我的sql我做主！Mysql 的集群架构详解之组从复制、半同步模式、MGR、Mysql路由和MHA管理集群组

[Mysql 集群技术](#Mysql 集群技术)
- [一、Mysql 在服务器中的部署方法](#一、Mysql 在服务器中的部署方法)
- - [1.1 在Linux下部署mysql](#1.1 在Linux下部署mysql)
  - - [1.1.1 安装依赖性：](#1.1.1 安装依赖性：)
    - [1.1.2 下载并解压源码包](#1.1.2 下载并解压源码包)
    - [1.1.3 源码编译安装mysql](#1.1.3 源码编译安装mysql)
    - [1.1.4 部署mysql](#1.1.4 部署mysql)
- 二、Mysql的组从复制
- - [2.1 配置mastesr](#2.1 配置mastesr)
  - [2.2 配置salve](#2.2 配置salve)
  - [2.3 当有数据时添加slave2](#2.3 当有数据时添加slave2)
  - [2.4 延迟复制](#2.4 延迟复制)
  - [2.5 慢查询日志](#2.5 慢查询日志)
  - [2.6 mysql的并行复制](#2.6 mysql的并行复制)
- 三、半同步模式
- - 3.1半同步模式原理
  - [3.2 gtid模式](#3.2 gtid模式)
  - [3.3 启用半同步模式](#3.3 启用半同步模式)
  - [3.4 测试](#3.4 测试)
- 四、Mysql高可用之组复制 (MGR)
- - [4.1 组复制流程](#4.1 组复制流程)
  - [4.2 组复制单主和多主模式](#4.2 组复制单主和多主模式)
  - 4.3.实现mysql组复制
- 五、Mysql-router（Mysql路由）
- 六、Mysql高可用之MHA
- - [6.2 MHA部署实施](#6.2 MHA部署实施)
  - - [6.2.1 搭建一主两从架构](#6.2.1 搭建一主两从架构)
    - [6.2.2 安装MHA所需要的软件](#6.2.2 安装MHA所需要的软件)
    - [6.2.3 配置MHA 的管理环境](#6.2.3 配置MHA 的管理环境)
    - [6.2.3 MHA的故障切换](#6.2.3 MHA的故障切换)
    - [6.2.3 为MHA添加VIP功能](#6.2.3 为MHA添加VIP功能)

Mysql 集群技术

一、Mysql 在服务器中的部署方法

在企业中90%的服务器操作系统均为Linux

在企业中对于Mysql的安装通常用源码编译的方式来进行

官网：http://www.mysql.com

1.1 在Linux下部署mysql

1.1.1 安装依赖性：

bash 复制代码

[root@mysql-node1 ~]# yum install cmake gcc-c++ openssl-devel ncurses-devel.x86_64 libtirpc-devel-1.3.3-8.el9_4.x86_64.rpm  rpcgen.x86_64 -y 
#rpcgen rhel9版本需要下，7不需要

1.1.2 下载并解压源码包

bash 复制代码

[root@mysql-node1 ~]# tar zxf mysql-boost-5.7.44.tar.gz
[root@mysql-node1 ~]# cd /root/mysql-5.7.44

1.1.3 源码编译安装mysql

bash 复制代码

[root@mysql-node1 mysql-5.7.44]# cmake \
> -DCMAKE_INSTALL_PREFIX=/usr/local/mysql \				#指定安装路径
> -DMYSQL_DATADIR=/data/mysql \							#指定数据目录
> -DMYSQL_UNIX_ADDR=/data/mysql/mysql.sock \			#指定套接字文件
> -DWITH_INNOBASE_STORAGE_ENGINE=1 \					#指定启用INNODB存储引擎，默认用myisam
> -DWITH_EXTRA_CHARSETS=all \							#扩展字符集
> -DDEFAULT_CHARSET=utf8mb4 \							#指定默认字符集
> -DDEFAULT_COLLATION=utf8mb4_unicode_ci \				#指定默认校验字符集
> -DWITH_BOOST=/root/mysql-5.7.44/boost/boost_1_59_0/	#指定c++库依赖

bash 复制代码

[root@mysql-node1 mysql-5.7.44]# make -j4 				#-j4 表示有几个核心就跑几个进程
[root@mysql-node1 mysql-5.7.44# make install

注意：当cmake出错后如果想重新检测，删除 mysql-5.7.44 中 CMakeCache.txt即可

1.1.4 部署mysql

配置环境

bash 复制代码

[root@mysql-node1 ~]# useradd -s /sbin/nologin -M mysql
[root@mysql-node1 ~]# mkdir /data/mysql -p
[root@mysql-node1 ~]# chown mysql.mysql -R /data/mysql/

生成启动脚本

bash 复制代码

[root@mysql-node1 ~]# cd /usr/local/mysql/support-files/
[root@mysql-node1 support-files]# cp mysql.server /etc/init.d/mysqld

生成配置文件

bash 复制代码

[root@mysql-node1 support-files]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql						#指定数据目录
socket=/data/mysql/mysql.sock			#指定套接字
symbolic-links=0						#数据只能存放到数据目录中，禁止链接到数据目录

修改环境变量

bash 复制代码

[root@mysql-node1 support-files]# vim ~/.bash_profile
.....
PATH=$PATH:$HOME/bin:/usr/local/mysql/bin
[root@mysql-node1 support-files]# source ~/.bash_profile

数据库初始化建立mysql基本数据

bash 复制代码

[root@mysql-node1 ~]# mysqld --user mysql --initialize		#注意：记住初始密码
[root@mysql-node1 ~]# /etc/init.d/mysqld start
Starting MySQL.Logging to '/data/mysql/mysql-node1.err'.
 SUCCESS! 
[root@mysql-node1 ~]# chkconfig mysqld on
[root@mysql-node1 ~]# chkconfig --list
.....
mysqld         	0:关	1:关	2:开	3:开	4:开	5:开	6:关

数据库安全初始化

bash 复制代码

[root@mysql-node1 ~]# mysql_secure_installation 

Securing the MySQL server deployment.

Enter password for user root: 					#输入当前密码

New password: 									#输入新密码

Re-enter new password: 							#重复密码

Press y|Y for Yes, any other key for No: no		#是否启用密码插件
Using existing password for root.
Change the password for root ? ((Press y|Y for Yes, any other key for No) : no	#是否要重置密码

Remove anonymous users? (Press y|Y for Yes, any other key for No) : y
Success.

Disallow root login remotely? (Press y|Y for Yes, any other key for No) : y
Success.

Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y

Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y
Success.

测试

bash 复制代码

[root@mysql-node1 ~]# mysql -uroot -predhat
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.7.44 Source distribution

Copyright (c) 2000, 2023, Oracle and/or its affiliates.

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)

二、Mysql的组从复制

2.1 配置mastesr

bash 复制代码

[root@mysql-node1 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
log-bin=mysql-bin
server-id=1

[root@mysql-node1 ~]# /etc/init.d/mysqld restart
Shutting down MySQL.. SUCCESS! 
Starting MySQL. SUCCESS!

进入数据库配置用户权限

bash 复制代码

[root@mysql-node1 ~]# mysql -predhat

mysql> CREATE USER 'repl'@'%' IDENTIFIED BY 'redhat';	#生成专门用来做复制的用户，此用户是用于slave端做认证用
Query OK, 0 rows affected (0.00 sec)

mysql> GRANT REPLICATION SLAVE ON *.* TO repl@'%';		#对这个用户进行授权
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW MASTER STATUS;								#查看master的状态
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 |      595 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

bash 复制代码

[root@mysql-node1 mysql]# mysqlbinlog mysql-bin.000001 -vv		#查看二进制日志
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
.....

2.2 配置salve

bash 复制代码

[root@mysql-node2 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
server-id=2

[root@mysql-node2 ~]# /etc/init.d/mysqld restart
Shutting down MySQL.. SUCCESS! 
Starting MySQL. SUCCESS!

进入数据库配置

bash 复制代码

[root@mysql-node2 ~]# mysql -predhat

mysql> CHANGE MASTER TO MASTER_HOST='172.25.254.10',MASTER_USER='repl',MASTER_PASSWORD='redhat',MASTER_LOG_FILE='mysql-bin.000001',MASTER_LOG_POS=595;
Query OK, 0 rows affected, 2 warnings (0.00 sec)

mysql> START SLAVE;
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW SLAVE STATUS\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 172.25.254.10
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 595
               Relay_Log_File: mysql-node2-relay-bin.000002
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000001
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
......

测试

在master中创建库表添加数据

bash 复制代码

[root@mysql-node1 ~]# mysql -uroot -predhat

mysql> create database zty;
Query OK, 1 row affected (0.00 sec)

mysql> create table zty.userlist (
    -> username varchar(10) not null,
    -> password varchar(50) not null
    -> );
Query OK, 0 rows affected (0.02 sec)

mysql> insert into zty.userlist value ('zty','123');
Query OK, 1 row affected (0.03 sec)

mysql> select * from zty.userlist;
+----------+----------+
| username | password |
+----------+----------+
| zty      | 123      |
+----------+----------+
1 row in set (0.00 sec)

在slave中查看数据是否有同步过来

bash 复制代码

[root@mysql-node2 ~]# mysql -predhat

mysql> select * from zty.userlist;
+----------+----------+
| username | password |
+----------+----------+
| zty      | 123      |
+----------+----------+
1 row in set (0.00 sec)

2.3 当有数据时添加slave2

完成基础配置

bash 复制代码

[root@mysql-node3 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
server-id=3

[root@mysql-node3 ~]# /etc/init.d/mysqld restart

从master节点备份数据

bash 复制代码

[root@mysql-node1 ~]# mysqldump -uroot -predhat zty > zty.sql

注意：

生产环境中备份时需要锁表，保证备份前后的数据一致

mysql> FLUSH TABLES WITH READ LOCK;

备份后再解锁

mysql> UNLOCK TABLES;

mysqldump命令备份的数据文件，在还原时先DROP TABLE，需要合并数据时需要删除此语句
mysql 复制代码
--
-- Table structure for table `userlist`
--
DROP TABLE IF EXISTS `userlist`; #需要合并数据时需要删除此语句
/*!40101 SET @saved_cs_client     = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;

利用master节点中备份出来的zty.sql在slave2中拉平数据

bash 复制代码

[root@mysql-node1 ~]# scp zty.sql root@172.25.254.30:/mnt

bash 复制代码

[root@mysql-node3 support-files]# cd /mnt/
[root@mysql-node3 mnt]# mysql -uroot -predhat -e "create database zty;"
[root@mysql-node3 mnt]# mysql -uroot -predhat zty < zty.sql 
[root@mysql-node3 mnt]# mysql -uroot -predhat -e "select * from zty.userlist;"
+----------+----------+
| username | password |
+----------+----------+
| zty      | 123      |
+----------+----------+

在master中查询日志pos

bash 复制代码

[root@mysql-node1 ~]# mysql -uroot -predhat -e"SHOW MASTER STATUS;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 |     1238 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+

配置slave2的slave功能

bash 复制代码

[root@mysql-node3 ~]# mysql -uroot -predhat

mysql> CHANGE MASTER TO MASTER_HOST='172.25.254.10',MASTER_USER='repl',MASTER_PASSWORD='redhat',MASTER_LOG_FILE='mysql-bin.000001',MASTER_LOG_POS=1238;
Query OK, 0 rows affected, 2 warnings (0.01 sec)

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

mysql> SHOW SLAVE STATUS\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 172.25.254.10
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 1238
               Relay_Log_File: mysql-node3-relay-bin.000002
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000001
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
......

