MHA高可用

MHA概述MHA的组成MHA特点使用场景：自动故障转移（Failover）和主从切换（Switchover）

shizhan_cloud

288人浏览 · 2026-05-12 19:51:02

shizhan_cloud · 2026-05-12 19:51:02 发布

MHA高可用

MHA介绍

MHA概述
- 一套优秀的MySQL高可用环境下故障切换和主从复制的软件
- MySQL故障过程中，MHA能做到0-30秒内自动完成故障切换
MHA的组成
- MHA Manager(管理节点)
- MHA Node(数据节点）
MHA特点
- 自动故障切换过程中，MHA试图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
- 目前MHA支持一主多从架构，最少三台服务，即一主两从

使用场景：自动故障转移（Failover）和主从切换（Switchover）

实验拓扑图

在这里插入图片描述

实验思路

1.MHA架构
1）数据库安装
2）一主两从
3）MHA搭建

2.故障模拟
1）主库失效
2）备选主库成为主库
3）从库2将备选主库指向为主库

案例环境

本案例环境

主机名	IP地址	作用
mysql-master	192.168.108.131	mysql主服务器，安装node组件
mysql-slave01	192.168.108.132	mysql从节点1，安装node组件
mysql-slave02	192.168.108.133	mysql从节点2，安装node组件
mha	192.168.108.130	amoeba，安装node组件、manager组件

这里操作系统是 CentOS7 版本，所以这里下载 MHA 版本是 0.57 版本。

案例需求
本案例要求通过 MHA 监控 MySQL 数据库在故障时进行自动切换，不影响业务。
案例实现思路
1）安装 MySQL 数据库
2）配置 MySQL 一主两从
3）安装 MHA 软件
4）配置无密码认证
5）配置 MySQL MHA 高可用
6）模拟 master 故障切换

在三台 MySQL 节点上分别安装前置环境

#主从是克隆的要做这个操作，否则UUID一致
[root@mysql-slave01 ~]# systemctl stop mysqld
[root@mysql-slave01 ~]# rm -f /usr/local/mysql/data/auto.cnf
[root@mysql-slave01 ~]# systemctl start mysqld

[root@mysql-slave02 ~]# systemctl stop mysqld
[root@mysql-slave02 ~]# rm -f /usr/local/mysql/data/auto.cnf
[root@mysql-slave02 ~]# systemctl start mysqld

安装编译依赖的环境

#mysql-master，mysql-slave01，mysql-slave02配置
[root@mysql-master ~]# yum -y install perl-Module-Install
[root@mysql-slave01 ~]# yum -y install perl-Module-Install
[root@mysql-slave02 ~]# yum -y install perl-Module-Install

修改 Master 的主配置文件/etc/my.cnf 文件

[root@mysql-master ~]# vim /etc/my.cnf
[mysqld]
server-id = 1                     #三台服务器的 server-id 不能一样
log_bin = master-bin
log-slave-updates = true

配置从服务器：
在/etc/my.cnf 中修改或者增加下面内容。

#mysql-slave01，请注释/etc/my.cnf 中 [client]下 #default-character-set=utf8
[root@mysql-slave01 ~]# vim /etc/my.cnf         #下面只列出了要改的内容
[client]
#default-character-set=utf8

[mysqld]
server-id = 2           
log_bin = master-bin                
relay-log = relay-log-bin 
relay-log-index = slave-relay-bin.index 

#mysql-slave02，请注释/etc/my.cnf 中 [client]下 #default-character-set=utf8
[root@mysql-slave02 ~]# vim /etc/my.cnf
[client]
#default-character-set=utf8

[mysqld]
server-id = 3                    
relay-log = relay-log-bin 
relay-log-index = slave-relay-bin.index

三节点都要操作

[root@mysql-master ~]# ln -s /usr/local/mysql/bin/mysqlbinlog /usr/bin/
[root@mysql-master ~]# ln -s /usr/local/mysql/bin/mysql /usr/bin/
[root@mysql-master ~]# systemctl restart mysqld

[root@mysql-slave01 ~]# ln -s /usr/local/mysql/bin/mysqlbinlog /usr/bin/
[root@mysql-slave01 ~]# ln -s /usr/local/mysql/bin/mysql /usr/bin/
[root@mysql-slave01 ~]# systemctl restart mysqld

[root@mysql-slave02 ~]# ln -s /usr/local/mysql/bin/mysqlbinlog /usr/bin/
[root@mysql-slave02 ~]# ln -s /usr/local/mysql/bin/mysql /usr/bin/
[root@mysql-slave02 ~]# systemctl restart mysqld

