Replicação mestre-escravo MySQL
Preparação do experimento:
2 servidores MySQL:
mestre: 192.168.78.132
escravo: 192.168.78.148
Princípio de replicação mestre-escravo
- Habilite o log binário no mestre
- Quando os dados do mestre forem alterados, um log binário será gerado.
- O thread de despejo no mestre notificará o thread io no escravo para obter o log binário e, em seguida, gravá-lo no log de retransmissão do escravo.Em seguida, o thread SQL lerá o log de retransmissão recém-gerado e reproduzirá as operações no log binário, conseguindo assim que o escravo e os dados no mestre sejam exatamente os mesmos, mantendo a consistência.
1. Habilite logs binários
Habilite o log binário no servidor mestre,server_id=1
[root@mysql-master ~]# vim /etc/my.cnf
[mysqld]
...
#log bin
log_bin
server_id = 1
O log binário também pode ser habilitado no servidor escravo.server_id=2
[root@mysql-slave ~]# vim /etc/my.cnf
[mysqld]
...
#log bin
log_bin
server_id = 2
2. Sincronize os dados do banco de dados
Exporte o conteúdo do banco de dados do servidor mestre e importe-o para o servidor escravo
1.Exportar dados no Master
[root@mysql-master ~]# mysqldump -uroot -p"Sanchuang123#" --all-databases >/backup/all_db.sql
mysqldump: [Warning] Using a password on the command line interface can be insecure.
2. Importe dados para o escravo
Carregue o arquivo de dados para o servidor escravo e importe os dados para obter dados iniciais consistentes nos servidores mestre e escravo:
Operação no servidor mestre:
#需要先建立免密通道
[root@mysql-master ~]# scp /backup/all_db.sql 192.168.78.148:/root
all_db.sql 100% 885KB 79.4MB/s 00:00
Operação no servidor escravo:
[root@mysql-slave ~]# mysql -uroot -p'Sanchuang123#' <all_db.sql
mysql: [Warning] Using a password on the command line interface can be insecure.
3. Crie um novo usuário autorizado
Atualize o MySQL no servidor mestre para gerar um novo log para facilitar as operações subsequentes:
root@(none) 19:33 mysql>flush logs;
Query OK, 0 rows affected (0.01 sec)
root@(none) 19:36 mysql>show master status; #查看当前正在使用的二进制日志文件
+-------------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------------------+----------+--------------+------------------+-------------------+
| mysql-master-bin.000003 | 154 | | | |
+-------------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
Crie um novo usuário no MySQL no servidor mestre:
root@(none) 19:36 mysql>grant replication slave on *.* to 'sc'@'192.168.78.%' identified by 'Sanchuang123#';
Query OK, 0 rows affected, 1 warning (0.00 sec)
root@(none) 19:41 mysql>flush privileges; #刷新 MySQL 权限
Query OK, 0 rows affected (0.00 sec)
root@(none) 19:42 mysql>show show grants for 'sc'@'192.168.78.%'; #用于显示指定用户在 MySQL 中的授权信息
ERROR 1064 (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 'show grants for 'sc'@'192.168.78.%'' at line 1
root@(none) 19:42 mysql>show grants for 'sc'@'192.168.78.%';
+-------------------------------------------------------+
| Grants for sc@192.168.78.% |
+-------------------------------------------------------+
| GRANT REPLICATION SLAVE ON *.* TO 'sc'@'192.168.78.%' |
+-------------------------------------------------------+
1 row in set (0.01 sec)
4. Configure no servidor escravo
root@(none) 19:58 mysql>CHANGE MASTER TO MASTER_HOST='192.168.78.132' ,
-> MASTER_USER='sc', #创建的授权用户
-> MASTER_PASSWORD='Sanchuang123#', #密码
-> MASTER_PORT=3306, #master的MySQL端口号
-> MASTER_LOG_FILE='mysql-master-bin.000003', #master正在使用的二进制文件
-> MASTER_LOG_POS=154; #二进制文件现在的pos
Query OK, 0 rows affected, 2 warnings (0.00 sec)
Verifique o status do servidor escravo:
root@(none) 19:58 mysql>show slave status\G;
*************************** 1. row ***************************
Slave_IO_State:
Master_Host: 192.168.78.132
Master_User: sc
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-master-bin.000003
Read_Master_Log_Pos: 154
Relay_Log_File: mysql-slave-relay-bin.000001
Relay_Log_Pos: 4
Relay_Master_Log_File: mysql-master-bin.000003
Slave_IO_Running: No #从服务器的IO线程没有起来