测试：

bash 复制代码

[root@mysql-node1 ~]# mysql -uroot -predhat -e "INSERT INTO zty.userlist VALUES('user1','123');"

[root@mysql-node2 ~]# mysql -uroot -predhat -e 'select * from zty.userlist;'
mysql: [Warning] Using a password on the command line interface can be insecure.
+----------+----------+
| username | password |
+----------+----------+
| zty      | 123      |
| user1    | 123      |
+----------+----------+

[root@mysql-node3 ~]# mysql -uroot -predhat -e 'select * from zty.userlist;'
mysql: [Warning] Using a password on the command line interface can be insecure.
+----------+----------+
| username | password |
+----------+----------+
| zty      | 123      |
| user1    | 123      |
+----------+----------+

2.4 延迟复制

延迟复制时用来控制sql线程的，和i/o线程无关

这个延迟复制不是i/o线程过段时间来复制，i/o是正常工作的

是日志已经保存在slave端了，那个sql要等多久进行回放

在slave端

bash 复制代码

[root@mysql-node3 ~]# mysql -uroot -predhat

mysql> STOP SLAVE SQL_THREAD;
Query OK, 0 rows affected (0.00 sec)

mysql> CHANGE MASTER TO MASTER_DELAY=60;
Query OK, 0 rows affected (0.00 sec)

mysql> START SLAVE SQL_THREAD;
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW SLAVE STATUS\G;
......
			 Master_Server_Id: 1
                  Master_UUID: 843a890a-602f-11ef-b0ba-000c296d3bac
             Master_Info_File: /data/mysql/master.info
                    SQL_Delay: 60		#延迟效果
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
......

在master中写入数据后过了延迟时间才能被查询到

2.5 慢查询日志

慢查询，顾名思义，执行很慢的查询

当执行SQL超过long_query_time参数设定的时间阈值（默认10s）时，就被认为是慢查询，这个SQL语句就是需要优化的

慢查询被记录在慢查询日志里

慢查询日志默认是不开启的

如果需要优化SQL语句，就可以开启这个功能，它可以让你很容易地知道哪些语句是需要优化的。

bash 复制代码

mysql> SHOW variables like "slow%";
+---------------------+----------------------------------+
| Variable_name       | Value                            |
+---------------------+----------------------------------+
| slow_launch_time    | 2                                |
| slow_query_log      | OFF                              |
| slow_query_log_file | /data/mysql/mysql-node1-slow.log |
+---------------------+----------------------------------+
3 rows in set (0.00 sec)

开启慢查询日志

bash 复制代码

[root@mysql-node1 ~]# mysql -uroot -predhat

mysql> SET GLOBAL slow_query_log=ON;
Query OK, 0 rows affected (0.00 sec)

mysql> SET long_query_time=4;
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW VARIABLES like "long%";
+-----------------+----------+
| Variable_name   | Value    |
+-----------------+----------+
| long_query_time | 4.000000 |
+-----------------+----------+
1 row in set (0.00 sec)

mysql> SHOW VARIABLES like "slow%";
+---------------------+----------------------------------+
| Variable_name       | Value                            |
+---------------------+----------------------------------+
| slow_launch_time    | 2                                |
| slow_query_log      | ON                               |		#慢查询日志开启
| slow_query_log_file | /data/mysql/mysql-node1-slow.log |
+---------------------+----------------------------------+
3 rows in set (0.00 sec)

慢查询日志

bash 复制代码

[root@mysql-node1 ~]# cat /data/mysql/mysql-node1-slow.log
/usr/local/mysql/bin/mysqld, Version: 5.7.44-log (Source distribution). started with:
Tcp port: 3306  Unix socket: /data/mysql/mysql.sock
Time                 Id Command    Argument

测试慢查询

bash 复制代码

[root@mysql-node1 ~]# mysql -uroot -predhat

mysql> select sleep(10);
+-----------+
| sleep(10) |
+-----------+
|         0 |
+-----------+
1 row in set (10.01 sec)

[root@mysql-node1 ~]# cat /data/mysql/mysql-node1-slow.log
/usr/local/mysql/bin/mysqld, Version: 5.7.44-log (Source distribution). started with:
Tcp port: 3306  Unix socket: /data/mysql/mysql.sock
Time                 Id Command    Argument
# Time: 2024-08-22T07:35:29.178601Z
# User@Host: root[root] @ localhost []  Id:    11
# Query_time: 10.000675  Lock_time: 0.000000 Rows_sent: 1  Rows_examined: 0
SET timestamp=1724312129;
select sleep(10);

2.6 mysql的并行复制

查看slave中的线程信息

bash 复制代码

mysql> show processlist;
+----+-------------+-----------+------+---------+-------+--------------------------------------------------------+------------------+
| Id | User        | Host      | db   | Command | Time  | State                                                  | Info             |
+----+-------------+-----------+------+---------+-------+--------------------------------------------------------+------------------+
|  3 | system user |           | NULL | Connect | 14439 | Waiting for master to send event                       | NULL             |
|  4 | system user |           | NULL | Connect |   872 | Slave has read all relay log; waiting for more updates | NULL             |
|  6 | root        | localhost | NULL | Query   |     0 | starting                                               | show processlist |
+----+-------------+-----------+------+---------+-------+--------------------------------------------------------+------------------+
3 rows in set (0.00 sec)

默认情况下slave中使用的是sql单线程回放

在master中时多用户读写，如果使用sql单线程回放那么会造成组从延迟严重

开启MySQL的多线程回放可以解决上述问题

在slaves中设定

bash 复制代码

[root@mysql-node2 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
server-id=2
gtid_mode=ON
enforce-gtid-consistency=ON	

slave-parallel-type=LOGICAL_CLOCK		#基于组提交
slave-parallel-workers=16				#开启线程数量
master_info_repository=TABLE			#master信息在表中记录，默认记录在/data/mysql//master.info
relay_log_info_repository=TABLE			#回放日志信息在表中记录，默认记录在/data/mysql/relay-log.info
relay_log_recovery=ON					#日志回放恢复功能开启

[root@mysql-node2 ~]# /etc/init.d/mysqld restart

测试

重新查看slave中的线程信息

此时sql线程转化为协调线程，16个worker负责处理sql协调线程发送过来的处理请求

MySQL 组提交（Group commit）是一个性能优化特性，它允许在一个事务日志同步操作中将多个事务的日志记录一起写入。这样做可以减少磁盘I/O的次数，从而提高数据库的整体性能。

三、半同步模式

3.1半同步模式原理

1.用户线程写入完成后master中的dump会把日志推送到slave端

2.slave中的io线程接收后保存到relaylog中继日志

3.保存完成后slave向master端返回ack

4.在未接受到slave的ack时master端时不做提交的，一直处于等待当收到ack后提交到存储引擎

5.在5.6版本中用到的时after_commit模式，after_commit模式时先提交在等待ack返回后输出ok

3.2 gtid模式

当为启用gtid时我们要考虑的问题

在master端的写入时多用户读写，在slave端的复制时单线程日志回放，所以slave端一定会延迟与master端

这种延迟在slave端的延迟可能会不一致，当master挂掉后slave接管，一般会挑选一个和master延迟日志最接近的充当新的master

那么为接管master的主机继续充当slave角色并会指向到新的master上，作为其slave

这时候按照之前的配置我们需要知道新的master上的pos的id，但是我们无法确定新的master和slave之间差多少

当激活GITD之后

当master出现问题后，slave2和master的数据最接近，会被作为新的master

slave1指向新的master，但是他不会去检测新的master的pos id，只需要继续读取自己gtid_next即可

bash 复制代码

[root@mysql-node1 ~]# mysqlbinlog -vv /data/mysql/mysql-bin.000002 
......
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;
......

bash 复制代码

mysql> select * from mysql.gtid_executed;
+--------------------------------------+----------------+--------------+
| source_uuid                          | interval_start | interval_end |
+--------------------------------------+----------------+--------------+
| 843a890a-602f-11ef-b0ba-000c296d3bac |              1 |            1 |
| 843a890a-602f-11ef-b0ba-000c296d3bac |              2 |            2 |
+--------------------------------------+----------------+--------------+
2 rows in set (0.00 sec)

设置gtid

在master端和slave端开启gtid模式

bash 复制代码

[root@mysql-node1 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
log-bin=mysql-bin
server-id=1
gtid_mode=ON
enforce-gtid-consistency=ON

[root@mysql-node1 ~]# /etc/init.d/mysqld restart

bash 复制代码

[root@mysql-node2 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
log-bin=mysql-bin
server-id=2
gtid_mode=ON
enforce-gtid-consistency=ON

[root@mysql-node2 ~]# /etc/init.d/mysqld restart

bash 复制代码

[root@mysql-node3 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
log-bin=mysql-bin
server-id=3
gtid_mode=ON
enforce-gtid-consistency=ON

[root@mysql-node3 ~]# /etc/init.d/mysqld restart

停止slave端

bash 复制代码

[root@mysql-node2 ~]# /etc/init.d/mysqld restart
mysql> stop slave;
Query OK, 0 rows affected (0.00 sec)

[root@mysql-node3 ~]# /etc/init.d/mysqld restart
mysql> stop slave;
Query OK, 0 rows affected (0.00 sec)

开启slave端的gtid

bash 复制代码

mysql> CHANGE MASTER TO MASTER_HOST='172.25.254.10', MASTER_USER='repl', MASTER_PASSWORD='redhat', MASTER_AUTO_POSITION=1;
Query OK, 0 rows affected, 2 warnings (0.00 sec)

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

mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 172.25.254.10
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000002
          Read_Master_Log_Pos: 154
               Relay_Log_File: mysql-node2-relay-bin.000002
                Relay_Log_Pos: 367
        Relay_Master_Log_File: mysql-bin.000002
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
 ...... 
            Executed_Gtid_Set: 
                Auto_Position: 1		#功能开启
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)

3.3 启用半同步模式

在master端配置启用半同步模式

安装半同步插件

bash 复制代码

[root@mysql-node1 ~]# mysql -uroot -predhat

mysql> INSTALL PLUGIN rpl_semi_sync_master SONAME 'semisync_master.so';
Query OK, 0 rows affected (0.01 sec)

mysql> SELECT PLUGIN_NAME, PLUGIN_STATUS		#查看插件情况
    -> FROM INFORMATION_SCHEMA.PLUGINS
    -> WHERE PLUGIN_NAME LIKE '%semi%';
+----------------------+---------------+
| PLUGIN_NAME          | PLUGIN_STATUS |
+----------------------+---------------+
| rpl_semi_sync_master | ACTIVE        |
+----------------------+---------------+
1 row in set (0.00 sec)

开启半同步功能

bash 复制代码

mysql> SET GLOBAL rpl_semi_sync_master_enabled = 1;
Query OK, 0 rows affected (0.00 sec)

永久开启

bash 复制代码

[root@mysql-node1 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
log-bin=mysql-bin
server-id=1
gtid_mode=ON
enforce-gtid-consistency=ON
rpl_semi_sync_master_enabled=1 		#开启半同步功能

查看半同步功能状态

bash 复制代码

mysql> SHOW VARIABLES LIKE 'rpl_semi_sync%';
+-------------------------------------------+------------+
| Variable_name                             | Value      |
+-------------------------------------------+------------+
| rpl_semi_sync_master_enabled              | ON         |
| rpl_semi_sync_master_timeout              | 10000      |
| rpl_semi_sync_master_trace_level          | 32         |
| rpl_semi_sync_master_wait_for_slave_count | 1          |
| rpl_semi_sync_master_wait_no_slave        | ON         |
| rpl_semi_sync_master_wait_point           | AFTER_SYNC |
+-------------------------------------------+------------+
6 rows in set (0.00 sec)

mysql> SHOW STATUS LIKE 'Rpl_semi_sync%';
+--------------------------------------------+-------+
| Variable_name                              | Value |
+--------------------------------------------+-------+
| Rpl_semi_sync_master_clients               | 0     |
| Rpl_semi_sync_master_net_avg_wait_time     | 0     |
| Rpl_semi_sync_master_net_wait_time         | 0     |
| Rpl_semi_sync_master_net_waits             | 0     |
| Rpl_semi_sync_master_no_times              | 0     |
| Rpl_semi_sync_master_no_tx                 | 0     |
| Rpl_semi_sync_master_status                | ON    |
| Rpl_semi_sync_master_timefunc_failures     | 0     |
| Rpl_semi_sync_master_tx_avg_wait_time      | 0     |
| Rpl_semi_sync_master_tx_wait_time          | 0     |
| Rpl_semi_sync_master_tx_waits              | 0     |
| Rpl_semi_sync_master_wait_pos_backtraverse | 0     |
| Rpl_semi_sync_master_wait_sessions         | 0     |
| Rpl_semi_sync_master_yes_tx                | 0     |
+--------------------------------------------+-------+
14 rows in set (0.01 sec)

