroot -p
Enter password:
mysql> grant replication slave on *.* to repl@'192.168.8.%' identified by 'Abong123.';
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> exit
Bye
# 将主库的数据导出并导入到中继库和从库
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| emp |
+----------------+
1 row in set (0.00 sec)
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 3 | ohoh |
| 4 | abab |
+----+------+
4 rows in set (0.01 sec)
[root@master ~]# mysqldump -uroot -p test > test.sql
Enter password:
[root@master ~]# ll test.sql
-rw-r--r--. 1 root root 1864 9月 22 19:41 test.sql
# 编辑主库的my.cnf文件：
[root@master ~]# vim /etc/my.cnf
[mysqld]
log-bin=mysql-bin-master
server-id=1
binlog-do-db=test
binlog-ignore-db=mysql
sync-binlog=1
binlog-format=row
# 重启mysqlf服务
[root@master ~]# systemctl restart mysqld
# 将数据库发送到中继库和从库上
[root@master ~]# scp test.sql 192.168.8.197:/root/
[root@master ~]# scp test.sql 192.168.8.199:/root/
配置中继库：
# 中继库导入数据库：
[root@slave1 ~]# mysql -uroot -p
Enter password:
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
mysql> create database test;
Query OK, 1 row affected (0.01 sec)
mysql> exit
Bye
[root@slave1 ~]# mysql -uroot -p test < test.sql
Enter password:
# 编辑中继库的my.cnf文件
[root@slave1 ~]# vim /etc/my.cnf
[mysqld]
log-bin=mysql-bin-slave1
server-id=2
log-slave-updates=1
binlog-format=row
[root@slave1 ~]# systemctl restart mysqld
# 修改中继库的master配置，指向主库
mysql> show master status\G; # 主库配置
*************************** 1. row ***************************
File: mysql-bin-master.000001
Position: 154
Binlog_Do_DB: test
Binlog_Ignore_DB: mysql
Executed_Gtid_Set:
1 row in set (0.00 sec)
# 中继库配置
mysql> stop slave;
Query OK, 0 rows affected (0.02 sec)
mysql> reset slave;
Query OK, 0 rows affected (0.02 sec)
mysql> change master to master_host='192.168.8.198',master_port=3306,master_user='repl',master_password='Abong123.',master_log_file='mysql-bin-master.000001',master_log_pos=154;
Query OK, 0 rows affected, 2 warnings (0.03 sec)
mysql> start slave;
Query OK, 0 rows affected (0.02 sec)
mysql> show slave status\G;
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
# 在中继库上创建中继用户repl，并授予replication slave权限，允许在192.168.8.199(从库)上登录。
mysql> grant replication slave on *.* to [email protected] identified by 'Abong123.';
Query OK, 0 rows affected, 1 warning (0.01 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
mysql> exit
Bye
此时，主库和中继库已经建立了同步复制关系。
配置从库：
# 从库导入数据库
[root@slave2 ~]# mysql -uroot -p
Enter password:
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
mysql> create database test;
Query OK, 1 row affected (0.00 sec)
mysql> exit;
Bye
[root@slave2 ~]# mysql -uroot -p test < test.sql
Enter password:
# 修改my.cnf文件
[root@slave2 ~]# vim /etc/my.cnf
server-id=3
log-bin=mysql-bin-slave2
binlog-format=row
# 重启服务
[root@slave2 ~]# systemctl restart mysqld
#开放从库的3306端口号
[root@slave2 ~]# firewall-cmd --permanent --zone=public --add-port=3306/tcp
success
[root@slave2 ~]# firewall-cmd --reload
success
[root@slave2 ~]# firewall-cmd --list-ports
3306/tcp
# 修改从库中的master配置，指向中继库
mysql> change master to master_host='192.168.8.197',master_port=3306,master_user='repl',master_password='Abong123.',master_log_file='mysql-bin-slave1.000001',master_log_pos=601;
Query OK, 0 rows affected, 2 warnings (0.02 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G;
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
至此，中继库和从库之间也建立了主从复制关系，但中继库并不进行写操作。
测试：在主库上插入一条数据，看从库上是否会同步该数据。
# 主库上插入数据
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| emp |
+----------------+
1 row in set (0.00 sec)
mysql> desc emp;
+-------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id | int(11) | NO | PRI | NULL | |
| name | varchar(20) | YES | | NULL | |
+-------+-------------+------+-----+---------+-------+
2 rows in set (0.00 sec)
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 3 | ohoh |
| 4 | abab |
+----+------+
4 rows in set (0.00 sec)
mysql> insert into emp values(5,'lala');
Query OK, 1 row affected (0.01 sec)
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 3 | ohoh |
| 4 | abab |
| 5 | lala |
+----+------+
5 rows in set (0.00 sec)
# 中继库也有记录
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 3 | ohoh |
| 4 | abab |
| 5 | lala |
+----+------+
5 rows in set (0.00 sec)
# 从库也有记录
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 3 | ohoh |
| 4 | abab |
| 5 | lala |
+----+------+
5 rows in set (0.00 sec)
为了让中继库不产生数据，仅有从库产生同步复制数据，可以对中继库中的表进行设置：
# 中继库操作：
mysql> set sql_log_bin=off;
Query OK, 0 rows affected (0.00 sec)
mysql> alter table test.emp ENGINE=blackhole;
Query OK, 5 rows affected (0.02 sec)
Records: 5 Duplicates: 0 Warnings: 0
mysql> set sql_log_bin=on;
Query OK, 0 rows affected (0.00 sec)
再测试一遍：
# 主库插入数据
mysql> insert into emp values(6,'nene');
Query OK, 1 row affected (0.01 sec)
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 3 | ohoh |
| 4 | abab |
| 5 | lala |
| 6 | nene |
+----+------+
6 rows in set (0.00 sec)
# 中继库无数据
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from emp;
Empty set (0.00 sec)
# 从库有同步数据
mysql> select * from emp;
+----+------+
| id | name |
+----+------+
| 1 | haha |
| 2 | xixi |
| 3 | ohoh |
| 4 | abab |
| 5 | lala |
| 6 | nene |
+----+------+
6 rows in set (0.00 sec)
4. mysql主从同步复制常见报错
4.1 因主从库的数据不一致导致从库同步复制停止
方法1：从库跳过指定数量的事务【适用从库较少的操作】
# 从库发现主从同步停了
mysql> show slave status\G;
# 主库上查看日志
mysql> show master status\G;
*************************** 1. row ***************************
File: mysql-bin-master.000001
Position: 678
Binlog_Do_DB: test
Binlog_Ignore_DB: mysql
Executed_Gtid_Set:
1 row in set (0.00 sec)
mysql> show binlog events in 'mysql-bin-master.000001' from 678\G;
Empty set (0.00 sec)
# 从库跳过这些事务
mysql> stop slave;
mysql> set global sql_slave_skip_counter=2; # 跳过2个事务，即这些事务主库上做了，但是从库上做不了，就会堵塞，所以要跳过。
mysql> start slave;
mysql> show slave status\G; # 再次查看是否连接上
方法2：主库关闭二进制日志再执行sql语句，执行完再开启二进制日志【适用从库较多的操作】
# 关闭bin-log
mysql> set sql_log_bin=off;
# 开启bin-log
mysql> set sql_log_bin=off;
4.2 从库对应的二进制主库日志（Master_Log_File）与主库上的二进制日志文件不一致
# 在从库上该命令调整。
change master to master_host='192.168.8.197',master_port=3306,master_user='repl',master_password='Abong123.',master_log_file='mysql-bin-slave1.000001',master_log_pos=601;