[!IMPORTANT]

mysql5.7注意

请注释/etc/my.cnf 中【client】下 #default-character-set=utf8

一定要注释，否则报错

ln -s /usr/local/mysql/bin/mysqlbinlog /usr/bin/
ln -s /usr/local/mysql/bin/mysql /usr/bin/

配置 MySQL 一主两从

MySQL 主从配置相对比较简单。需要注意的是授权。步骤如下：
在所有数据库节点上授权两个用户，一个是从库同步使用，另外一个是 manager 使用。

#mysql-master
mysql> grant replication slave on *.* to 'myslave'@'192.168.108.%' identified by '123';
mysql> grant all privileges on *.* to 'mha'@'192.168.108.%' identified by 'manager';
mysql> flush privileges;

#mysql-slave01
mysql> grant replication slave on *.* to 'myslave'@'192.168.108.%' identified by '123';
mysql> grant all privileges on *.* to 'mha'@'192.168.108.%' identified by 'manager';
mysql> flush privileges;

#mysql-slave02
mysql> grant replication slave on *.* to 'myslave'@'192.168.108.%' identified by '123';
mysql> grant all privileges on *.* to 'mha'@'192.168.108.%' identified by 'manager';
mysql> flush privileges;

下面三条授权按理论是不用添加的，但是做案例实验环境时候通过 MHA 检查MySQL 主从有报错，
报两个从库通过主机名连接不上主库，所以所有数据库加上下面的授权。

#mysql-master配置(mha@mysql-master与主机名相同)
mysql> grant all privileges on *.* to 'mha'@'mysql-master' identified by 'manager';       
mysql> grant all privileges on *.* to 'mha'@'mysql-slave01' identified by 'manager';
mysql> grant all privileges on *.* to 'mha'@'mysql-slave02' identified by 'manager';
mysql> flush privileges;

#mysql-slave01配置(mha@mysql-master与主机名相同)
mysql> grant all privileges on *.* to 'mha'@'mysql-master' identified by 'manager';       
mysql> grant all privileges on *.* to 'mha'@'mysql-slave01' identified by 'manager';
mysql> grant all privileges on *.* to 'mha'@'mysql-slave02' identified by 'manager';
mysql> flush privileges;

#mysql-slave02配置(mha@mysql-master与主机名相同)
mysql> grant all privileges on *.* to 'mha'@'mysql-master' identified by 'manager';       
mysql> grant all privileges on *.* to 'mha'@'mysql-slave01' identified by 'manager';
mysql> grant all privileges on *.* to 'mha'@'mysql-slave02' identified by 'manager';
mysql> flush privileges;

在mysql-master主机上查看二进制文件和同步点

mysql> show master status;
+-------------------+----------+--------------+------------------+-------------------+
| File              | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------------+----------+--------------+------------------+-------------------+
| master-bin.000001 |     1897 |              |                  |                   |
+-------------------+----------+--------------+------------------+-------------------+

接下来在 mysql-slave01 和 mysql-slave02分别执行同步。

#mysql-slave01，命令中的master_log_pos的值，取决于msql-master show master status查看的Position
mysql> change master to master_host='192.168.108.131',master_user='myslave',master_password='123',master_log_file='master-bin.000001',master_log_pos=1897; 
mysql> start slave;

#mysql-slave02
mysql> change master to master_host='192.168.108.131',master_user='myslave',master_password='123',master_log_file='master-bin.000001',master_log_pos=1897; 
mysql> start slave;

查看 IO 和 SQL 线程都是 yes 代表同步是否正常

#mysql-slave01
mysql> show slave status\G;
Slave_IO_Running: Yes
Slave_SQL_Running: Yes

#mysql-slave02
mysql> show slave status\G;
Slave_IO_Running: Yes
Slave_SQL_Running: Yes

必须设置两个从库为只读模式：

#mysql-slave01
mysql> set global read_only=1;

#mysql-slave02
mysql> set global read_only=1;

注意：设置完成直接验证主从复制功能

安装 MHA 软件

所有服务器上都安装 MHA 依赖的环境，首先安装 epel 源。

#4个节点
# yum install epel-release --nogpgcheck -y

# yum install -y perl-DBD-MySQL \
perl-Config-Tiny \
perl-Log-Dispatch \
perl-Parallel-ForkManager \
perl-ExtUtils-CBuilder \
perl-ExtUtils-MakeMaker \
perl-CPAN