在slave端开启半同步功能

bash 复制代码

[root@mysql-node2 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
log-bin=mysql-bin
server-id=2
gtid_mode=ON
enforce-gtid-consistency=ON
rpl_semi_sync_slave_enabled=1 		#开启半同步功能

[root@mysql-node2 ~]# mysql -uroot -predhat
mysql> INSTALL PLUGIN rpl_semi_sync_slave SONAME 'semisync_slave.so';
Query OK, 0 rows affected (0.00 sec)

mysql> SET GLOBAL rpl_semi_sync_slave_enabled =1;
Query OK, 0 rows affected (0.00 sec)

重启io线程，半同步才能生效

bash 复制代码

mysql> STOP SLAVE IO_THREAD;
Query OK, 0 rows affected (0.00 sec)

mysql> START SLAVE IO_THREAD;
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW VARIABLES LIKE 'rpl_semi_sync%';
+---------------------------------+-------+
| Variable_name                   | Value |
+---------------------------------+-------+
| rpl_semi_sync_slave_enabled     | ON    |
| rpl_semi_sync_slave_trace_level | 32    |
+---------------------------------+-------+
2 rows in set (0.00 sec)

mysql> SHOW STATUS LIKE 'Rpl_semi_sync%';
+----------------------------+-------+
| Variable_name              | Value |
+----------------------------+-------+
| Rpl_semi_sync_slave_status | ON    |
+----------------------------+-------+
1 row in set (0.00 sec)

3.4 测试

在master端写入数据

bash 复制代码

[root@mysql-node1 ~]# mysql -uroot -predhat
mysql> insert into zty.userlist values ('user4','123');
Query OK, 1 row affected (0.02 sec)

mysql> SHOW STATUS LIKE 'Rpl_semi_sync%';
+--------------------------------------------+-------+
| Variable_name                              | Value |
+--------------------------------------------+-------+
| Rpl_semi_sync_master_clients               | 1     |
| Rpl_semi_sync_master_net_avg_wait_time     | 0     |
| Rpl_semi_sync_master_net_wait_time         | 0     |
| Rpl_semi_sync_master_net_waits             | 1     |
| Rpl_semi_sync_master_no_times              | 0     |
| Rpl_semi_sync_master_no_tx                 | 0     |			#未同步数据0笔
| Rpl_semi_sync_master_status                | ON    |
| Rpl_semi_sync_master_timefunc_failures     | 0     |
| Rpl_semi_sync_master_tx_avg_wait_time      | 704   |
| Rpl_semi_sync_master_tx_wait_time          | 704   |
| Rpl_semi_sync_master_tx_waits              | 1     |
| Rpl_semi_sync_master_wait_pos_backtraverse | 0     |
| Rpl_semi_sync_master_wait_sessions         | 0     |
| Rpl_semi_sync_master_yes_tx                | 1     |			#已同步数据1笔
+--------------------------------------------+-------+
14 rows in set (0.01 sec)

模拟故障：

在slave端

bash 复制代码

[root@mysql-node2 ~]# mysql -predhat
mysql> STOP SLAVE IO_THREAD;
Query OK, 0 rows affected (0.00 sec)

[root@mysql-node3 ~]# mysql -predhat
mysql> STOP SLAVE IO_THREAD;
Query OK, 0 rows affected (0.00 sec)

在master端插入数据后

bash 复制代码

mysql> insert into zty.userlist values ('user6','666');
Query OK, 1 row affected (10.00 sec)					#10秒超时

mysql> SHOW STATUS LIKE 'Rpl_semi%';
+--------------------------------------------+-------+
| Variable_name                              | Value |
+--------------------------------------------+-------+
| Rpl_semi_sync_master_clients               | 0     |
| Rpl_semi_sync_master_net_avg_wait_time     | 0     |
| Rpl_semi_sync_master_net_wait_time         | 0     |
| Rpl_semi_sync_master_net_waits             | 2     |
| Rpl_semi_sync_master_no_times              | 1     |
| Rpl_semi_sync_master_no_tx                 | 1     |		#一笔数据为同步
| Rpl_semi_sync_master_status                | OFF   |		#自动转为异步模式，当slave恢复会自动恢复
| Rpl_semi_sync_master_timefunc_failures     | 0     |
| Rpl_semi_sync_master_tx_avg_wait_time      | 704   |
| Rpl_semi_sync_master_tx_wait_time          | 704   |
| Rpl_semi_sync_master_tx_waits              | 1     |
| Rpl_semi_sync_master_wait_pos_backtraverse | 0     |
| Rpl_semi_sync_master_wait_sessions         | 0     |
| Rpl_semi_sync_master_yes_tx                | 1     |
+--------------------------------------------+-------+
14 rows in set (0.01 sec)

四、Mysql高可用之组复制 (MGR)

MySQL Group Replication(简称 MGR )是 MySQL 官方于 2016 年 12 月推出的一个全新的高可用与高扩展的解决方案

组复制是 MySQL 5.7.17 版本出现的新特性，它提供了高可用、高扩展、高可靠的 MySQL 集群服务

MySQL 组复制分单主模式和多主模式，传统的mysql复制技术仅解决了数据同步的问题，

MGR 对属于同一组的服务器自动进行协调。对于要提交的事务，组成员必须就全局事务序列中给定事务的顺序达成一致

提交或回滚事务由每个服务器单独完成，但所有服务器都必须做出相同的决定

如果存在网络分区，导致成员无法达成事先定义的分割策略，则在解决此问题之前系统不会继续进行，这是一种内置的自动裂脑保护机制

MGR由组通信系统( Group Communication System ，GCS ) 协议支持

该系统提供故障检测机制、组成员服务以及安全且有序的消息传递

4.1 组复制流程

首先我们将多个节点共同组成一个复制组，在执行读写（RW）事务的时候，需要通过一致性协议层（Consensus 层）的同意，也就是读写事务想要进行提交，必须要经过组里"大多数人"（对应 Node 节点）的同意，大多数指的是同意的节点数量需要大于（N/2+1），这样才可以进行提交，而不是原发起方一个说了算。而针对只读（RO）事务则不需要经过组内同意，直接提交即可

节点数量不能超过9台

4.2 组复制单主和多主模式

single-primary mode(单写或单主模式)

单写模式 group 内只有一台节点可写可读，其他节点只可以读。当主服务器失败时，会自动选择新的主服务器

multi-primary mode(多写或多主模式)

组内的所有机器都是 primary 节点，同时可以进行读写操作，并且数据是最终一致的。

4.3.实现mysql组复制

为了避免出错，在所有节点中从新生成数据库数据

实验前需要在三台主机都配好本地解析
bash 复制代码
[root@mysql-node1 & 2 & 3~]# vim /etc/hosts
172.25.254.10	mysql-node1
172.25.254.20	mysql-node2
172.25.254.30	mysql-node3

在mysql-node1中

bash 复制代码

[root@mysql-node1 ~]# /etc/init.d/mysqld stop
[root@mysql-node1 ~]# rm -rf /data/mysql/*

编辑主配置文件：

bash 复制代码

[root@mysql-node1 ~]# vim /etc/my.cnf
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
server-id=1 																#配置server唯一标识号
disabled_storage_engines="MyISAM,BLACKHOLE,FEDERATED,ARCHIVE,MEMORY" 		#禁用指定存储引擎
gtid_mode=ON 																#启用全局事件标识
enforce_gtid_consistency=ON 												#强制gtid一致
master_info_repository=TABLE 					#复制事件数据到表中而不记录在数据目录中
relay_log_info_repository=TABLE
binlog_checksum=NONE 							#禁止对二进制日志校验
log_slave_updates=ON 							#打开数据库中继，当slave中sql线程读取日志后也会写入到自己的binlog中
log_bin=binlog 									#重新指定log名称 
binlog_format=ROW 								#使用行日志格式 
plugin_load_add='group_replication.so' 			#加载组复制插件
transaction_write_set_extraction=XXHASH64 		#把每个事件编码为加密散列
group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa" 	#通知插件正式加入或创建的组名名称为uuid格式
group_replication_start_on_boot=off 									#在server启动时不自动启动组复制
group_replication_local_address="172.25.254.10:33061" 					#指定插件接受其他成员的信息端口
group_replication_group_seeds="172.25.254.10:33061,172.25.254.20:33061,172.25.254.30:33061"	
																		#本地地址允许访问成员列表
group_replication_ip_whitelist="172.25.254.0/24,127.0.0.1/8" 			#主机白名单
group_replication_bootstrap_group=off 				#不随系统自启而启动,只在初始成员主机中手动开启
													#需要在两种情况下做设定：1.初始化建组时 2.关闭并重新启动整个组时
group_replication_single_primary_mode=OFF 								#使用多主模式
group_replication_enforce_update_everywhere_checks=ON 					#组同步中有任何改变检测更新
group_replication_allow_local_disjoint_gtids_join=1 					#放弃自己信息以master事件为主

bash 复制代码

[root@mysql-node1 ~]# mysqld --user=mysql --initialize
[root@mysql-node1 ~]# /etc/init.d/mysqld start
[root@mysql-node1 ~]# mysql -uroot -p初始化后生成的密码 -e "alter user root@localhost identified by 'redhat';"

配置sql

bash 复制代码

[root@mysql-node1 ~]# mysql -predhat
mysql> SET SQL_LOG_BIN=0;
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE USER rpl_user@'%' IDENTIFIED BY 'redhat';
Query OK, 0 rows affected (0.00 sec)

mysql> GRANT REPLICATION SLAVE ON *.* TO rpl_user@'%';
Query OK, 0 rows affected (0.00 sec)

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)

mysql> SET SQL_LOG_BIN=1;
Query OK, 0 rows affected (0.00 sec)

mysql> CHANGE MASTER TO MASTER_USER='rpl_user', MASTER_PASSWORD='redhat' FOR CHANNEL     'group_replication_recovery';
Query OK, 0 rows affected, 2 warnings (0.00 sec)

mysql> SET GLOBAL group_replication_bootstrap_group=on;				#用以指定初始成员，值在第一台主机中执行
Query OK, 0 rows affected (0.00 sec)

mysql> START GROUP_REPLICATION;
Query OK, 0 rows affected, 1 warning (2.06 sec)

mysql> SET GLOBAL group_replication_bootstrap_group=off;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+--------------+
| CHANNEL_NAME              | MEMBER_ID                            | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE |
+---------------------------+--------------------------------------+-------------+-------------+--------------+
| group_replication_applier | 0df64b11-61cc-11ef-9df3-000c296d3bac | mysql-node1 |        3306 | ONLINE       |
+---------------------------+--------------------------------------+-------------+-------------+--------------+
1 row in set (0.00 sec)

复制配置文件到myql-node2和mysql-node3

bash 复制代码

[root@mysql-node2 ~]# scp /etc/my.cnf root@172.25.254.20:/etc/my.cnf       
                                                                        
[root@mysql-node3 ~]# scp /etc/my.cnf root@172.25.254.30:/etc/my.cnf

修改mysql---node2和mysl-node3中的配置

bash 复制代码

[root@mysql-node2 & 3 ~]# /etc/init.d/mysqld stop
Shutting down MySQL.. SUCCESS! 
[root@mysql-node2 & 3 ~]# rm -rf /data/mysql/*
[root@mysql-node2 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
server-id=2					#在node3上写3
disabled_storage_engines="MyISAM,BLACKHOLE,FEDERATED,ARCHIVE,MEMORY"
gtid_mode=ON
enforce_gtid_consistency=ON
master_info_repository=TABLE
relay_log_info_repository=TABLE
binlog_checksum=NONE
log_slave_updates=ON
log_bin=binlog
binlog_format=ROW
plugin_load_add='group_replication.so'
transaction_write_set_extraction=XXHASH64
group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
group_replication_start_on_boot=off
group_replication_local_address="172.25.254.20:33061"		#在node3上要写30
group_replication_group_seeds="172.25.254.10:33061,172.25.254.20:33061,172.25.254.30:33061"
group_replication_ip_whitelist="172.25.254.0/24,127.0.0.1/8"
group_replication_bootstrap_group=off
group_replication_single_primary_mode=OFF
group_replication_enforce_update_everywhere_checks=ON
group_replication_allow_local_disjoint_gtids_join=1

