MySQL高可用之MHA

妍妍的宝贝2024-08-30 21:39

目录

[1 MySQL-HMA 介绍](#1 MySQL-HMA 介绍)

[1.1 为什么要用MHA？](#1.1 为什么要用MHA？)

[1.2 什么是 MHA？](#1.2 什么是 MHA？)

[1.3 MHA 的组成](#1.3 MHA 的组成)

[1.4 MHA 的特点](#1.4 MHA 的特点)

[1.5 故障切换备选主库的算法](#1.5 故障切换备选主库的算法)

[1.6 MHA工作原理](#1.6 MHA工作原理)

[2 MHA环境部署](#2 MHA环境部署)

[2.1 MHA环境安装](#2.1 MHA环境安装)

[2.2 搭建两从一主环境](#2.2 搭建两从一主环境)

[2.2.1 安装半同步插件并修改my.cnf文件](#2.2.1 安装半同步插件并修改my.cnf文件)

[2.2.2 实现MySQL的半同步模式](#2.2.2 实现MySQL的半同步模式)

[2.2.3 验证是否实现半同步模式](#2.2.3 验证是否实现半同步模式)

[3 MHA 配合半同步模式的使用](#3 MHA 配合半同步模式的使用)

[3.1 MHA 在软件中包含的工具包介绍](#3.1 MHA 在软件中包含的工具包介绍)

[3.2 配置MHA 的管理环境](#3.2 配置MHA 的管理环境)

[3.3 配置 MHA的主配置文件](#3.3 配置 MHA的主配置文件)

[3.4 使用工具进行环境检查](#3.4 使用工具进行环境检查)

[3.5 masterha_master_switch 参数说明](#3.5 masterha_master_switch 参数说明)

[3.5 环境说明](#3.5 环境说明)

[3.6 手动切换测试](#3.6 手动切换测试)

[3.6.1 故障模拟](#3.6.1 故障模拟)

[3.7 MHA之自动切换](#3.7 MHA之自动切换)

[3.7.1 将MASTER切换回MySQL-1](#3.7.1 将MASTER切换回MySQL-1)

[3.7.2 开启自动切换功能 masterha_manager](#3.7.2 开启自动切换功能 masterha_manager)

[3.7.3 模拟故障停掉MASTER](#3.7.3 模拟故障停掉MASTER)

[3.7.4 查看状态](#3.7.4 查看状态)

[3.8 MHA之 实现VIP功能](#3.8 MHA之 实现VIP功能)

[3.8.1 什么是MHA的VIP功能](#3.8.1 什么是MHA的VIP功能)

[3.8.2 使用 perl 脚本实现的VIP漂移](#3.8.2 使用 perl 脚本实现的VIP漂移)

[3.8.3 修改perl脚本关键参数](#3.8.3 修改perl脚本关键参数)

[3.8.4 赋予文件执行权限](#3.8.4 赋予文件执行权限)

[3.8.5 修改配置文件--指定脚本的路径](#3.8.5 修改配置文件--指定脚本的路径)

[3.8.6 测试自动切换VIP漂移](#3.8.6 测试自动切换VIP漂移)

[3.8.7 手动切换 实现 VIP 漂移](#3.8.7 手动切换 实现 VIP 漂移)

1 MySQL-HMA 介绍

1.1 为什么要用MHA？

Master的单点故障问题

1.2 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。

1.3 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。

1.4 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

1.5 故障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。

1.6 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。

本章节实验使用的环境

主从关系 节点 IP地址
MASTER MySQL-1 192.168.239.210
SLAVE-1 MySQL-2 192.168.239.220
SLAVE-2 MySQL-2 192.168.239.230
MHA MHA 192.168.239.50

2 MHA环境部署

2.1 MHA环境安装

MHA机子上：

bash 复制代码 
[root@docker-rhel ~]# ls
anaconda-ks.cfg  initial-setup-ks.cfg           MHA-7.zip                         vmset.sh  模板  图片  下载  桌面
centos7.tar      memc-nginx-module-0.20.tar.gz  srcache-nginx-module-0.33.tar.gz  公共      视频  文档  音乐

[root@docker-rhel ~]# unzip MHA-7.zip
[root@docker-rhel ~]# ls
anaconda-ks.cfg  initial-setup-ks.cfg           MHA-7      srcache-nginx-module-0.33.tar.gz  公共  视频  文档  音乐
centos7.tar      memc-nginx-module-0.20.tar.gz  MHA-7.zip  vmset.sh                          模板  图片  下载  桌面
[root@docker-rhel ~]# cd MHA-7/