MHA 软件包对于每个操作系统版本不一样，这里 CentOS7.9 必须选择 0.57 版本，

在<注意：所有服务器>上必须先安装 node 组件，最后在 MHA 节点上安装 manager 组件，
因为 manager 依赖 node 组件。

#mysql-master
[root@mysql-master ~]# tar zxvf mha4mysql-node-0.57.tar.gz
[root@mysql-master ~]# cd mha4mysql-node-0.57
[root@mysql-master ~]# perl Makefile.PL
[root@mysql-master ~]# make && make install

#mysql-slave01
[root@mysql-slave01 ~]# tar zxvf mha4mysql-node-0.57.tar.gz
[root@mysql-slave01 ~]# cd mha4mysql-node-0.57
[root@mysql-slave01 ~]# perl Makefile.PL
[root@mysql-slave01 ~]# make && make install

#mysql-slave02
[root@mysql-slave02 ~]# tar zxvf mha4mysql-node-0.57.tar.gz
[root@mysql-slave02 ~]# cd mha4mysql-node-0.57
[root@mysql-slave02 ~]# perl Makefile.PL
[root@mysql-slave02 ~]# make && make install

#mha
[root@mha ~]# tar zxvf mha4mysql-node-0.57.tar.gz
[root@mha ~]# cd mha4mysql-node-0.57
[root@mha ~]# perl Makefile.PL
[root@mha ~]# make && make install

在 MHA上安装 manager 组件（！注意：一定要先安装node 组件才能安装manager 组件）

#mha
[root@mha ~]# tar zxvf mha4mysql-manager-0.57.tar.gz
[root@mha ~]# cd mha4mysql-manager-0.57
[root@mha mha4mysql-manager-0.57]# perl Makefile.PL
[root@mha mha4mysql-manager-0.57]# make
[root@mha mha4mysql-manager-0.57]# make install

manager 安装后在/usr/local/bin 下面会生成几个工具，主要包括以下几个：
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 manager的脚本
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
masterha_stop 关闭manager

node 安装后也会在/usr/local/bin 下面会生成几个脚本（这些工具通常由 MHAManager 的脚本触发，无需人为操作）主要如下：

save_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）

配置无密码认证

在 manager 上配置到所有数据库节点的无密码认证

[root@mha ~]# ssh-keygen -t rsa             #一路按回车键
[root@mha ~]# ssh-copy-id 192.168.108.131
[root@mha ~]# ssh-copy-id 192.168.108.132
[root@mha ~]# ssh-copy-id 192.168.108.133

在 mysql-master 上配置到数据库节点mysql-slave01和mysql-slave02的无密码认证

[root@mysql-master ~]# ssh-keygen -t rsa
[root@mysql-master ~]# ssh-copy-id 192.168.108.132
[root@mysql-master ~]# ssh-copy-id 192.168.108.133

在 mysql-slave01 上配置到数据库节点mysql-master和mysql-slave02的无密码认证

[root@mysql-slave01 ~]# ssh-keygen -t rsa
[root@mysql-slave01 ~]# ssh-copy-id 192.168.108.131
[root@mysql-slave01 ~]# ssh-copy-id 192.168.108.133

在 mysql-slave02 上配置到数据库节点mysql-master和mysql-slave01的无密码认证

[root@mysql-slave02 ~]# ssh-keygen -t rsa
[root@mysql-slave02 ~]# ssh-copy-id 192.168.108.131
[root@mysql-slave02 ~]# ssh-copy-id 192.168.108.132

配置 MHA

在 manager 节点上复制相关脚本到/usr/local/bin 目录。

[root@mha ~]# cp -ra /root/mha4mysql-manager-0.57/samples/scripts /usr/local/bin

#拷贝后会有四个执行文件
[root@mha ~]# ll /usr/local/bin/scripts/
总用量 32
-rwxr-xr-x 1 mysql mysql 3648 5 月 31 2015 master_ip_failover  #自动切换时 VIP 管理的脚本
-rwxr-xr-x 1 mysql mysql 9872 5 月 25 09:07 master_ip_online_change #在线切换时 vip 的管理
-rwxr-xr-x 1 mysql mysql 11867 5 月 31 2015 power_manager #故障发生后关闭主机的脚本
-rwxr-xr-x 1 mysql mysql 1360 5 月 31 2015 send_report #因故障切换后发送报警的脚本