[root@mysql-node2 & 3 ~]# mysqld --user=mysql --initialize
[root@mysql-node2 & 3 ~]# /etc/init.d/mysqld start
[root@mysql-node2 & 3 ~]# mysql -uroot -p初始化后生成的密码 -e "alter user root@localhost identified by 'redhat';"

配置sql

bash 复制代码

[root@mysql-node2 & 3 ~]# mysql -predhat
mysql> SET SQL_LOG_BIN=0;
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE USER rpl_user@'%' IDENTIFIED BY 'redhat';
Query OK, 0 rows affected (0.00 sec)

mysql> GRANT REPLICATION SLAVE ON *.* TO rpl_user@'%';
Query OK, 0 rows affected (0.00 sec)

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)

mysql> SET SQL_LOG_BIN=1;
Query OK, 0 rows affected (0.00 sec)

mysql> CHANGE MASTER TO MASTER_USER='rpl_user', MASTER_PASSWORD='redhat' FOR CHANNEL 'group_replication_recovery';
Query OK, 0 rows affected, 2 warnings (0.01 sec)

mysql> START GROUP_REPLICATION;
Query OK, 0 rows affected, 1 warning (5.70 sec)

mysql> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+--------------+
| CHANNEL_NAME              | MEMBER_ID                            | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE |
+---------------------------+--------------------------------------+-------------+-------------+--------------+
| group_replication_applier | 0df64b11-61cc-11ef-9df3-000c296d3bac | mysql-node1 |        3306 | ONLINE       |
| group_replication_applier | 7a2299a8-61e5-11ef-9b63-000c29fbe284 | mysql-node2 |        3306 | ONLINE       |
| group_replication_applier | 7d0c3cc3-61e5-11ef-8881-000c29b7a839 | mysql-node3 |        3306 | ONLINE       |
+---------------------------+--------------------------------------+-------------+-------------+--------------+
3 rows in set (0.00 sec)

测试

在每个节点都可以完成读写

在mysql-node1中

bash 复制代码

[root@mysql-node1 ~]# mysql -predhat
mysql> CREATE DATABASE zty;
Query OK, 1 row affected (0.00 sec)

mysql> CREATE TABLE zty.userlist(
    -> username VARCHAR(10) PRIMARY KEY NOT NULL,
    -> password VARCHAR(50) NOT NULL
    -> );
Query OK, 0 rows affected (0.01 sec)

mysql> INSERT INTO zty.userlist VALUES ('user1','111');
Query OK, 1 row affected (0.03 sec)

mysql> SELECT * FROM zty.userlist;
+----------+----------+
| username | password |
+----------+----------+
| user1    | 111      |
+----------+----------+
1 row in set (0.00 sec)

在mysql-node2中

bash 复制代码

[root@mysql-node2 ~]# mysql -predhat
mysql> INSERT INTO zty.userlist values ('user2','222');
Query OK, 1 row affected (0.01 sec)

mysql> SELECT * FROM zty.userlist;
+----------+----------+
| username | password |
+----------+----------+
| user1    | 111      |
| user2    | 222      |
+----------+----------+
2 rows in set (0.00 sec)

在mysql-node3中

bash 复制代码

[root@mysql-node3 ~]# mysql -predhat
mysql> INSERT INTO zty.userlist values ('user3','233');
Query OK, 1 row affected (0.00 sec)

mysql> SELECT * FROM zty.userlist;
+----------+----------+
| username | password |
+----------+----------+
| user1    | 111      |
| user2    | 222      |
| user3    | 233      |
+----------+----------+
3 rows in set (0.00 sec)

五、Mysql-router（Mysql路由）

MySQL Router

是一个对应用程序透明的InnoDB Cluster连接路由服务，提供负载均衡、应用连接故障转移和客户端路由。

利用路由器的连接路由特性，用户可以编写应用程序来连接到路由器，并令路由器使用相应的路由策略来处理连接，使其连接到正确的MySQL数据库服务器

Mysql route的部署方式

安装mysql-router

[root@mysql-node1 ~]# rpm -ivh mysql-router-community-8.4.0-1.el7.x86_64.rpm

配置mysql-router

bash 复制代码

[root@mysql-node1 ~]# vim /etc/mysqlrouter/mysqlrouter.conf 
[routing:ro]
bind_address = 0.0.0.0
bind_port = 7001
destinations = 172.25.254.20:3306,172.25.254.30:3306
routing_strategy = round-robin

[routing:rw]
bind_address = 0.0.0.0
bind_port = 7002
destinations = 172.25.254.30:3306,172.25.254.20:3306
routing_strategy = first-available
[root@mysql-node1 ~]# systemctl start mysqlrouter.service

测试：

在node2、node3建立测试用户

bash 复制代码

mysql> CREATE USER zty@'%' IDENTIFIED BY 'zty';
Query OK, 0 rows affected (0.00 sec)

mysql> GRANT ALL ON *.* TO zty@'%';
Query OK, 0 rows affected (0.00 sec)

查看调度效果

bash 复制代码

[root@mysql-node2 & 3 ~]# watch -n1 lsof -i :3306

bash 复制代码

[root@mysql-node1 ~]# mysql -uzty -pzty -h 172.25.254.10 -P 7001

bash 复制代码

[root@mysql-node2 ~]# watch -n1 lsof -i :3306
COMMAND  PID  USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
mysqld  3509 mysql   30u  IPv6  40384	   0t0  TCP *:mysql (LISTEN)
mysqld  3509 mysql   51u  IPv6  50219	   0t0  TCP mysql-node2:mysql->172.25.254.10:37530 (ESTABLISHED)

再执行一次，可以看到这次访问的是node3

[root@mysql-node1 ~]# mysql -uzty -pzty -h 172.25.254.10 -P 7001

bash 复制代码

[root@mysql-node3 ~]# watch -n1 lsof -i :3306
COMMAND  PID  USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
mysqld  3523 mysql   30u  IPv6  41972	   0t0  TCP *:mysql (LISTEN)
mysqld  3523 mysql   52u  IPv6  32410	   0t0  TCP mysql-node3:mysql->172.25.254.10:42732 (ESTABLISHED)

mysql router 并不能限制数据库的读写，访问分流

六、Mysql高可用之MHA

为什么要用MHA？

Master的单点故障问题

什么是 MHA？

MHA（Master High Availability）是一套优秀的MySQL高可用环境下故障切换和主从复制的软件。
MHA 的出现就是解决MySQL 单点的问题。
MySQL故障切换过程中，MHA能做到0-30秒内自动完成故障切换操作。
MHA能在故障切换的过程中最大程度上保证数据的一致性，以达到真正意义上的高可用。

MHA 的组成

MHA由两部分组成:MHAManager (管理节点) MHA Node (数据库节点),
MHA Manager 可以单独部署在一台独立的机器上管理多个master-slave集群，也可以部署在一台 slave 节点上。
MHA Manager 会定时探测集群中的 master 节点。
当 master 出现故障时，它可以自动将最新数据的 slave 提升为新的 master，然后将所有其他的 slave 重新指向新的 master。

MHA 的特点

自动故障切换过程中，MHA从宕机的主服务器上保存二进制日志，最大程度的保证数据不丢失
使用半同步复制，可以大大降低数据丢失的风险，如果只有一个slave已经收到了最新的二进制日志，MHA可以将最新的二进制日志应用于其他所有的slave服务器上，因此可以保证所有节点的数据一致性
目前MHA支持一主多从架构，最少三台服务，即一主两从

故障切换备选主库的算法

一般判断从库的是从（position/GTID）判断优劣，数据有差异，最接近于master的slave，成为备选主。
数据一致的情况下，按照配置文件顺序，选择备选主库。
设定有权重（candidate_master=1），按照权重强制指定备选主。

1）默认情况下如果一个slave落后master 100M的relay logs的话，即使有权重，也会失效。

2）如果check_repl_delay=0的话，即使落后很多日志，也强制选择其为备选主。

MHA工作原理

目前MHA主要支持一主多从的架构，要搭建MHA,要求一个复制集群必须最少有3台数据库服务器，一主二从，即一台充当Master，台充当备用Master，另一台充当从库。
MHA Node 运行在每台 MySQL 服务器上
MHAManager 会定时探测集群中的master 节点
当master 出现故障时，它可以自动将最新数据的slave 提升为新的master
然后将所有其他的slave 重新指向新的master，VIP自动漂移到新的master。
整个故障转移过程对应用程序完全透明。

6.2 MHA部署实施

实验前需要将各台主机配好本地解析和免密认证

6.2.1 搭建一主两从架构

在master节点中

bash 复制代码

[root@mysql-node1 ~]# /etc/init.d/mysqld stop
Shutting down MySQL.. SUCCESS! 
[root@mysql-node1 ~]# rm -fr /data/mysql/*
[root@mysql-node1 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
server-id=1
log-bin=mysql-bin
gtid_mode=ON
log_slave_updates=ON
enforce-gtid-consistency=ON
symbolic-links=0

[root@mysql-node1 ~]# mysqld --user=mysql --initialize
[root@mysql-node1 ~]# /etc/init.d/mysqld start
[root@mysql-node1 ~]# mysql -uroot -p初始化后生成的密码 -e "alter user root@localhost identified by 'redhat';"

bash 复制代码

[root@mysql-node1 ~]# mysql -uroot -predhat
mysql> alter user root@localhost identified by 'redhat';
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE USER 'repl'@'%' IDENTIFIED BY 'redhat';
Query OK, 0 rows affected (0.00 sec)

mysql> GRANT REPLICATION SLAVE ON *.* TO repl@'%';
Query OK, 0 rows affected (0.01 sec)

mysql> INSTALL PLUGIN rpl_semi_sync_master SONAME 'semisync_master.so';
Query OK, 0 rows affected (0.00 sec)

mysql> SET GLOBAL rpl_semi_sync_master_enabled = 1;
Query OK, 0 rows affected (0.00 sec)

在slave1和slave2中

bash 复制代码

[root@mysql-node2 & 3 ~]# /etc/init.d/mysqld stop
Shutting down MySQL. SUCCESS! 
[root@mysql-node2 & 3 ~]# rm -fr /data/mysql/*
[root@mysql-node2 & 3 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
server-id=2       	#node3写3
log-bin=mysql-bin
gtid_mode=ON
log_slave_updates=ON
enforce-gtid-consistency=ON
symbolic-links=0

[root@mysql-node2 & 3 ~]# mysqld --user=mysql --initialize
[root@mysql-node2 & 3 ~]# /etc/init.d/mysqld start
[root@mysql-node2 & 3 ~]# mysql -uroot -p初始化后生成的密码 -e "alter user root@localhost identified by 'redhat';"

bash 复制代码

[root@mysql-node2 & 3 ~]# mysql -uroot -predhat
mysql> CHANGE MASTER TO MASTER_HOST='172.25.254.10', MASTER_USER='repl', MASTER_PASSWORD='redhat', MASTER_AUTO_POSITION=1;
Query OK, 0 rows affected, 2 warnings (0.00 sec)

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

mysql> INSTALL PLUGIN rpl_semi_sync_slave SONAME 'semisync_slave.so';
Query OK, 0 rows affected (0.00 sec)

mysql> SET GLOBAL rpl_semi_sync_slave_enabled =1;
Query OK, 0 rows affected (0.00 sec)

mysql> STOP SLAVE IO_THREAD;
Query OK, 0 rows affected (0.00 sec)

mysql> START SLAVE IO_THREAD;
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW STATUS LIKE 'Rpl_semi_sync%';
+----------------------------+-------+
| Variable_name              | Value |
+----------------------------+-------+
| Rpl_semi_sync_slave_status | ON    |
+----------------------------+-------+
1 row in set (0.01 sec)