Slave_SQL_Running: No #从服务器的SQL线程没有起来
Inicie o thread SQL:
root@(none) 20:01 mysql>stop slave; #停止从服务器上的主从复制
Query OK, 0 rows affected (0.00 sec)
root@(none) 20:03 mysql>start slave; #开启从服务器上的主从复制
Query OK, 0 rows affected (0.00 sec)
root@(none) 20:03 mysql>show slave status\G;
*************************** 1. row ***************************
Slave_IO_State:
Master_Host: 192.168.78.132
Master_User: sc
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-master-bin.000003
Read_Master_Log_Pos: 154
Relay_Log_File: mysql-slave-relay-bin.000001
Relay_Log_Pos: 4
Relay_Master_Log_File: mysql-master-bin.000003
Slave_IO_Running: No
Slave_SQL_Running: Yes #发现sql线程开启成功，io没有成功
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: 154
Relay_Log_Space: 154
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: 1593
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. #发现io不成功是uuid问题
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
Master_UUID:
Master_Info_File: /data/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp: 230717 20:03:35
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:
1 row in set (0.00 sec)
ERROR:
No query specified
Resolva o mesmo problema com UUID:
root@(none) 20:07 mysql> show variables like "%uuid%";
+---------------+--------------------------------------+
| Variable_name | Value |
+---------------+--------------------------------------+
| server_uuid | 8cccc5f7-be7a-11ed-8855-000c29398d80 |
+---------------+--------------------------------------+
1 row in set (0.00 sec)
Basta modificar alguns caracteres, apenas torná-los diferentes dos do servidor principal:
[root@mysql-slave ~]# cd /data/mysql #MySQL数据目录
[root@mysql-slave mysql]# vim auto.cnf
[auto]
server-uuid=8cccc5f7-be7a-11ed-8855-000c29398d81
[root@mysql-slave mysql]# service mysqld restart
Shutting down MySQL.... SUCCESS!
Starting MySQL. SUCCESS!
Problema resolvido com sucesso:
root@(none) 20:09 mysql>show slave status\G;
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 4
Current database: *** NONE ***
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.78.132
Master_User: sc
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-master-bin.000003
Read_Master_Log_Pos: 598
Relay_Log_File: mysql-slave-relay-bin.000003
Relay_Log_Pos: 771
Relay_Master_Log_File: mysql-master-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Após sucesso, visualize o arquivo:
[root@mysql-slave mysql]# cat master.info
25
mysql-master-bin.000003
598
192.168.78.132
sc
Sanchuang123#
3306
60
0
0
30.000
0
8cccc5f7-be7a-11ed-8855-000c29398d80
86400
0
[root@mysql-slave mysql]# cat relay-log.info
7
./mysql-slave-relay-bin.000003
771
mysql-master-bin.000003
598
0
0
1
Como o Mestre sabe quais servidores escravos existem?
root@(none) 19:51 mysql>SHOW SLAVE HOSTS;
+-----------+------+------+-----------+--------------------------------------+
| Server_id | Host | Port | Master_id | Slave_UUID |
+-----------+------+------+-----------+--------------------------------------+
| 2 | | 3306 | 1 | 8cccc5f7-be7a-11ed-8855-000c29398d81 |
+-----------+------+------+-----------+--------------------------------------+
1 row in set (0.00 sec)
5. Verifique se a replicação mestre-escravo foi bem-sucedida
No servidor mestre, crie um banco de dados e tabelas:
root@(none) 20:16 mysql>create database db1;
Query OK, 1 row affected (0.00 sec)
root@(none) 20:19 mysql>use db1
Database changed
root@db1 20:19 mysql>create table t1(id int ,name varchar(20));
Query OK, 0 rows affected (0.01 sec)
root@db1 20:20 mysql> insert into t1 values(1,'lisi');
Query OK, 1 row affected (0.00 sec)
root@db1 20:20 mysql>select * from t1;
+------+------+
| id | name |
+------+------+
| 1 | lisi |
+------+------+
1 row in set (0.00 sec)
Verifique se existe no servidor escravo:
root@(none) 20:16 mysql>use db1
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
root@db1 20:22 mysql>select * from t1;
+------+------+
| id | name |
+------+------+
| 1 | lisi |
+------+------+
1 row in set (0.00 sec)