[root@docker-rhel MHA-7]# ls
mha4mysql-manager-0.58-0.el7.centos.noarch.rpm  perl-Email-Date-Format-1.002-15.el7.noarch.rpm  perl-MIME-Lite-3.030-1.el7.noarch.rpm
mha4mysql-manager-0.58.tar.gz                   perl-Log-Dispatch-2.41-1.el7.1.noarch.rpm       perl-MIME-Types-1.38-2.el7.noarch.rpm
mha4mysql-node-0.58-0.el7.centos.noarch.rpm     perl-Mail-Sender-0.8.23-1.el7.noarch.rpm        perl-Net-Telnet-3.03-19.el7.noarch.rpm
perl-Config-Tiny-2.14-7.el7.noarch.rpm          perl-Mail-Sendmail-0.79-21.el7.noarch.rpm       perl-Parallel-ForkManager-1.18-2.el7.noarch.rpm

[root@docker-rhel MHA-7]#  yum install *.rpm -y


[root@docker-rhel MHA-7]# scp mha4mysql-node-0.58-0.el7.centos.noarch.rpm root@192.168.239.210:~    
[root@docker-rhel MHA-7]# scp mha4mysql-node-0.58-0.el7.centos.noarch.rpm root@192.168.239.220:~
[root@docker-rhel MHA-7]# scp mha4mysql-node-0.58-0.el7.centos.noarch.rpm root@192.168.239.230:~


# 三台数据库均需要安装
[root@mysql-01 ~]#  yum install /mnt/mha4mysql-node-0.58-0.el7.centos.noarch.rpm -y
[root@mysql-02 ~]#  yum install /mnt/mha4mysql-node-0.58-0.el7.centos.noarch.rpm -y
[root@mysql-03 ~]#  yum install /mnt/mha4mysql-node-0.58-0.el7.centos.noarch.rpm -y

2.2 搭建两从一主环境

2.2.1 安装半同步插件并修改my.cnf文件

bash 复制代码 
# MASTER
mysql> INSTALL PLUGIN rpl_semi_sync_master SONAME 'semisync_master.so';
mysql> INSTALL PLUGIN rpl_semi_sync_slave SONAME 'semisync_slave.so';

[root@mysql-01 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
server_id=10
log_bin=mysql-bin
gtid_mode=ON
enforce-gtid-consistency=ON
rpl_semi_sync_master_enabled = 1
rpl_semi_sync_slave_enabled = 1

[root@mysql-01 ~]# systemctl restart mysqld

# SLAVE-1

mysql> INSTALL PLUGIN rpl_semi_sync_master SONAME 'semisync_master.so';
mysql> INSTALL PLUGIN rpl_semi_sync_slave SONAME 'semisync_slave.so';

[root@mysql-02 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
symbolic-links=0
server_id=20
gtid_mode=ON
enforce-gtid-consistency=ON
rpl_semi_sync_slave_enabled=1
rpl_semi_sync_master_enabled=1
log_bin=mysql-bin

[root@mysql-02 ~]# systemctl restart mysqld

# SLAVE-2

mysql> INSTALL PLUGIN rpl_semi_sync_slave SONAME 'semisync_slave.so';

[root@mysql-03 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/data/mysql/mysql.sock
server-id=30
log-bin=mysql-bin
gtid_mode=ON
log_slave_updates=ON
enforce-gtid-consistency=ON
symbolic-links=0
rpl_semi_sync_slave_enabled=1
log_bin=mysql-bin

[root@mysql-03 ~]# systemctl restart mysqld

2.2.2 实现MySQL的半同步模式

sql 复制代码 
################################## MASTER ################################### 

CREATE USER 'repl'@'%' IDENTIFIED BY 'Openlab123!';
GRANT REPLICATION SLAVE ON *.* TO repl@'%';
FLUSH PRIVILEGES;


################################### SLAVE-1 ################################### 

CREATE USER 'repl'@'%' IDENTIFIED BY 'Openlab123!';
GRANT REPLICATION SLAVE ON *.* TO repl@'%';
FLUSH PRIVILEGES;
stop slave;
reset slave all;

change master to
master_host='192.168.239.210',
master_user='repl',
master_password='Openlab123!',
master_auto_position=1;

start slave;