6.2.2 安装MHA所需要的软件

在MHA中

bash 复制代码

[root@mysql-mha ~]# unzip MHA-7.zip  
[root@mysql-mha ~]# cd MHA-7/
[root@mysql-mha MHA-7]# ls
mha4mysql-manager-0.58-0.el7.centos.noarch.rpm  perl-Mail-Sender-0.8.23-1.el7.noarch.rpm
mha4mysql-manager-0.58.tar.gz                   perl-Mail-Sendmail-0.79-21.el7.noarch.rpm
mha4mysql-node-0.58-0.el7.centos.noarch.rpm     perl-MIME-Lite-3.030-1.el7.noarch.rpm
perl-Config-Tiny-2.14-7.el7.noarch.rpm          perl-MIME-Types-1.38-2.el7.noarch.rpm
perl-Email-Date-Format-1.002-15.el7.noarch.rpm  perl-Net-Telnet-3.03-19.el7.noarch.rpm
perl-Log-Dispatch-2.41-1.el7.1.noarch.rpm       perl-Parallel-ForkManager-1.18-2.el7.noarch.rpm
[root@mysql-mha MHA-7]# yum install *.rpm -y
[root@mysql-mha MHA-7]# scp mha4mysql-node-0.58-0.el7.centos.noarch.rpm root@172.25.254.10:/mnt
[root@mysql-mha MHA-7]# scp mha4mysql-node-0.58-0.el7.centos.noarch.rpm root@172.25.254.20:/mnt   
[root@mysql-mha MHA-7]# scp mha4mysql-node-0.58-0.el7.centos.noarch.rpm root@172.25.254.30:/mnt

在sql-node中

bash 复制代码

[root@mysql-node1 & 2 & 3 ~]# yum install /mnt/mha4mysql-node-0.58-0.el7.centos.noarch.rpm -y

在软件中包含的工具包介绍

1.Manager工具包主要包括以下几个工具：

masterha_check_ssh 			#检查MHA的SSH配置状况
masterha_check_repl 		#检查MySQL复制状况 
masterha_manger 			#启动MHA
masterha_check_status 		#检测当前MHA运行状态
masterha_master_monitor 	#检测master是否宕机
masterha_master_switch 		#控制故障转移（自动或者手动）
masterha_conf_host 			#添加或删除配置的server信息

2.Node工具包（通常由masterHA主机直接调用，无需人为执行）

ave_binary_logs 			#保存和复制master的二进制日志
apply_diff_relay_logs 		#识别差异的中继日志事件并将其差异的事件应用于其他的slave
filter_mysqlbinlog 			#去除不必要的ROLLBACK事件（MHA已不再使用这个工具）
purge_relay_logs 			#清除中继日志（不会阻塞SQL线程）

6.2.3 配置MHA 的管理环境

1.生成配置目录和配置文件

bash 复制代码

[root@mysql-mha ~]# masterha_manager --help
Usage:
    masterha_manager --global_conf=/etc/masterha_default.cnf	#全局配置文件，记录公共设定
    --conf=/usr/local/masterha/conf/app1.cnf				#不同管理配置文件，记录各自配置

    See online reference
    (http://code.google.com/p/mysql-master-ha/wiki/masterha_manager) for
    details.

因为我们当前只有一套主从，所以我们只需要写一个配置文件即可

rpm包中没有为我们准备配置文件的模板

可以解压源码包后在samples中找到配置文件的模板文件

生成配置文件

bash 复制代码

[root@mysql-mha MHA-7]# mkdir /etc/masterha
[root@mysql-mha MHA-7]# tar zxf mha4mysql-manager-0.58.tar.gz
[root@mysql-mha MHA-7]# cd mha4mysql-manager-0.58/samples/conf/
[root@mysql-mha conf]#  cat masterha_default.cnf app1.cnf > /etc/masterha/app1.cnf

编辑配置文件

bash 复制代码

[root@mysql-mha conf]# vim /etc/masterha/app1.cnf
[server default]
user=root								#mysql管理员用户，因为需要做自动化配置
password=redhat							#mysql密码
ssh_user=root							#ssh远程登陆用户
repl_user=repl							#mysql主从复制中负责认证的用户
repl_password=redhat					#mysql主从复制中负责认证的用户密码

master_binlog_dir= /data/mysql			#二进制日志目录
remote_workdir=/tmp						#远程工作目录

#此参数使为了提供冗余检测，方式是mha主机网络自身的问题无法连接数据库节点，应为集群之外的主机
secondary_check_script= masterha_secondary_check -s 172.25.254.10 -s 172.25.254.11
ping_interval=3							#每隔3秒检测一次

#发生故障后调用的脚本，用来迁移vip
# master_ip_failover_script= /script/masterha/master_ip_failover

#电源管理脚本
# shutdown_script= /script/masterha/power_manager

#当发生故障后用此脚本发邮件或者告警通知
# report_script= /script/masterha/send_report

#在线切换时调用的vip迁移脚本，手动
# master_ip_online_change_script= /script/masterha/master_ip_online_change

[server default]
manager_workdir=/etc/masterha					#mha工作目录
manager_log=/etc/masterha/manager.log		#mha日志

[server1]
hostname=172.25.254.10
candidate_master=1								#可能作为master的主机
check_repl_delay=0								##默认情况下如果一个slave落后master 100M的relay logs的话
 												#MHA将不会选择该slave作为一个新的master
 												#因为对于这个slave的恢复需要花费很长时间
 												#通过设置check_repl_delay=0
 												#MHA触发切换在选择一个新的master的时候将会忽略复制延时
 												#这个参数对于设置了candidate_master=1的主机非常有用
 												#因为这个候选主在切换的过程中一定是新的master

[server2]
hostname=172.25.254.20
candidate_master=1
check_repl_delay=0

[server3]
hostname=172.25.254.30
no_master=1										#不会作为master的主机

2.检测配置：

a）检测网络及ssh免密

bash 复制代码

[root@mysql-mha ~]# masterha_check_ssh --conf=/etc/masterha/app1.cnf
Sat Aug 24 23:31:48 2024 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sat Aug 24 23:31:48 2024 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Sat Aug 24 23:31:48 2024 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Sat Aug 24 23:31:48 2024 - [info] Starting SSH connection tests..
Sat Aug 24 23:31:48 2024 - [debug] 
Sat Aug 24 23:31:48 2024 - [debug]  Connecting via SSH from root@172.25.254.10(172.25.254.10:22) to root@172.25.254.20(172.25.254.20:22)..
Sat Aug 24 23:31:48 2024 - [debug]   ok.
Sat Aug 24 23:31:48 2024 - [debug]  Connecting via SSH from root@172.25.254.10(172.25.254.10:22) to root@172.25.254.30(172.25.254.30:22)..
Sat Aug 24 23:31:48 2024 - [debug]   ok.
Sat Aug 24 23:31:49 2024 - [debug] 
Sat Aug 24 23:31:48 2024 - [debug]  Connecting via SSH from root@172.25.254.20(172.25.254.20:22) to root@172.25.254.10(172.25.254.10:22)..
Sat Aug 24 23:31:48 2024 - [debug]   ok.
Sat Aug 24 23:31:48 2024 - [debug]  Connecting via SSH from root@172.25.254.20(172.25.254.20:22) to root@172.25.254.30(172.25.254.30:22)..
Sat Aug 24 23:31:49 2024 - [debug]   ok.
Sat Aug 24 23:31:49 2024 - [debug] 
Sat Aug 24 23:31:49 2024 - [debug]  Connecting via SSH from root@172.25.254.30(172.25.254.30:22) to root@172.25.254.10(172.25.254.10:22)..
Sat Aug 24 23:31:49 2024 - [debug]   ok.
Sat Aug 24 23:31:49 2024 - [debug]  Connecting via SSH from root@172.25.254.30(172.25.254.30:22) to root@172.25.254.20(172.25.254.20:22)..
Sat Aug 24 23:31:49 2024 - [debug]   ok.
Sat Aug 24 23:31:49 2024 - [info] All SSH connection tests passed successfully.

b）检测数据主从复制情况

在数据节点master端，允许root远程登陆

bash 复制代码

mysql> GRANT ALL ON *.* TO root@'%' identified by 'redhat';
Query OK, 0 rows affected, 1 warning (0.00 sec)

执行检测

bash 复制代码

[root@mysql-mha ~]# masterha_check_repl --conf=/etc/masterha/app1.cnf
Sat Aug 24 23:35:09 2024 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sat Aug 24 23:35:09 2024 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Sat Aug 24 23:35:09 2024 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Sat Aug 24 23:35:09 2024 - [info] MHA::MasterMonitor version 0.58.
Sat Aug 24 23:35:11 2024 - [info] GTID failover mode = 1
Sat Aug 24 23:35:11 2024 - [info] Dead Servers:
Sat Aug 24 23:35:11 2024 - [info] Alive Servers:
Sat Aug 24 23:35:11 2024 - [info]   172.25.254.10(172.25.254.10:3306)
Sat Aug 24 23:35:11 2024 - [info]   172.25.254.20(172.25.254.20:3306)
Sat Aug 24 23:35:11 2024 - [info]   172.25.254.30(172.25.254.30:3306)
Sat Aug 24 23:35:11 2024 - [info] Alive Slaves:
Sat Aug 24 23:35:11 2024 - [info]   172.25.254.20(172.25.254.20:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sat Aug 24 23:35:11 2024 - [info]     GTID ON
Sat Aug 24 23:35:11 2024 - [info]     Replicating from 172.25.254.10(172.25.254.10:3306)
Sat Aug 24 23:35:11 2024 - [info]     Primary candidate for the new Master (candidate_master is set)
Sat Aug 24 23:35:11 2024 - [info]   172.25.254.30(172.25.254.30:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sat Aug 24 23:35:11 2024 - [info]     GTID ON
Sat Aug 24 23:35:11 2024 - [info]     Replicating from 172.25.254.10(172.25.254.10:3306)
Sat Aug 24 23:35:11 2024 - [info]     Not candidate for the new Master (no_master is set)
Sat Aug 24 23:35:11 2024 - [info] Current Alive Master: 172.25.254.10(172.25.254.10:3306)
Sat Aug 24 23:35:11 2024 - [info] Checking slave configurations..
Sat Aug 24 23:35:11 2024 - [info]  read_only=1 is not set on slave 172.25.254.20(172.25.254.20:3306).
Sat Aug 24 23:35:11 2024 - [info]  read_only=1 is not set on slave 172.25.254.30(172.25.254.30:3306).
Sat Aug 24 23:35:11 2024 - [info] Checking replication filtering settings..
Sat Aug 24 23:35:11 2024 - [info]  binlog_do_db= , binlog_ignore_db= 
Sat Aug 24 23:35:11 2024 - [info]  Replication filtering check ok.
Sat Aug 24 23:35:11 2024 - [info] GTID (with auto-pos) is supported. Skipping all SSH and Node package checking.
Sat Aug 24 23:35:11 2024 - [info] Checking SSH publickey authentication settings on the current master..
Sat Aug 24 23:35:11 2024 - [info] HealthCheck: SSH to 172.25.254.10 is reachable.
Sat Aug 24 23:35:11 2024 - [info] 
172.25.254.10(172.25.254.10:3306) (current master)
 +--172.25.254.20(172.25.254.20:3306)
 +--172.25.254.30(172.25.254.30:3306)

Sat Aug 24 23:35:11 2024 - [info] Checking replication health on 172.25.254.20..
Sat Aug 24 23:35:11 2024 - [info]  ok.
Sat Aug 24 23:35:11 2024 - [info] Checking replication health on 172.25.254.30..
Sat Aug 24 23:35:11 2024 - [info]  ok.
Sat Aug 24 23:35:11 2024 - [warning] master_ip_failover_script is not defined.
Sat Aug 24 23:35:11 2024 - [warning] shutdown_script is not defined.
Sat Aug 24 23:35:11 2024 - [info] Got exit code 0 (Not master dead).

MySQL Replication Health is OK.

