MySQL数据库集群技术主从复制一主一从详细讲解-编程知识

集群技术

集群概述 MySQL复制技术

集群目的

负载均衡
- 解决高并发
高可用HA
- 服务可用性
远程灾备
- 数据有效性

类型

一主一从
一主双从
双主双从

原理

概念
- 在主库上把数据更改（DDL DML DCL）记录到二进制日志（Binary Log）中。
- 备库I/O线程将主库上的日志复制到自己的中继日志（Relay Log）中。
- 备库SQL线程读取中继日志中的事件，将其重放到备库数据库之上。

环境
- 全新服务器-互相通信
- 全新安装mysql80-分别安装
- 配置域名解析

master1：192.168.142.139
slave1：192.168.142.140
[root@service ~]# vim /etc/hosts
192.168.142.139 master1
192.168.142.140 slave1

主服务器配置

部署一台新mysql服务器。准备好域名解析。

准备数据

mysql> create database master1db;
Query OK, 1 row affected (0.05 sec)mysql> use master1db;
Database changed
mysql> create table master1db.master1tab(name char(50));
Query OK, 0 rows affected (0.03 sec)mysql> insert into master1db.master1tab values (1111);
Query OK, 1 row affected (0.02 sec)mysql> insert into master1db.master1tab values (2222);
Query OK, 1 row affected (0.00 sec)

开启二进制日志

[root@service ~]# vim /etc/my.cnf
server-id=1
log_bin
[root@service ~]# systemctl restart mysqld

创建复制用户

mysql> create user 'rep'@'192.168.142.%' identified by 'Wyxbuke00.';
Query OK, 0 rows affected (0.03 sec)mysql> grant replication slave,replication client on *.* to 'rep'@'192.168.142.%' ;
Query OK, 0 rows affected (0.00 sec)

备份master数据库的数据

[root@service ~]# mysqldump -uroot -p'Wyxbuke00.' --all-databases --single-transaction --master-data=2 --flush-logs > `date +%F` -mysql-all.sql
[root@service ~]# ll
总用量 444848
-rw-r--r--. 1 root root         0  2月 22 16:12 2024-02-22
-rw-r--r--. 1 root root   1288580  2月 22 16:10 2024-02-22-mysql-all.sql
观察二进制日志分割点
-- CHANGE MASTER TO MASTER_LOG_FILE='service-bin.000003', MASTER_LOG_POS=157;

准备数据2

mysql> insert into master1db.master1tab values (33333333);
Query OK, 1 row affected (0.00 sec)mysql> insert into master1db.master1tab values (44444);
Query OK, 1 row affected (0.00 sec)

从服务器配置

测试rep用户是否可用

[root@server ~]# mysql -urep -pWyxbuke00. -h master1
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>

启动服务器序号

[root@server ~]# systemctl stop firewalld
[root@server ~]# setenforce 0
[root@server ~]# vim /etc/my.cnf
不用在从设备上开启二进制日志，没有人向从设备请求日志。server-id=2
[root@server ~]# systemctl restart mysqld

手动同步数据

从主服务器发送
[root@service ~]# scp 2024-02-22-mysql-all.sql slave1:/tmp/
root@slave1's password: 
2024-02-22-mysql-all.sql
到从服务器查看
[root@server ~]# ls /tmp
2024-02-22-mysql-all.sql  [root@server ~]# mysql -u root -p
Enter password:
mysql> set sql_log_bin=0;\
Query OK, 0 rows affected (0.00 sec)mysql> source /tmp/2024-02-22-mysql-all.sql ;
Query OK, 0 rows affected (0.00 sec)mysql> use master1db;
Database changed
mysql> select *from master1db.master1tab;
+------+
| name |
+------+
| 1111 |
| 2222 |
+------+
2 rows in set (0.00 sec)

设置主服务器

mysql> change master to master_host='master1', master_user='rep', master_password='Wyxbuke00.',master_log_file='localhost-bin.000004',master_log_pos=157;
Query OK, 0 rows affected, 8 warnings (0.01 sec)
CHANGE MASTER TO MASTER_LOG_FILE=‘mysqld-bin.000004’,MASTER_LOG_POS=157;

启动从设备

mysql> start slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)

查看启动状态

mysql> show slave status\G;
*************************** 1. row ***************************Slave_IO_State: Master_Host: master1Master_User: repMaster_Port: 3306Connect_Retry: 60Master_Log_File: localhost-bin.000003Read_Master_Log_Pos: 157Relay_Log_File: server-relay-bin.000004Relay_Log_Pos: 126Relay_Master_Log_File: binlog.000038Slave_IO_Running: NoSlave_SQL_Running: YesReplicate_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: 126Relay_Log_Space: 337Until_Condition: NoneUntil_Log_File: Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_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: NoLast_IO_Errno: 13114Last_IO_Error: Got fatal error 1236 from source when reading data from binary log: 'Could not find first log file name in binary log index file'Last_SQL_Errno: 0Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 1Master_UUID: d5ddcb15-d063-11ee-a4cc-000c2904e4beMaster_Info_File: mysql.slave_master_infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Replica has read all relay log; waiting for more updatesMaster_Retry_Count: 86400Master_Bind: Last_IO_Error_Timestamp: 240222 16:42:23Last_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, 1 warning (0.00 sec)ERROR: 
No query specified

此时，发生报错 Last_IO_Error: Got fatal error 1236 from source when reading data from binary log: 'Could not find first log file name in binary log index file'；

解决方案

到从服务器输入
mysql> stop slave-> ;
到master机器登陆mysql：记录master的bin的位置，例如：mysql> show master status;
mysql> show master status;
+--------------------+----------+--------------+------------------+-------------------+
| File               | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+--------------------+----------+--------------+------------------+-------------------+
| service-bin.000004 |      157 |              |                  |                   |
+--------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
必要时使用flush log;进行刷新
到从数据库修改：mysql> stop slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)mysql> change master to master_log_file='service-bin.000004',master_log_pos=157;
Query OK, 0 rows affected, 3 warnings (0.01 sec)mysql> change master to master_host='master1',master_user='rep',master_password='Wyxbuke00.',master_log_file='service-bin.000004';
Query OK, 0 rows affected, 8 warnings (0.02 sec)mysql> start slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)mysql> show slave status\G;
*************************** 1. row ***************************Slave_IO_State: Waiting for source to send eventMaster_Host: master1Master_User: repMaster_Port: 3306Connect_Retry: 60Master_Log_File: service-bin.000004Read_Master_Log_Pos: 157Relay_Log_File: server-relay-bin.000002Relay_Log_Pos: 328Relay_Master_Log_File: service-bin.000004Slave_IO_Running: YesSlave_SQL_Running: YesReplicate_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: 157Relay_Log_Space: 539Until_Condition: NoneUntil_Log_File: Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_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: NoLast_IO_Errno: 0Last_IO_Error: Last_SQL_Errno: 0Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 1Master_UUID: d5ddcb15-d063-11ee-a4cc-000c2904e4beMaster_Info_File: mysql.slave_master_infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Replica has read all relay log; waiting for more updatesMaster_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, 1 warning (0.00 sec)
问题解决！

返回主服务器（master1）更新数据，在从服务器（slave1）观察是否同步。

主服务器添加数据
mysql> insert into master1db.master1tab values (55555);
Query OK, 1 row affected (0.00 sec)
从服务器查看数据是否同步
mysql> select * from master1db.master1tab;
+-------+
| name  |
+-------+
| 1111  |
| 2222  |
| 55555 |
+-------+
3 rows in set (0.00 sec)