#################################### SLAVE-2 ################################### 

CREATE USER 'repl'@'%' IDENTIFIED BY 'Openlab123!';
GRANT REPLICATION SLAVE ON *.* TO repl@'%';
FLUSH PRIVILEGES;
stop slave;
reset slave all;

change master to
master_host='192.168.239.210',
master_user='repl',
master_password='Openlab123!',
master_auto_position=1;

start slave;

2.2.3 验证是否实现半同步模式

sql 复制代码 
mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.239.210
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000016
          Read_Master_Log_Pos: 194
               Relay_Log_File: mysql-02-relay-bin.000002
                Relay_Log_Pos: 367
        Relay_Master_Log_File: mysql-bin.000016
             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: 194
              Relay_Log_Space: 577
              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: 10
                  Master_UUID: abe58cad-6282-11ef-a9ac-000c29a51779
             Master_Info_File: /data/mysql/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: abe58cad-6282-11ef-a9ac-000c29a51779:1-6,
d7f89afd-6282-11ef-ab48-000c299efdf0:1-5
                Auto_Position: 1
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.239.220
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000016
          Read_Master_Log_Pos: 194
               Relay_Log_File: mysql-03-relay-bin.000002
                Relay_Log_Pos: 367
        Relay_Master_Log_File: mysql-bin.000016
             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: 194
              Relay_Log_Space: 577
              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: 20
                  Master_UUID: d7f89afd-6282-11ef-ab48-000c299efdf0
             Master_Info_File: /data/mysql/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: abe58cad-6282-11ef-a9ac-000c29a51779:1-6,
abe65851-6282-11ef-bf19-000c298f2a8a:1,
d7f89afd-6282-11ef-ab48-000c299efdf0:1-5
                Auto_Position: 1
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)

查看 master 与 slave 1 是否加载了半同步插件

sql 复制代码 
#############################  MASTER   ################################### 
mysql> show status like 'Rpl%';
+--------------------------------------------+-------+
| Variable_name                              | Value |
+--------------------------------------------+-------+
| Rpl_semi_sync_master_clients               | 2     |
| 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     |
| Rpl_semi_sync_slave_status                 | OFF   |
+--------------------------------------------+-------+

 #############################  SLAVE-1   ################################### 

mysql> show status like 'Rpl_semi_sync%';
+--------------------------------------------+-------+
| Variable_name                              | Value |
+--------------------------------------------+-------+
| Rpl_semi_sync_master_clients               | 2     |
| 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     |
| Rpl_semi_sync_slave_status                 | ON    |
+--------------------------------------------+-------+

MySQL-1

MySQL-2

3 MHA 配合半同步模式的使用

3.1 MHA 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：

工具名称 功能描述
masterha_check_ssh 检查 MHA 的 SSH 配置状况
masterha_check_repl 检查 MySQL 复制状况
masterha_manager 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）

工具名称 功能描述
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到其他 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）

3.2 配置MHA的管理环境

bash 复制代码 
[root@docker-rhel masterha]# 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.

3.3 配置 MHA的主配置文件

-- 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

bash 复制代码 
[root@docker-rhel ~]# mkdir /etc/masterha
[root@docker-rhel MHA-7]# tar zxf mha4mysql-manager-0.58.tar.gz
[root@docker-rhel MHA-7]# cd mha4mysql-manager-0.58/samples/conf/
[root@docker-rhel conf]# cat masterha_default.cnf app1.cnf > /etc/masterha/app1.cnf
bash 复制代码 
[root@docker-rhel masterha]# vim /etc/masterha/app1.cnf
[server default]
#mysql管理员用户，因为需要做自动化配置
user=root
# MySQL 用户名
password=Openlab123!
# MySQL 密码
ssh_user=root
# SSH 用户名
master_binlog_dir=/data/mysql # 主服务器的二进制日志目录
remote_workdir=/tmp  # 远程工作目录

repl_user=repl  #mysql主从复制中负责认证的用户
repl_password=Openlab123!  #mysql主从复制中负责认证的用户密码
secondary_check_script=masterha_secondary_check -s 192.168.239.210 -s 192.168.239.211
# 检查从服务器状态的脚本   其中 192.168.239.210 为MASTER 的IP地址  
# 192.168.239.211 为备用地址 假如说找不到192.168.239.210 就找192.168.239.211

ping_interval=3
# 心跳间隔（秒）
# master_ip_failover_script=/usr/local/bin/master_ip_failover
# 主服务器故障切换脚本
# shutdown_script=/script/masterha/power_manager
# 关闭脚本
# report_script=/script/masterha/send_report
# 报告脚本
# master_ip_online_change_script=/usr/local/bin/master_ip_online_change
# 主服务器在线更改脚本