6.2.3 MHA的故障切换

MHA的故障切换过程

共包括以下的步骤：

1.配置文件检查阶段，这个阶段会检查整个集群配置文件配置

2.宕机的master处理，这个阶段包括虚拟ip摘除操作，主机关机操作

3.复制dead master和最新slave相差的relay log，并保存到MHA Manger具体的目录下

4.识别含有最新更新的slave

5.应用从master保存的二进制日志事件（binlog events）

6.提升一个slave为新的master进行复制 7.使其他的slave连接新的master进行复制

切换方式：

master未出现故障手动切换

在master数据节点还在正常工作情况下

bash 复制代码

[root@mysql-mha ~]# masterha_master_switch \
> --conf=/etc/masterha/app1.cnf \				#指定配置文件
> --master_state=alive \						#指定master节点状态
> --new_master_host=172.25.254.20 \				#指定新master节点
> --new_master_port=3306 \						#执行新master节点端口
> --orig_master_is_new_slave \					#原始master会变成新的slave
> --running_updates_limit=10000					#切换的超时时间

切换过程如下：

bash 复制代码

Sun Aug 25 10:25:38 2024 - [info] MHA::MasterRotate version 0.58.
Sun Aug 25 10:25:38 2024 - [info] Starting online master switch..
Sun Aug 25 10:25:38 2024 - [info] 
Sun Aug 25 10:25:38 2024 - [info] * Phase 1: Configuration Check Phase..
Sun Aug 25 10:25:38 2024 - [info] 
Sun Aug 25 10:25:38 2024 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sun Aug 25 10:25:38 2024 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Sun Aug 25 10:25:38 2024 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Sun Aug 25 10:25:39 2024 - [info] GTID failover mode = 1
Sun Aug 25 10:25:39 2024 - [info] Current Alive Master: 172.25.254.10(172.25.254.10:3306)
Sun Aug 25 10:25:39 2024 - [info] Alive Slaves:
Sun Aug 25 10:25:39 2024 - [info]   172.25.254.20(172.25.254.20:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 10:25:39 2024 - [info]     GTID ON
Sun Aug 25 10:25:39 2024 - [info]     Replicating from 172.25.254.10(172.25.254.10:3306)
Sun Aug 25 10:25:39 2024 - [info]     Primary candidate for the new Master (candidate_master is set)
Sun Aug 25 10:25:39 2024 - [info]   172.25.254.30(172.25.254.30:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 10:25:39 2024 - [info]     GTID ON
Sun Aug 25 10:25:39 2024 - [info]     Replicating from 172.25.254.10(172.25.254.10:3306)
Sun Aug 25 10:25:39 2024 - [info]     Not candidate for the new Master (no_master is set)

It is better to execute FLUSH NO_WRITE_TO_BINLOG TABLES on the master before switching. Is it ok to execute on 172.25.254.10(172.25.254.10:3306)? (YES/no): yes		###
Sun Aug 25 10:25:47 2024 - [info] Executing FLUSH NO_WRITE_TO_BINLOG TABLES. This may take long time..
Sun Aug 25 10:25:47 2024 - [info]  ok.
Sun Aug 25 10:25:47 2024 - [info] Checking MHA is not monitoring or doing failover..
Sun Aug 25 10:25:47 2024 - [info] Checking replication health on 172.25.254.20..
Sun Aug 25 10:25:47 2024 - [info]  ok.
Sun Aug 25 10:25:47 2024 - [info] Checking replication health on 172.25.254.30..
Sun Aug 25 10:25:47 2024 - [info]  ok.
Sun Aug 25 10:25:47 2024 - [info] 172.25.254.20 can be new master.
Sun Aug 25 10:25:47 2024 - [info] 
From:
172.25.254.10(172.25.254.10:3306) (current master)
 +--172.25.254.20(172.25.254.20:3306)
 +--172.25.254.30(172.25.254.30:3306)

To:
172.25.254.20(172.25.254.20:3306) (new master)
 +--172.25.254.30(172.25.254.30:3306)
 +--172.25.254.10(172.25.254.10:3306)

Starting master switch from 172.25.254.10(172.25.254.10:3306) to 172.25.254.20(172.25.254.20:3306)? (yes/NO): yes    ###
Sun Aug 25 10:25:57 2024 - [info] Checking whether 172.25.254.20(172.25.254.20:3306) is ok for the new master..
Sun Aug 25 10:25:57 2024 - [info]  ok.
Sun Aug 25 10:25:57 2024 - [info] 172.25.254.10(172.25.254.10:3306): SHOW SLAVE STATUS returned empty result. To check replication filtering rules, temporarily executing CHANGE MASTER to a dummy host.
Sun Aug 25 10:25:57 2024 - [info] 172.25.254.10(172.25.254.10:3306): Resetting slave pointing to the dummy host.
Sun Aug 25 10:25:57 2024 - [info] ** Phase 1: Configuration Check Phase completed.
Sun Aug 25 10:25:57 2024 - [info] 
Sun Aug 25 10:25:57 2024 - [info] * Phase 2: Rejecting updates Phase..
Sun Aug 25 10:25:57 2024 - [info] 
master_ip_online_change_script is not defined. If you do not disable writes on the current master manually, applications keep writing on the current master. Is it ok to proceed? (yes/NO): yes		###
Sun Aug 25 10:25:59 2024 - [info] Locking all tables on the orig master to reject updates from everybody (including root):
Sun Aug 25 10:25:59 2024 - [info] Executing FLUSH TABLES WITH READ LOCK..
Sun Aug 25 10:25:59 2024 - [info]  ok.
Sun Aug 25 10:25:59 2024 - [info] Orig master binlog:pos is mysql-bin.000004:194.
Sun Aug 25 10:25:59 2024 - [info]  Waiting to execute all relay logs on 172.25.254.20(172.25.254.20:3306)..
Sun Aug 25 10:25:59 2024 - [info]  master_pos_wait(mysql-bin.000004:194) completed on 172.25.254.20(172.25.254.20:3306). Executed 0 events.
Sun Aug 25 10:25:59 2024 - [info]   done.
Sun Aug 25 10:25:59 2024 - [info] Getting new master's binlog name and position..
Sun Aug 25 10:25:59 2024 - [info]  mysql-bin.000004:234
Sun Aug 25 10:25:59 2024 - [info]  All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST='172.25.254.20', MASTER_PORT=3306, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='xxx';
Sun Aug 25 10:25:59 2024 - [info] 
Sun Aug 25 10:25:59 2024 - [info] * Switching slaves in parallel..
Sun Aug 25 10:25:59 2024 - [info] 
Sun Aug 25 10:25:59 2024 - [info] -- Slave switch on host 172.25.254.30(172.25.254.30:3306) started, pid: 2449
Sun Aug 25 10:25:59 2024 - [info] 
Sun Aug 25 10:26:01 2024 - [info] Log messages from 172.25.254.30 ...
Sun Aug 25 10:26:01 2024 - [info] 
Sun Aug 25 10:25:59 2024 - [info]  Waiting to execute all relay logs on 172.25.254.30(172.25.254.30:3306)..
Sun Aug 25 10:25:59 2024 - [info]  master_pos_wait(mysql-bin.000004:194) completed on 172.25.254.30(172.25.254.30:3306). Executed 0 events.
Sun Aug 25 10:25:59 2024 - [info]   done.
Sun Aug 25 10:25:59 2024 - [info]  Resetting slave 172.25.254.30(172.25.254.30:3306) and starting replication from the new master 172.25.254.20(172.25.254.20:3306)..
Sun Aug 25 10:25:59 2024 - [info]  Executed CHANGE MASTER.
Sun Aug 25 10:26:00 2024 - [info]  Slave started.
Sun Aug 25 10:26:01 2024 - [info] End of log messages from 172.25.254.30 ...
Sun Aug 25 10:26:01 2024 - [info] 
Sun Aug 25 10:26:01 2024 - [info] -- Slave switch on host 172.25.254.30(172.25.254.30:3306) succeeded.
Sun Aug 25 10:26:01 2024 - [info] Unlocking all tables on the orig master:
Sun Aug 25 10:26:01 2024 - [info] Executing UNLOCK TABLES..
Sun Aug 25 10:26:01 2024 - [info]  ok.
Sun Aug 25 10:26:01 2024 - [info] Starting orig master as a new slave..
Sun Aug 25 10:26:01 2024 - [info]  Resetting slave 172.25.254.10(172.25.254.10:3306) and starting replication from the new master 172.25.254.20(172.25.254.20:3306)..
Sun Aug 25 10:26:01 2024 - [info]  Executed CHANGE MASTER.
Sun Aug 25 10:26:02 2024 - [info]  Slave started.
Sun Aug 25 10:26:02 2024 - [info] All new slave servers switched successfully.
Sun Aug 25 10:26:02 2024 - [info] 
Sun Aug 25 10:26:02 2024 - [info] * Phase 5: New master cleanup phase..
Sun Aug 25 10:26:02 2024 - [info] 
Sun Aug 25 10:26:02 2024 - [info]  172.25.254.20: Resetting slave info succeeded.
Sun Aug 25 10:26:02 2024 - [info] Switching master to 172.25.254.20(172.25.254.20:3306) completed successfully.

检测：

bash 复制代码

[root@mysql-mha ~]# masterha_check_repl --conf=/etc/masterha/app1.cnf
......
Sun Aug 25 10:27:39 2024 - [info] Checking replication health on 172.25.254.10..
Sun Aug 25 10:27:39 2024 - [info]  ok.
Sun Aug 25 10:27:39 2024 - [info] Checking replication health on 172.25.254.30..
Sun Aug 25 10:27:39 2024 - [info]  ok.
Sun Aug 25 10:27:39 2024 - [warning] master_ip_failover_script is not defined.
Sun Aug 25 10:27:39 2024 - [warning] shutdown_script is not defined.
Sun Aug 25 10:27:39 2024 - [info] Got exit code 0 (Not master dead).

MySQL Replication Health is OK.

master故障手动切换

模拟master故障

bash 复制代码

[root@mysql-node2 ~]# /etc/init.d/mysqld stop
Shutting down MySQL........... SUCCESS!

在MHA中做故障切换

bash 复制代码

[root@mysql-mha ~]# masterha_master_switch \
> --master_state=dead \
> --conf=/etc/masterha/app1.cnf \
> --dead_master_host=172.25.254.20 \
> --dead_master_port=3306 \
> --new_master_host=172.25.254.10 \
> --new_master_port=3306 \
> --ignore_last_failover			#表示忽略在/etc/masterha/目录中在切换过程中生成的锁文件