复制上述的自动切换时 VIP 管理的脚本到/usr/local/bin 目录，这里使用脚本管理 VIP，

[root@mha ~]# cp /usr/local/bin/scripts/master_ip_failover /usr/local/bin

修改内容如下：（删除原有内容，直接复制 :set paste复制）

[root@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
);
#############################添加内容部分#########################################
my $vip = '192.168.108.200';
my $brdc = '192.168.108.255';
my $ifdev = 'ens33';
my $key = '1';
my $ssh_start_vip = "/sbin/ifconfig ens33:$key $vip";
my $ssh_stop_vip = "/sbin/ifconfig ens33:$key down";
my $exit_code = 0;
#my $ssh_start_vip = "/usr/sbin/ip addr add $vip/24 brd $brdc dev $ifdev label $ifdev:$key;/usr/sbin/arping -q -A -c 1 -I $ifdev $vip;iptables -F;";
#my $ssh_stop_vip = "/usr/sbin/ip addr del $vip/24 dev $ifdev label $ifdev:$key";
##################################################################################
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 \"`;
}
# A simple system call that disable the VIP on the old_master
sub stop_vip() {
`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";
}

创建 MHA 软件目录并拷贝配置文件。

[root@mha ~]# mkdir /etc/masterha
[root@mha ~]# cp /root/mha4mysql-manager-0.57/samples/conf/app1.cnf /etc/masterha/
[root@mha ~]# vim /etc/masterha/app1.cnf
#全部删掉，替换
[server default]
manager_log=/var/log/masterha/app1/manager.log
manager_workdir=/var/log/masterha/app1
master_binlog_dir=/usr/local/mysql/data
#master_ip_failover_script=/usr/local/bin/master_ip_failover
master_ip_online_change_script=/usr/local/bin/master_ip_online_change
password=manager
ping_interval=1
remote_workdir=/tmp
repl_password=123
repl_user=myslave
secondary_check_script=/usr/local/bin/masterha_secondary_check -s 192.168.108.132 -s 192.168.108.133
shutdown_script=""
ssh_user=root
user=mha

[server1]
hostname=192.168.108.131
port=3306

[server2]
candidate_master=1
check_repl_delay=0
hostname=192.168.108.132
port=3306

[server3]
hostname=192.168.108.133
port=3306

配置文件解析

[server default]
manager_workdir=/var/log/masterha/app1.log　　　　　　　　　　　　　　 ##manager工作目录
manager_log=/var/log/masterha/app1/manager.log　　　　　　　　　　　　#manager日志
master_binlog_dir=/usr/local/mysql/data/　　　　　　　　　　　　　　　　#master保存binlog的位置，这里的路径要与master里配置的binlog的路径一致，以便mha能找到
#master_ip_failover_script= /usr/local/bin/master_ip_failover　　　　#设置自动failover时候的切换脚本，也就是上边的那个脚本
master_ip_online_change_script= /usr/local/bin/master_ip_online_change　　#设置手动切换时候的切换脚本
password=manager　　　　　　#设置mysql中mha用户的密码
user=mha　　　　　　　　#设置监控用户mha
ping_interval=1　　　　　　#设置监控主库，发送ping包的时间间隔，默认是3秒，尝试三次没有回应的时候自动进行railover
remote_workdir=/tmp　　　　#设置远端mysql在发生切换时binlog的保存位置
repl_password=123　　　　　　　　#设置复制用户的密码
repl_user=myslave　　　　　　 　　　　#设置复制用户的用户
report_script=/usr/local/send_report　　　　　　#设置发生切换后发送的报警的脚本
secondary_check_script=/usr/local/bin/masterha_secondary_check -s 192.168.108.132 -s 192.168.108.133
shutdown_script=""　　#设置故障发生后关闭故障主机脚本（该脚本的主要作用是关闭主机防止发生脑裂,这里没有使用）
ssh_user=root　　　　　　#设置ssh的登录用户名

[server1]
hostname=192.168.108.131
port=3306

[server2]
hostname=192.168.108.132
port=3306
candidate_master=1　　　　#//设置为候选master，如果设置该参数以后，发生主从切换以后将会将此从库提升为主库，即使这个主库不是集群中事件最新的slave
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