[server default]
# 默认服务器配置
manager_workdir=/etc/masterha
# 管理器工作目录
manager_log=/etc/masterha/manager.log
# 管理器日志文件

[server1]
# 服务器1配置
hostname=192.168.239.210
# 主机名
candidate_master=1
                        ##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]
# 服务器2配置
hostname=192.168.239.220
# 主机名
candidate_master=1
# 是否候选主服务器
check_repl_delay=0
# 检查复制延迟（秒）

[server3]
# 服务器3配置
hostname=192.168.239.230
# 主机名
no_master=1
# 不为主服务器

增加master IP地址

bash 复制代码 
[root@mysql-01 ~]# ip addr add 192.168.239.211/24 dev eth0

注意：

三台主机必须做相互的免密登录不然无法使用mha

3.4 使用工具进行环境检查

检查环境是否适合

bash 复制代码 
[root@docker-rhel ~]# masterha_check_ssh --conf=/etc/masterha/app1.cnf
bash 复制代码 
[root@docker-rhel ~]# masterha_check_repl --conf=/etc/masterha/app1.cnf

3.5 masterha_master_switch 参数说明

参数 描述
--conf 指定 MHA 配置文件的位置，例如：/etc/masterha/app1.cnf
--master_state 指定主服务器的状态，这里为 alive 表示主服务器处于活动状态
--new_master_host 新的主服务器的 IP 地址，例如：192.168.239.220
--new_master_port 新的主服务器的端口，例如：3306
--orig_master_is_new_slave 标记原始主服务器成为新的从服务器
--running_updates_limit 在切换过程中允许的最大更新数量，例如：10000

3.5 环境说明

--- 以上已经搭过环境了

主从关系 节点 IP地址
MASTER MySQL-1 192.168.239.210
SLAVE-1 MySQL-2 192.168.239.220
SLAVE-2 MySQL-2 192.168.239.230
MHA MHA 192.168.239.50

3.6 手动切换测试

bash 复制代码 
[root@docker-rhel masterha]# masterha_master_switch \
--conf=/etc/masterha/app1.cnf \
--master_state=alive \
--new_master_host=192.168.239.220 \
--new_master_port=3306 \
--orig_master_is_new_slave \
--running_updates_limit=10000

Sun Aug 25 22:39:09 2024 - [info] MHA::MasterRotate version 0.58.
Sun Aug 25 22:39:09 2024 - [info] Starting online master switch..
Sun Aug 25 22:39:09 2024 - [info] 
Sun Aug 25 22:39:09 2024 - [info] * Phase 1: Configuration Check Phase..
Sun Aug 25 22:39:09 2024 - [info] 
Sun Aug 25 22:39:09 2024 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sun Aug 25 22:39:09 2024 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Sun Aug 25 22:39:09 2024 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Sun Aug 25 22:39:10 2024 - [info] GTID failover mode = 1
Sun Aug 25 22:39:10 2024 - [info] Current Alive Master: 192.168.239.210(192.168.239.210:3306)
Sun Aug 25 22:39:10 2024 - [info] Alive Slaves:
Sun Aug 25 22:39:10 2024 - [info]   192.168.239.220(192.168.239.220:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 22:39:10 2024 - [info]     GTID ON
Sun Aug 25 22:39:10 2024 - [info]     Replicating from 192.168.239.210(192.168.239.210:3306)
Sun Aug 25 22:39:10 2024 - [info]     Primary candidate for the new Master (candidate_master is set)
Sun Aug 25 22:39:10 2024 - [info]   192.168.239.230(192.168.239.230:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 22:39:10 2024 - [info]     GTID ON
Sun Aug 25 22:39:10 2024 - [info]     Replicating from 192.168.239.210(192.168.239.210:3306)
Sun Aug 25 22:39:10 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 192.168.239.210(192.168.239.210:3306)? (YES/no): yes
Sun Aug 25 22:39:11 2024 - [info] Executing FLUSH NO_WRITE_TO_BINLOG TABLES. This may take long time..
Sun Aug 25 22:39:11 2024 - [info]  ok.
Sun Aug 25 22:39:11 2024 - [info] Checking MHA is not monitoring or doing failover..
Sun Aug 25 22:39:11 2024 - [info] Checking replication health on 192.168.239.220..
Sun Aug 25 22:39:11 2024 - [info]  ok.
Sun Aug 25 22:39:11 2024 - [info] Checking replication health on 192.168.239.230..
Sun Aug 25 22:39:11 2024 - [info]  ok.
Sun Aug 25 22:39:11 2024 - [info] 192.168.239.220 can be new master.
Sun Aug 25 22:39:11 2024 - [info] 
From:
192.168.239.210(192.168.239.210:3306) (current master)
 +--192.168.239.220(192.168.239.220:3306)
 +--192.168.239.230(192.168.239.230:3306)