bash 复制代码

--dead_master_ip=<dead_master_ip> is not set. Using 172.25.254.20.
Sun Aug 25 10:33:41 2024 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sun Aug 25 10:33:41 2024 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Sun Aug 25 10:33:41 2024 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Sun Aug 25 10:33:41 2024 - [info] MHA::MasterFailover version 0.58.
Sun Aug 25 10:33:41 2024 - [info] Starting master failover.
Sun Aug 25 10:33:41 2024 - [info] 
Sun Aug 25 10:33:41 2024 - [info] * Phase 1: Configuration Check Phase..
Sun Aug 25 10:33:41 2024 - [info] 
Sun Aug 25 10:33:42 2024 - [info] GTID failover mode = 1
Sun Aug 25 10:33:42 2024 - [info] Dead Servers:
Sun Aug 25 10:33:42 2024 - [info]   172.25.254.20(172.25.254.20:3306)
Sun Aug 25 10:33:42 2024 - [info] Checking master reachability via MySQL(double check)...
Sun Aug 25 10:33:42 2024 - [info]  ok.
Sun Aug 25 10:33:42 2024 - [info] Alive Servers:
Sun Aug 25 10:33:42 2024 - [info]   172.25.254.10(172.25.254.10:3306)
Sun Aug 25 10:33:42 2024 - [info]   172.25.254.30(172.25.254.30:3306)
Sun Aug 25 10:33:42 2024 - [info] Alive Slaves:
Sun Aug 25 10:33:42 2024 - [info]   172.25.254.10(172.25.254.10:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 10:33:42 2024 - [info]     GTID ON
Sun Aug 25 10:33:42 2024 - [info]     Replicating from 172.25.254.20(172.25.254.20:3306)
Sun Aug 25 10:33:42 2024 - [info]     Primary candidate for the new Master (candidate_master is set)
Sun Aug 25 10:33:42 2024 - [info]   172.25.254.30(172.25.254.30:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 10:33:42 2024 - [info]     GTID ON
Sun Aug 25 10:33:42 2024 - [info]     Replicating from 172.25.254.20(172.25.254.20:3306)
Sun Aug 25 10:33:42 2024 - [info]     Not candidate for the new Master (no_master is set)
Master 172.25.254.20(172.25.254.20:3306) is dead. Proceed? (yes/NO): yes	###
Sun Aug 25 10:33:45 2024 - [info] Starting GTID based failover.
Sun Aug 25 10:33:45 2024 - [info] 
Sun Aug 25 10:33:45 2024 - [info] ** Phase 1: Configuration Check Phase completed.
Sun Aug 25 10:33:45 2024 - [info] 
Sun Aug 25 10:33:45 2024 - [info] * Phase 2: Dead Master Shutdown Phase..
Sun Aug 25 10:33:45 2024 - [info] 
Sun Aug 25 10:33:45 2024 - [info] HealthCheck: SSH to 172.25.254.20 is reachable.
Sun Aug 25 10:33:45 2024 - [info] Forcing shutdown so that applications never connect to the current master..
Sun Aug 25 10:33:45 2024 - [warning] master_ip_failover_script is not set. Skipping invalidating dead master IP address.
Sun Aug 25 10:33:45 2024 - [warning] shutdown_script is not set. Skipping explicit shutting down of the dead master.
Sun Aug 25 10:33:45 2024 - [info] * Phase 2: Dead Master Shutdown Phase completed.
Sun Aug 25 10:33:45 2024 - [info] 
Sun Aug 25 10:33:45 2024 - [info] * Phase 3: Master Recovery Phase..
Sun Aug 25 10:33:45 2024 - [info] 
Sun Aug 25 10:33:45 2024 - [info] * Phase 3.1: Getting Latest Slaves Phase..
Sun Aug 25 10:33:45 2024 - [info] 
Sun Aug 25 10:33:45 2024 - [info] The latest binary log file/position on all slaves is mysql-bin.000004:234
Sun Aug 25 10:33:45 2024 - [info] Retrieved Gtid Set: 7a6b31af-6228-11ef-bf1c-000c29fbe284:1
Sun Aug 25 10:33:45 2024 - [info] Latest slaves (Slaves that received relay log files to the latest):
Sun Aug 25 10:33:45 2024 - [info]   172.25.254.10(172.25.254.10:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 10:33:45 2024 - [info]     GTID ON
Sun Aug 25 10:33:45 2024 - [info]     Replicating from 172.25.254.20(172.25.254.20:3306)
Sun Aug 25 10:33:45 2024 - [info]     Primary candidate for the new Master (candidate_master is set)
Sun Aug 25 10:33:45 2024 - [info]   172.25.254.30(172.25.254.30:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 10:33:45 2024 - [info]     GTID ON
Sun Aug 25 10:33:45 2024 - [info]     Replicating from 172.25.254.20(172.25.254.20:3306)
Sun Aug 25 10:33:45 2024 - [info]     Not candidate for the new Master (no_master is set)
Sun Aug 25 10:33:45 2024 - [info] The oldest binary log file/position on all slaves is mysql-bin.000004:234
Sun Aug 25 10:33:45 2024 - [info] Retrieved Gtid Set: 7a6b31af-6228-11ef-bf1c-000c29fbe284:1
Sun Aug 25 10:33:45 2024 - [info] Oldest slaves:
Sun Aug 25 10:33:45 2024 - [info]   172.25.254.10(172.25.254.10:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 10:33:45 2024 - [info]     GTID ON
Sun Aug 25 10:33:45 2024 - [info]     Replicating from 172.25.254.20(172.25.254.20:3306)
Sun Aug 25 10:33:45 2024 - [info]     Primary candidate for the new Master (candidate_master is set)
Sun Aug 25 10:33:45 2024 - [info]   172.25.254.30(172.25.254.30:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 10:33:45 2024 - [info]     GTID ON
Sun Aug 25 10:33:45 2024 - [info]     Replicating from 172.25.254.20(172.25.254.20:3306)
Sun Aug 25 10:33:45 2024 - [info]     Not candidate for the new Master (no_master is set)
Sun Aug 25 10:33:45 2024 - [info] 
Sun Aug 25 10:33:45 2024 - [info] * Phase 3.3: Determining New Master Phase..
Sun Aug 25 10:33:45 2024 - [info] 
Sun Aug 25 10:33:45 2024 - [info] 172.25.254.10 can be new master.
Sun Aug 25 10:33:45 2024 - [info] New master is 172.25.254.10(172.25.254.10:3306)
Sun Aug 25 10:33:45 2024 - [info] Starting master failover..
Sun Aug 25 10:33:45 2024 - [info] 
From:
172.25.254.20(172.25.254.20:3306) (current master)
 +--172.25.254.10(172.25.254.10:3306)
 +--172.25.254.30(172.25.254.30:3306)

To:
172.25.254.10(172.25.254.10:3306) (new master)
 +--172.25.254.30(172.25.254.30:3306)

Starting master switch from 172.25.254.20(172.25.254.20:3306) to 172.25.254.10(172.25.254.10:3306)? (yes/NO): yes		###
Sun Aug 25 10:33:47 2024 - [info] New master decided manually is 172.25.254.10(172.25.254.10:3306)
Sun Aug 25 10:33:47 2024 - [info] 
Sun Aug 25 10:33:47 2024 - [info] * Phase 3.3: New Master Recovery Phase..
Sun Aug 25 10:33:47 2024 - [info] 
Sun Aug 25 10:33:47 2024 - [info]  Waiting all logs to be applied.. 
Sun Aug 25 10:33:47 2024 - [info]   done.
Sun Aug 25 10:33:47 2024 - [info] Getting new master's binlog name and position..
Sun Aug 25 10:33:47 2024 - [info]  mysql-bin.000004:438
Sun Aug 25 10:33:47 2024 - [info]  All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST='172.25.254.10', MASTER_PORT=3306, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='xxx';
Sun Aug 25 10:33:47 2024 - [info] Master Recovery succeeded. File:Pos:Exec_Gtid_Set: mysql-bin.000004, 438, 7a6b31af-6228-11ef-bf1c-000c29fbe284:1,
b0a1e6d3-6227-11ef-b421-000c296d3bac:1-4
Sun Aug 25 10:33:47 2024 - [warning] master_ip_failover_script is not set. Skipping taking over new master IP address.
Sun Aug 25 10:33:47 2024 - [info] Setting read_only=0 on 172.25.254.10(172.25.254.10:3306)..
Sun Aug 25 10:33:47 2024 - [info]  ok.
Sun Aug 25 10:33:47 2024 - [info] ** Finished master recovery successfully.
Sun Aug 25 10:33:47 2024 - [info] * Phase 3: Master Recovery Phase completed.
Sun Aug 25 10:33:47 2024 - [info] 
Sun Aug 25 10:33:47 2024 - [info] * Phase 4: Slaves Recovery Phase..
Sun Aug 25 10:33:47 2024 - [info] 
Sun Aug 25 10:33:47 2024 - [info] 
Sun Aug 25 10:33:47 2024 - [info] * Phase 4.1: Starting Slaves in parallel..
Sun Aug 25 10:33:47 2024 - [info] 
Sun Aug 25 10:33:47 2024 - [info] -- Slave recovery on host 172.25.254.30(172.25.254.30:3306) started, pid: 2545. Check tmp log /etc/masterha/172.25.254.30_3306_20240825103341.log if it takes time..
Sun Aug 25 10:33:49 2024 - [info] 
Sun Aug 25 10:33:49 2024 - [info] Log messages from 172.25.254.30 ...
Sun Aug 25 10:33:49 2024 - [info] 
Sun Aug 25 10:33:47 2024 - [info]  Resetting slave 172.25.254.30(172.25.254.30:3306) and starting replication from the new master 172.25.254.10(172.25.254.10:3306)..
Sun Aug 25 10:33:47 2024 - [info]  Executed CHANGE MASTER.
Sun Aug 25 10:33:48 2024 - [info]  Slave started.
Sun Aug 25 10:33:48 2024 - [info]  gtid_wait(7a6b31af-6228-11ef-bf1c-000c29fbe284:1,
b0a1e6d3-6227-11ef-b421-000c296d3bac:1-4) completed on 172.25.254.30(172.25.254.30:3306). Executed 0 events.
Sun Aug 25 10:33:49 2024 - [info] End of log messages from 172.25.254.30.
Sun Aug 25 10:33:49 2024 - [info] -- Slave on host 172.25.254.30(172.25.254.30:3306) started.
Sun Aug 25 10:33:49 2024 - [info] All new slave servers recovered successfully.
Sun Aug 25 10:33:49 2024 - [info] 
Sun Aug 25 10:33:49 2024 - [info] * Phase 5: New master cleanup phase..
Sun Aug 25 10:33:49 2024 - [info] 
Sun Aug 25 10:33:49 2024 - [info] Resetting slave info on the new master..
Sun Aug 25 10:33:49 2024 - [info]  172.25.254.10: Resetting slave info succeeded.
Sun Aug 25 10:33:49 2024 - [info] Master failover to 172.25.254.10(172.25.254.10:3306) completed successfully.
Sun Aug 25 10:33:49 2024 - [info] 

----- Failover Report -----

app1: MySQL Master failover 172.25.254.20(172.25.254.20:3306) to 172.25.254.10(172.25.254.10:3306) succeeded

Master 172.25.254.20(172.25.254.20:3306) is down!

Check MHA Manager logs at mysql-mha for details.

Started manual(interactive) failover.
Selected 172.25.254.10(172.25.254.10:3306) as a new master.
172.25.254.10(172.25.254.10:3306): OK: Applying all logs succeeded.
172.25.254.30(172.25.254.30:3306): OK: Slave started, replicating from 172.25.254.10(172.25.254.10:3306)
172.25.254.10(172.25.254.10:3306): Resetting slave info succeeded.
Master failover to 172.25.254.10(172.25.254.10:3306) completed successfully.

恢复故障mysql节点

bash 复制代码

[root@mysql-node2 ~]# /etc/init.d/mysqld start
Starting MySQL. SUCCESS! 
[root@mysql-node2 ~]# mysql -uroot -predhat
mysql> CHANGE MASTER TO MASTER_HOST='172.25.254.10', MASTER_USER='repl',MASTER_PASSWORD='redhat', MASTER_AUTO_POSITION=1;
Query OK, 0 rows affected, 2 warnings (0.01 sec)

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

测试一主两从是否正常

bash 复制代码

[root@mysql-mha ~]# masterha_check_repl --conf=/etc/masterha/app1.cnf
......
Sun Aug 25 10:40:14 2024 - [info] Checking replication health on 172.25.254.20..
Sun Aug 25 10:40:14 2024 - [info]  ok.
Sun Aug 25 10:40:14 2024 - [info] Checking replication health on 172.25.254.30..
Sun Aug 25 10:40:14 2024 - [info]  ok.
Sun Aug 25 10:40:14 2024 - [warning] master_ip_failover_script is not defined.
Sun Aug 25 10:40:14 2024 - [warning] shutdown_script is not defined.
Sun Aug 25 10:40:14 2024 - [info] Got exit code 0 (Not master dead).

MySQL Replication Health is OK.

自动切换

删掉切换锁文件

bash 复制代码

[root@mysql-mha ~]# rm -rf /etc/masterha/app1.failover.complete

启动mha监控程序

bash 复制代码

[root@mysql-mha ~]# masterha_manager --conf=/etc/masterha/app1.cnf
Sun Aug 25 11:05:05 2024 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sun Aug 25 11:05:05 2024 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Sun Aug 25 11:05:05 2024 - [info] Reading server configuration from /etc/masterha/app1.cnf..

监控程序通过指定配置文件监控master状态，当master出问题后自动切换并退出避免重复做故障切换

监测日志

bash 复制代码

[root@mysql-mha ~]# tail -f /etc/masterha/manager.log

模拟master故障

bash 复制代码

[root@mysql-node1 ~]# /etc/init.d/mysqld stop

监测日志记录切换的过程

bash 复制代码

[root@mysql-mha ~]# tail -f /etc/masterha/manager.log 
app1: MySQL Master failover 172.25.254.10(172.25.254.10:3306) to 172.25.254.20(172.25.254.20:3306) succeeded

Master 172.25.254.10(172.25.254.10:3306) is down!