[server3]
hostname=192.168.108.133
port=3306

验证配置

测试 ssh 无密码认证，如果正常最后会输出 successfully，如下所示。

#检测SSH无密码认证
[root@mha ~]# masterha_check_ssh -conf=/etc/masterha/app1.cnf
Tue Oct  7 15:16:58 2025 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Tue Oct  7 15:16:58 2025 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Tue Oct  7 15:16:58 2025 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Tue Oct  7 15:16:58 2025 - [info] Starting SSH connection tests..
Tue Oct  7 15:16:58 2025 - [debug]
Tue Oct  7 15:16:58 2025 - [debug]  Connecting via SSH from root@192.168.108.131(192.168.108.131:22) to root@192.168.108.132(192.168.108.132:22)..
Tue Oct  7 15:16:58 2025 - [debug]   ok.
Tue Oct  7 15:16:58 2025 - [debug]  Connecting via SSH from root@192.168.108.131(192.168.108.131:22) to root@192.168.108.133(192.168.108.133:22)..
Tue Oct  7 15:16:58 2025 - [debug]   ok.
Tue Oct  7 15:16:59 2025 - [debug]
Tue Oct  7 15:16:58 2025 - [debug]  Connecting via SSH from root@192.168.108.132(192.168.108.132:22) to root@192.168.108.131(192.168.108.131:22)..
Tue Oct  7 15:16:58 2025 - [debug]   ok.
Tue Oct  7 15:16:58 2025 - [debug]  Connecting via SSH from root@192.168.108.132(192.168.108.132:22) to root@192.168.108.133(192.168.108.133:22)..
Tue Oct  7 15:16:59 2025 - [debug]   ok.
Tue Oct  7 15:16:59 2025 - [debug]
Tue Oct  7 15:16:59 2025 - [debug]  Connecting via SSH from root@192.168.108.133(192.168.108.133:22) to root@192.168.108.131(192.168.108.131:22)..
Tue Oct  7 15:16:59 2025 - [debug]   ok.
Tue Oct  7 15:16:59 2025 - [debug]  Connecting via SSH from root@192.168.108.133(192.168.108.133:22) to root@192.168.108.132(192.168.108.132:22)..
Tue Oct  7 15:16:59 2025 - [debug]   ok.
Tue Oct  7 15:16:59 2025 - [info] All SSH connection tests passed successfully.