To:
192.168.239.220(192.168.239.220:3306) (new master)
 +--192.168.239.230(192.168.239.230:3306)
 +--192.168.239.210(192.168.239.210:3306)

Starting master switch from 192.168.239.210(192.168.239.210:3306) to 192.168.239.220(192.168.239.220:3306)? (yes/NO): yes
Sun Aug 25 22:39:13 2024 - [info] Checking whether 192.168.239.220(192.168.239.220:3306) is ok for the new master..
Sun Aug 25 22:39:13 2024 - [info]  ok.
Sun Aug 25 22:39:13 2024 - [info] 192.168.239.210(192.168.239.210:3306): SHOW SLAVE STATUS returned empty result. To check replication filtering rules, temporarily executing CHANGE MASTER to a dummy host.
Sun Aug 25 22:39:13 2024 - [info] 192.168.239.210(192.168.239.210:3306): Resetting slave pointing to the dummy host.
Sun Aug 25 22:39:13 2024 - [info] ** Phase 1: Configuration Check Phase completed.
Sun Aug 25 22:39:13 2024 - [info] 
Sun Aug 25 22:39:13 2024 - [info] * Phase 2: Rejecting updates Phase..
Sun Aug 25 22:39:13 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 22:39:14 2024 - [info] Locking all tables on the orig master to reject updates from everybody (including root):
Sun Aug 25 22:39:14 2024 - [info] Executing FLUSH TABLES WITH READ LOCK..
Sun Aug 25 22:39:14 2024 - [info]  ok.
Sun Aug 25 22:39:14 2024 - [info] Orig master binlog:pos is mysql-bin.000016:194.
Sun Aug 25 22:39:14 2024 - [info]  Waiting to execute all relay logs on 192.168.239.220(192.168.239.220:3306)..
Sun Aug 25 22:39:14 2024 - [info]  master_pos_wait(mysql-bin.000016:194) completed on 192.168.239.220(192.168.239.220:3306). Executed 0 events.
Sun Aug 25 22:39:14 2024 - [info]   done.
Sun Aug 25 22:39:14 2024 - [info] Getting new master's binlog name and position..
Sun Aug 25 22:39:14 2024 - [info]  mysql-bin.000017:194
Sun Aug 25 22:39:14 2024 - [info]  All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST='192.168.239.220', MASTER_PORT=3306, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='xxx';
Sun Aug 25 22:39:14 2024 - [info] Setting read_only=0 on 192.168.239.220(192.168.239.220:3306)..
Sun Aug 25 22:39:14 2024 - [info]  ok.
Sun Aug 25 22:39:14 2024 - [info] 
Sun Aug 25 22:39:14 2024 - [info] * Switching slaves in parallel..
Sun Aug 25 22:39:14 2024 - [info] 
Sun Aug 25 22:39:14 2024 - [info] -- Slave switch on host 192.168.239.230(192.168.239.230:3306) started, pid: 13067
Sun Aug 25 22:39:14 2024 - [info] 
Sun Aug 25 22:39:16 2024 - [info] Log messages from 192.168.239.230 ...
Sun Aug 25 22:39:16 2024 - [info] 
Sun Aug 25 22:39:14 2024 - [info]  Waiting to execute all relay logs on 192.168.239.230(192.168.239.230:3306)..
Sun Aug 25 22:39:14 2024 - [info]  master_pos_wait(mysql-bin.000016:194) completed on 192.168.239.230(192.168.239.230:3306). Executed 0 events.
Sun Aug 25 22:39:14 2024 - [info]   done.
Sun Aug 25 22:39:14 2024 - [info]  Resetting slave 192.168.239.230(192.168.239.230:3306) and starting replication from the new master 192.168.239.220(192.168.239.220:3306)..
Sun Aug 25 22:39:14 2024 - [info]  Executed CHANGE MASTER.
Sun Aug 25 22:39:15 2024 - [info]  Slave started.
Sun Aug 25 22:39:16 2024 - [info] End of log messages from 192.168.239.230 ...
Sun Aug 25 22:39:16 2024 - [info] 
Sun Aug 25 22:39:16 2024 - [info] -- Slave switch on host 192.168.239.230(192.168.239.230:3306) succeeded.
Sun Aug 25 22:39:16 2024 - [info] Unlocking all tables on the orig master:
Sun Aug 25 22:39:16 2024 - [info] Executing UNLOCK TABLES..
Sun Aug 25 22:39:16 2024 - [info]  ok.
Sun Aug 25 22:39:16 2024 - [info] Starting orig master as a new slave..
Sun Aug 25 22:39:16 2024 - [info]  Resetting slave 192.168.239.210(192.168.239.210:3306) and starting replication from the new master 192.168.239.220(192.168.239.220:3306)..
Sun Aug 25 22:39:16 2024 - [info]  Executed CHANGE MASTER.
Sun Aug 25 22:39:17 2024 - [info]  Slave started.
Sun Aug 25 22:39:17 2024 - [info] All new slave servers switched successfully.
Sun Aug 25 22:39:17 2024 - [info] 
Sun Aug 25 22:39:17 2024 - [info] * Phase 5: New master cleanup phase..
Sun Aug 25 22:39:17 2024 - [info] 
Sun Aug 25 22:39:17 2024 - [info]  192.168.239.220: Resetting slave info succeeded.
Sun Aug 25 22:39:17 2024 - [info] Switching master to 192.168.239.220(192.168.239.220:3306) completed successfully.