Check MHA Manager logs at mysql-mha:/etc/masterha/manager.log for details.

Started automated(non-interactive) failover.
Selected 172.25.254.20(172.25.254.20:3306) as a new master.
172.25.254.20(172.25.254.20:3306): OK: Applying all logs succeeded.
172.25.254.30(172.25.254.30:3306): OK: Slave started, replicating from 172.25.254.20(172.25.254.20:3306)
172.25.254.20(172.25.254.20:3306): Resetting slave info succeeded.
Master failover to 172.25.254.20(172.25.254.20:3306) completed successfully.

恢复故障节点

bash 复制代码

[root@mysql-node1 ~]# /etc/init.d/mysqld start
Starting MySQL. SUCCESS! 
[root@mysql-node1 ~]# mysql -uroot -predhat
mysql> CHANGE MASTER TO MASTER_HOST='172.25.254.20', MASTER_USER='repl',MASTER_PASSWORD='redhat', MASTER_AUTO_POSITION=1;
Query OK, 0 rows affected, 2 warnings (0.00 sec)

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

清除锁文件

bash 复制代码

[root@mysql-mha ~]# rm -rf /etc/masterha/app1.failover.complete /etc/masterha/manager.log

测试一主两从是否正常

bash 复制代码

[root@mysql-mha ~]# masterha_check_repl --conf=/etc/masterha/app1.cnf
......
Sun Aug 25 11:21:54 2024 - [info] Checking replication health on 172.25.254.10..
Sun Aug 25 11:21:54 2024 - [info]  ok.
Sun Aug 25 11:21:54 2024 - [info] Checking replication health on 172.25.254.30..
Sun Aug 25 11:21:54 2024 - [info]  ok.
Sun Aug 25 11:21:54 2024 - [warning] master_ip_failover_script is not defined.
Sun Aug 25 11:21:54 2024 - [warning] shutdown_script is not defined.
Sun Aug 25 11:21:54 2024 - [info] Got exit code 0 (Not master dead).

MySQL Replication Health is OK.

6.2.3 为MHA添加VIP功能

编写迁移vip脚本

shell 复制代码

[root@mysql-mha ~]# vim /usr/local/bin/master_ip_failover
#!/usr/bin/env perl
use strict;
use warnings FATAL => 'all';
use Getopt::Long;

my (
    $command,          $ssh_user,        $orig_master_host, $orig_master_ip,
    $orig_master_port, $new_master_host, $new_master_ip,    $new_master_port
);

my $vip = '172.25.254.100/24';
my $ssh_start_vip = "/sbin/ip addr add $vip dev eth0";
my $ssh_stop_vip = "/sbin/ip addr del $vip dev eth0";

GetOptions(
    'command=s'          => \$command,
    'ssh_user=s'         => \$ssh_user,
    'orig_master_host=s' => \$orig_master_host,
    'orig_master_ip=s'   => \$orig_master_ip,
    'orig_master_port=i' => \$orig_master_port,
    'new_master_host=s'  => \$new_master_host,
    'new_master_ip=s'    => \$new_master_ip,
    'new_master_port=i'  => \$new_master_port,
);

exit &main();

sub main {

    print "\n\nIN SCRIPT TEST====$ssh_stop_vip==$ssh_start_vip===\n\n";

    if ( $command eq "stop" || $command eq "stopssh" ) {

        my $exit_code = 1;
        eval {
            print "Disabling the VIP on old master: $orig_master_host \n";
            &stop_vip();
            $exit_code = 0;
        };
        if ($@) {
            warn "Got Error: $@\n";
            exit $exit_code;
        }
        exit $exit_code;
    }
    elsif ( $command eq "start" ) {

        my $exit_code = 10;
        eval {
            print "Enabling the VIP - $vip on the new master - $new_master_host \n";
            &start_vip();
            $exit_code = 0;
        };
        if ($@) {
            warn $@;
            exit $exit_code;
        }
        exit $exit_code;
    }
    elsif ( $command eq "status" ) {
        print "Checking the Status of the script.. OK \n";
        exit 0;
    }
    else {
        &usage();
        exit 1;
    }
}

sub start_vip() {
    `ssh $ssh_user\@$new_master_host \" $ssh_start_vip \"`;
}
sub stop_vip() {
     return 0  unless  ($ssh_user);
    `ssh $ssh_user\@$orig_master_host \" $ssh_stop_vip \"`;
}

sub usage {
    print
    "Usage: master_ip_failover --command=start|stop|stopssh|status --orig_master_host=host --orig_master_ip=ip --orig_master_port=port --new_master_host=host --new_master_ip=ip --new_master_port=port\n";
}

在线切换时调用的vip迁移脚本

shell 复制代码

[root@mysql-mha ~]# vim /usr/local/bin/master_ip_online_change
#!/usr/bin/env perl
use strict;
use warnings FATAL =>'all';

use Getopt::Long;

my $vip = '172.25.254.100/24';
my $ssh_start_vip = "/sbin/ip addr add $vip dev eth0";
my $ssh_stop_vip = "/sbin/ip addr del $vip dev eth0";
my $exit_code = 0;

my (
  $command,              $orig_master_is_new_slave, $orig_master_host,
  $orig_master_ip,       $orig_master_port,         $orig_master_user,
  $orig_master_password, $orig_master_ssh_user,     $new_master_host,
  $new_master_ip,        $new_master_port,          $new_master_user,
  $new_master_password,  $new_master_ssh_user,
);
GetOptions(
  'command=s'                => \$command,
  'orig_master_is_new_slave' => \$orig_master_is_new_slave,
  'orig_master_host=s'       => \$orig_master_host,
  'orig_master_ip=s'         => \$orig_master_ip,
  'orig_master_port=i'       => \$orig_master_port,
  'orig_master_user=s'       => \$orig_master_user,
  'orig_master_password=s'   => \$orig_master_password,
  'orig_master_ssh_user=s'   => \$orig_master_ssh_user,
  'new_master_host=s'        => \$new_master_host,
  'new_master_ip=s'          => \$new_master_ip,
  'new_master_port=i'        => \$new_master_port,
  'new_master_user=s'        => \$new_master_user,
  'new_master_password=s'    => \$new_master_password,
  'new_master_ssh_user=s'    => \$new_master_ssh_user,
);


exit &main();

sub main {

#print "\n\nIN SCRIPT TEST====$ssh_stop_vip==$ssh_start_vip===\n\n";  

if ( $command eq "stop" || $command eq "stopssh" ) {

        # $orig_master_host, $orig_master_ip, $orig_master_port are passed.  
        # If you manage master ip address at global catalog database,  
        # invalidate orig_master_ip here.  
        my $exit_code = 1;
        eval {
            print "\n\n\n***************************************************************\n";
            print "Disabling the VIP - $vip on old master: $orig_master_host\n";
            print "***************************************************************\n\n\n\n";
&stop_vip();
            $exit_code = 0;
        };
        if ($@) {
            warn "Got Error: $@\n";
            exit $exit_code;
        }
        exit $exit_code;
}
elsif ( $command eq "start" ) {

        # all arguments are passed.  
        # If you manage master ip address at global catalog database,  
        # activate new_master_ip here.  
        # You can also grant write access (create user, set read_only=0, etc) here.  
my $exit_code = 10;
        eval {
            print "\n\n\n***************************************************************\n";
            print "Enabling the VIP - $vip on new master: $new_master_host \n";
            print "***************************************************************\n\n\n\n";
&start_vip();
            $exit_code = 0;
        };
        if ($@) {
            warn $@;
            exit $exit_code;
        }
        exit $exit_code;
}
elsif ( $command eq "status" ) {
        print "Checking the Status of the script.. OK \n";
        `ssh $orig_master_ssh_user\@$orig_master_host \" $ssh_start_vip \"`;
        exit 0;
}
else {
&usage();
        exit 1;
}
}

# A simple system call that enable the VIP on the new master  
sub start_vip() {
`ssh $new_master_ssh_user\@$new_master_host \" $ssh_start_vip \"`;
}
# A simple system call that disable the VIP on the old_master  
sub stop_vip() {
`ssh $orig_master_ssh_user\@$orig_master_host \" $ssh_stop_vip \"`;
}

sub usage {
print
"Usage: master_ip_failover --command=start|stop|stopssh|status --orig_master_host=host --orig_master_ip=ip --orig_master_port=port --new_master_host=host --new_master_ip=ip --new_master_port=port\n";
}

bash 复制代码

[root@mysql-mha ~]# chmod +x /usr/local/bin/master_ip_*

编辑配置文件

bash 复制代码

[root@mysql-mha ~]# vim /etc/masterha/app1.cnf
......
master_ip_failover_script= /usr/local/bin/master_ip_failover
master_ip_online_change_script= /usr/local/bin/master_ip_online_change
......

启动监控程序

bash 复制代码

[root@mysql-mha ~]# rm -rf /etc/masterha/app1.failover.complete 
[root@mysql-mha ~]# masterha_manager --conf=/etc/masterha/app1.cnf &

在master节点添加VIP

bash 复制代码

[root@mysql-node1 ~]# ip a a 172.25.254.100/24 dev eth0

模拟故障

关闭主节点服务

bash 复制代码

[root@mysql-node1 ~]# /etc/init.d/mysqld stop

监测日志

bash 复制代码

[root@mysql-mha ~]# tail -f /etc/masterha/manager.log
......
IN SCRIPT TEST====/sbin/ip addr del 172.25.254.100/24 dev eth0==/sbin/ip addr add 172.25.254.100/24 dev eth0===

Enabling the VIP - 172.25.254.100/24 on the new master - 172.25.254.20 
Sun Aug 25 12:08:46 2024 - [info]  OK.
......
Started automated(non-interactive) failover.
Invalidated master IP address on 172.25.254.10(172.25.254.10:3306)
Selected 172.25.254.20(172.25.254.20:3306) as a new master.
172.25.254.20(172.25.254.20:3306): OK: Applying all logs succeeded.
172.25.254.20(172.25.254.20:3306): OK: Activated master IP address.
172.25.254.30(172.25.254.30:3306): OK: Slave started, replicating from 172.25.254.20(172.25.254.20:3306)
172.25.254.20(172.25.254.20:3306): Resetting slave info succeeded.
Master failover to 172.25.254.20(172.25.254.20:3306) completed successfully.
......

查看VIP变化到node2上

bash 复制代码

[root@mysql-node2 ~]# ip a
......
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:fb:e2:84 brd ff:ff:ff:ff:ff:ff
    inet 172.25.254.20/24 brd 172.25.254.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet 172.25.254.11/24 scope global secondary eth0
       valid_lft forever preferred_lft forever
    inet 172.25.254.100/24 scope global secondary eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fefb:e284/64 scope link 
       valid_lft forever preferred_lft forever

恢复故障主机

bash 复制代码

[root@mysql-node1 ~]# /etc/init.d/mysqld start

mysql> CHANGE MASTER TO MASTER_HOST='172.25.254.20', MASTER_USER='repl', MASTER_PASSWORD='redhat', MASTER_AUTO_POSITION=1

[root@mysql-mha masterha]# rm -rf app1.failover.complete manager.log

手动切换后查看vip变化

bash 复制代码

[root@mysql-mha ~]# masterha_master_switch --conf=/etc/masterha/app1.cnf --master_state=alive --new_master_host=172.25.254.10 --new_master_port=3306 --orig_master_is_new_slave --running_updates_limit=10000
......
Sun Aug 25 12:19:23 2024 - [info]  172.25.254.10: Resetting slave info succeeded.
Sun Aug 25 12:19:23 2024 - [info] Switching master to 172.25.254.10(172.25.254.10:3306) completed successfully.

bash 复制代码

[root@mysql-node1 ~]# ip a
......
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:6d:3b:ac brd ff:ff:ff:ff:ff:ff
    inet 172.25.254.10/24 brd 172.25.254.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet 172.25.254.100/24 scope global secondary eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe6d:3bac/64 scope link 
       valid_lft forever preferred_lft forever