#检测下主从复制
[root@mha ~]# masterha_check_repl -conf=/etc/masterha/app1.cnf
Tue Oct  7 15:30:03 2025 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Tue Oct  7 15:30:03 2025 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Tue Oct  7 15:30:03 2025 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Tue Oct  7 15:30:03 2025 - [info] MHA::MasterMonitor version 0.57.
Tue Oct  7 15:30:04 2025 - [info] GTID failover mode = 0
Tue Oct  7 15:30:04 2025 - [info] Dead Servers:
Tue Oct  7 15:30:04 2025 - [info] Alive Servers:
Tue Oct  7 15:30:04 2025 - [info]   192.168.108.131(192.168.108.131:3306)
Tue Oct  7 15:30:04 2025 - [info]   192.168.108.132(192.168.108.132:3306)
Tue Oct  7 15:30:04 2025 - [info]   192.168.108.133(192.168.108.133:3306)
Tue Oct  7 15:30:04 2025 - [info] Alive Slaves:
Tue Oct  7 15:30:04 2025 - [info]   192.168.108.132(192.168.108.132:3306)  Version=5.7.17-log (oldest major version between slaves) log-bin:enabled
Tue Oct  7 15:30:04 2025 - [info]     Replicating from 192.168.108.131(192.168.108.131:3306)
Tue Oct  7 15:30:04 2025 - [info]     Primary candidate for the new Master (candidate_master is set)
Tue Oct  7 15:30:04 2025 - [info]   192.168.108.133(192.168.108.133:3306)  Version=5.7.17 (oldest major version between slaves) log-bin:disabled
Tue Oct  7 15:30:04 2025 - [info]     Replicating from 192.168.108.131(192.168.108.131:3306)
Tue Oct  7 15:30:04 2025 - [info] Current Alive Master: 192.168.108.131(192.168.108.131:3306)
Tue Oct  7 15:30:04 2025 - [info] Checking slave configurations..
Tue Oct  7 15:30:04 2025 - [warning]  relay_log_purge=0 is not set on slave 192.168.108.132(192.168.108.132:3306).
Tue Oct  7 15:30:04 2025 - [warning]  relay_log_purge=0 is not set on slave 192.168.108.133(192.168.108.133:3306).
Tue Oct  7 15:30:04 2025 - [warning]  log-bin is not set on slave 192.168.108.133(192.168.108.133:3306). This host cannot be a master.
Tue Oct  7 15:30:04 2025 - [info] Checking replication filtering settings..
Tue Oct  7 15:30:04 2025 - [info]  binlog_do_db= , binlog_ignore_db=
Tue Oct  7 15:30:04 2025 - [info]  Replication filtering check ok.
Tue Oct  7 15:30:04 2025 - [info] GTID (with auto-pos) is not supported
Tue Oct  7 15:30:04 2025 - [info] Starting SSH connection tests..
Tue Oct  7 15:30:06 2025 - [info] All SSH connection tests passed successfully.
Tue Oct  7 15:30:06 2025 - [info] Checking MHA Node version..
Tue Oct  7 15:30:06 2025 - [info]  Version check ok.
Tue Oct  7 15:30:06 2025 - [info] Checking SSH publickey authentication settings on the current master..
Tue Oct  7 15:30:06 2025 - [info] HealthCheck: SSH to 192.168.108.131 is reachable.
Tue Oct  7 15:30:06 2025 - [info] Master MHA Node version is 0.57.
Tue Oct  7 15:30:06 2025 - [info] Checking recovery script configurations on 192.168.108.131(192.168.108.131:3306)..
Tue Oct  7 15:30:06 2025 - [info]   Executing command: save_binary_logs --command=test --start_pos=4 --binlog_dir=/usr/local/mysql/data --output_file=/tmp/save_binary_logs_test --manager_version=0.57 --start_file=master-bin.000002
Tue Oct  7 15:30:06 2025 - [info]   Connecting to root@192.168.108.131(192.168.108.131:22)..
  Creating /tmp if not exists..    ok.
  Checking output directory is accessible or not..
   ok.
  Binlog found at /usr/local/mysql/data, up to master-bin.000002
Tue Oct  7 15:30:06 2025 - [info] Binlog setting check done.
Tue Oct  7 15:30:06 2025 - [info] Checking SSH publickey authentication and checking recovery script configurations on all alive slave servers..
Tue Oct  7 15:30:06 2025 - [info]   Executing command : apply_diff_relay_logs --command=test --slave_user='mha' --slave_host=192.168.108.132 --slave_ip=192.168.108.132 --slave_port=3306 --workdir=/tmp --target_version=5.7.17-log --manager_version=0.57 --relay_log_info=/usr/local/mysql/data/relay-log.info  --relay_dir=/usr/local/mysql/data/  --slave_pass=xxx
Tue Oct  7 15:30:06 2025 - [info]   Connecting to root@192.168.108.132(192.168.108.132:22)..
  Checking slave recovery environment settings..
    Opening /usr/local/mysql/data/relay-log.info ... ok.
    Relay log found at /usr/local/mysql/data, up to relay-log-bin.000002
    Temporary relay log file is /usr/local/mysql/data/relay-log-bin.000002
    Testing mysql connection and privileges..mysql: [Warning] Using a password on the command line interface can be insecure.
 done.
    Testing mysqlbinlog output.. done.
    Cleaning up test file(s).. done.
Tue Oct  7 15:30:07 2025 - [info]   Executing command : apply_diff_relay_logs --command=test --slave_user='mha' --slave_host=192.168.108.133 --slave_ip=192.168.108.133 --slave_port=3306 --workdir=/tmp --target_version=5.7.17 --manager_version=0.57 --relay_log_info=/usr/local/mysql/data/relay-log.info  --relay_dir=/usr/local/mysql/data/  --slave_pass=xxx
Tue Oct  7 15:30:07 2025 - [info]   Connecting to root@192.168.108.133(192.168.108.133:22)..
  Checking slave recovery environment settings..
    Opening /usr/local/mysql/data/relay-log.info ... ok.
    Relay log found at /usr/local/mysql/data, up to relay-log-bin.000002
    Temporary relay log file is /usr/local/mysql/data/relay-log-bin.000002
    Testing mysql connection and privileges..mysql: [Warning] Using a password on the command line interface can be insecure.
 done.
    Testing mysqlbinlog output.. done.
    Cleaning up test file(s).. done.
Tue Oct  7 15:30:07 2025 - [info] Slaves settings check done.
Tue Oct  7 15:30:07 2025 - [info]
192.168.108.131(192.168.108.131:3306) (current master)
 +--192.168.108.132(192.168.108.132:3306)
 +--192.168.108.133(192.168.108.133:3306)

Tue Oct  7 15:30:07 2025 - [info] Checking replication health on 192.168.108.132..
Tue Oct  7 15:30:07 2025 - [info]  ok.
Tue Oct  7 15:30:07 2025 - [info] Checking replication health on 192.168.108.133..
Tue Oct  7 15:30:07 2025 - [info]  ok.
Tue Oct  7 15:30:07 2025 - [info] Checking master_ip_failover_script status:
Tue Oct  7 15:30:07 2025 - [info]   /usr/local/bin/master_ip_failover --command=status --ssh_user=root --orig_master_host=192.168.108.131 --orig_master_ip=192.168.108.131 --orig_master_port=3306


IN SCRIPT TEST====/sbin/ifconfig ens33:1 down==/sbin/ifconfig ens33:1 192.168.108.200===

Checking the Status of the script.. OK
Tue Oct  7 15:30:07 2025 - [info]  OK.
Tue Oct  7 15:30:07 2025 - [warning] shutdown_script is not defined.
Tue Oct  7 15:30:07 2025 - [info] Got exit code 0 (Not master dead).

MySQL Replicaxtion Health is OK.

第一次配置需要去master上手动开启虚拟IP

#注意：第一次配置需要去master上手动开启虚拟IP
[root@mysql-master ~]# /sbin/ifconfig ens33:1 192.168.108.200/24

启动 MHA

[root@mha ~]# nohup masterha_manager --conf=/etc/masterha/app1.cnf --remove_dead_master_conf --ignore_last_failover < /dev/null > /var/log/masterha/app1/manager.log 2>&1 &
[1] 48240

–remove_dead_master_conf 该参数代表当发生主从切换后，老的主库的 ip 将会从配置文件中移除。
–manger_log 日志存放位置。
–ignore_last_failover 在缺省情况下，如果 MHA 检测到连续发生宕机，且两次宕机间隔不足 8 小时的话，则不会进行 Failover，之所以这样限制是为了避免 ping-pong 效应。该参数代表忽略上次 MHA 触发切换产生的文件，默认情况下，MHA 发生切换后会在日志记目录，也就是上面设置的日志 app1.failover.complete 文件，下次再次切换的时候如果发现该目录下存在该文件将不允许触发切换，除非在第一次切换后收到删除该文件，为了方便，这里设置为-–ignore_last_failover。

查看 MHA 状态，可以看到当前的 master 是 mysql-master 节点。

[root@mha ~]# masterha_check_status --conf=/etc/masterha/app1.cnf
app1 (pid:48240) is running(0:PING_OK), master:192.168.108.131

查看 MHA 日志，也以看到当前的 master 是 192.168.108.131，如下所示。

[root@mha ~]# cat /var/log/masterha/app1/manager.log
......
Tue Oct  7 15:32:17 2025 - [info] Slaves settings check done.
Tue Oct  7 15:32:17 2025 - [info]
192.168.108.131(192.168.108.131:3306) (current master)
 +--192.168.108.132(192.168.108.132:3306)
 +--192.168.108.133(192.168.108.133:3306)

Tue Oct  7 15:32:17 2025 - [info] Checking master_ip_failover_script status:
Tue Oct  7 15:32:17 2025 - [info]   /usr/local/bin/master_ip_failover --command=status --ssh_user=root --orig_master_host=192.168.108.131 --orig_master_ip=192.168.108.131 --orig_master_port=3306


IN SCRIPT TEST====/sbin/ifconfig ens33:1 down==/sbin/ifconfig ens33:1 192.168.108.200===

Checking the Status of the script.. OK
Tue Oct  7 15:32:17 2025 - [info]  OK.
Tue Oct  7 15:32:17 2025 - [warning] shutdown_script is not defined.
Tue Oct  7 15:32:17 2025 - [info] Set master ping interval 1 seconds.
Tue Oct  7 15:32:17 2025 - [info] Set secondary check script: /usr/local/bin/masterha_secondary_check -s 192.168.108.132 -s 192.168.108.133
Tue Oct  7 15:32:17 2025 - [info] Starting ping health check on 192.168.108.131(192.168.108.131:3306)..
Tue Oct  7 15:32:17 2025 - [info] Ping(SELECT) succeeded, waiting until MySQL doesn't respond..
[root@mha ~]#

查看 mysql-master 的 VIP 地址 192.168.108.200 是否存在？,这个 VIP 地址不会因为
manager 节点停止 MHA 服务而消失。

[root@mysql-master ~]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.108.131  netmask 255.255.255.0  broadcast 192.168.108.255
        inet6 fe80::deb2:46ba:c54a:56ed  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:43:0b:39  txqueuelen 1000  (Ethernet)
        RX packets 42430  bytes 22790429 (21.7 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 29947  bytes 9476691 (9.0 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

ens33:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.108.200  netmask 255.255.255.0  broadcast 192.168.108.255
        ether 00:0c:29:43:0b:39  txqueuelen 1000  (Ethernet)

验证

#mha节点A窗口操作
[root@mha ~]# tailf /var/log/masterha/app1/manager.log     //启用监控观察日志记录

#mysql-master节点操作
[root@mysql-master ~]# pkill -9 mysql         //查看master变化，看上面命令的日志

#回到mha节点A窗口观察日志
[root@mha ~]# tailf /var/log/masterha/app1/manager.log

IN SCRIPT TEST====/sbin/ifconfig ens33:1 down==/sbin/ifconfig ens33:1 192.168.108.200===

Checking the Status of the script.. OK
Tue Oct  7 15:32:17 2025 - [info]  OK.
Tue Oct  7 15:32:17 2025 - [warning] shutdown_script is not defined.
Tue Oct  7 15:32:17 2025 - [info] Set master ping interval 1 seconds.
Tue Oct  7 15:32:17 2025 - [info] Set secondary check script: /usr/local/bin/masterha_secondary_check -s 192.168.108.132 -s 192.168.108.133
Tue Oct  7 15:32:17 2025 - [info] Starting ping health check on 192.168.108.131(192.168.108.131:3306)..
Tue Oct  7 15:32:17 2025 - [info] Ping(SELECT) succeeded, waiting until MySQL doesn't respond..
Tue Oct  7 15:39:47 2025 - [warning] Got error on MySQL select ping: 2006 (MySQL server has gone away)
Tue Oct  7 15:39:47 2025 - [info] Executing secondary network check script: /usr/local/bin/masterha_secondary_check -s 192.168.108.132 -s 192.168.108.133  --user=root  --master_host=192.168.108.131  --master_ip=192.168.108.131  --master_port=3306 --master_user=mha --master_password=manager --ping_type=SELECT
Tue Oct  7 15:39:47 2025 - [info] Executing SSH check script: save_binary_logs --command=test --start_pos=4 --binlog_dir=/usr/local/mysql/data --output_file=/tmp/save_binary_logs_test --manager_version=0.57 --binlog_prefix=master-bin
Tue Oct  7 15:39:47 2025 - [info] HealthCheck: SSH to 192.168.108.131 is reachable.
Master is reachable from 192.168.108.132!
Tue Oct  7 15:39:47 2025 - [warning] Master is reachable from at least one of other monitoring servers. Failover should not happen.
Tue Oct  7 15:39:48 2025 - [info] Ping(SELECT) succeeded, waiting until MySQL doesn't respond..

mha节点观察日志如下

pkill -9 mysql，mysqld短暂暂停又会启动

从其他节点依然能够访问master，不会主从切换

外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传

故障模拟

在主库上：

# master 停止mysql观察现象
[root@mysql-master ~]# systemctl stop mysqld   
# master切换成功

可以看到从库的状态，其中之一肯定有切换到主库的
切换备选主库的算法：
1.一般判断从库的是从（position/GTID）判断优劣，数据有差异，最接近于master的slave，成为备选主。
2.数据一致的情况下，按照配置文件顺序，选择备选主库。
3.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。

故障修复

1.修复db

[root@mysql-master ~]# systemctl start mysqld

修复主从

让slave01（备用master）成为master，让原master变成slave01

# mysql-slave01
mysql> show master status;
+-------------------+----------+--------------+------------------+-------------------+
| File              | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------------+----------+--------------+------------------+-------------------+
| master-bin.000002 |     2210 |              |                  |                   |
+-------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

# mysql-master操作
mysql> change master to master_host='192.168.108.132',master_user='myslave',master_password='123',master_log_file='master-bin.000002',master_log_pos=2210;       #这里的master_log_pos写mysq_slave01的
mysql> start slave;

继续查看

#mysql-master
mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.108.132         ---#主切换到了mysql-slave01
                  Master_User: myslave
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: master-bin.000002
          Read_Master_Log_Pos: 2210
               Relay_Log_File: mysql1-relay-bin.000002
                Relay_Log_Pos: 321
        Relay_Master_Log_File: master-bin.000002
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              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: 2210
              Relay_Log_Space: 529
              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: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error:
               Last_SQL_Errno: 0
               Last_SQL_Error:
  Replicate_Ignore_Server_Ids:
             Master_Server_Id: 2
                  Master_UUID: 865eeb1e-a383-11f0-8a5b-000c292673c8
             Master_Info_File: /usr/local/mysql/data/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:
     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

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