3.6.1 故障模拟

实际环境中会出现down机的情况

模拟down机情况做出方法模拟

bash 复制代码 
[root@mysql-01 ~]# service mysqld stop 
Shutting down MySQL. SUCCESS!
参数 描述
--master_state 主服务器的状态，这里为 dead 表示主服务器已死机
--conf 指定 MHA 配置文件的位置，例如：/etc/masterha/app1.cnf
--dead_master_host 死机的主服务器的 IP 地址，例如：192.168.239.210
--dead_master_port 死机的主服务器的端口，例如：3306
--new_master_host 新的主服务器的 IP 地址，例如：192.168.239.220
--new_master_port 新的主服务器的端口，例如：3306
--ignore_last_failover 忽略最近一次的故障转移记录（忽略锁表）
bash 复制代码 
[root@docker-rhel masterha]# masterha_master_switch \
--master_state=dead \
--conf=/etc/masterha/app1.cnf \
--dead_master_host=192.168.239.210 \
--dead_master_port=3306 \
--new_master_host=192.168.239.220 \
--new_master_port=3306 \
--ignore_last_failover


--dead_master_ip=<dead_master_ip> is not set. Using 192.168.239.210.
Sun Aug 25 23:07:55 2024 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sun Aug 25 23:07:55 2024 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Sun Aug 25 23:07:55 2024 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Sun Aug 25 23:07:55 2024 - [info] MHA::MasterFailover version 0.58.
Sun Aug 25 23:07:55 2024 - [info] Starting master failover.
Sun Aug 25 23:07:55 2024 - [info] 
Sun Aug 25 23:07:55 2024 - [info] * Phase 1: Configuration Check Phase..
Sun Aug 25 23:07:55 2024 - [info] 
Sun Aug 25 23:07:56 2024 - [info] GTID failover mode = 1
Sun Aug 25 23:07:56 2024 - [info] Dead Servers:
Sun Aug 25 23:07:56 2024 - [info]   192.168.239.210(192.168.239.210:3306)
Sun Aug 25 23:07:56 2024 - [info] Checking master reachability via MySQL(double check)...
Sun Aug 25 23:07:56 2024 - [info]  ok.
Sun Aug 25 23:07:56 2024 - [info] Alive Servers:
Sun Aug 25 23:07:56 2024 - [info]   192.168.239.220(192.168.239.220:3306)
Sun Aug 25 23:07:56 2024 - [info]   192.168.239.230(192.168.239.230:3306)
Sun Aug 25 23:07:56 2024 - [info] Alive Slaves:
Sun Aug 25 23:07:56 2024 - [info]   192.168.239.220(192.168.239.220:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 23:07:56 2024 - [info]     GTID ON
Sun Aug 25 23:07:56 2024 - [info]     Replicating from 192.168.239.210(192.168.239.210:3306)
Sun Aug 25 23:07:56 2024 - [info]     Primary candidate for the new Master (candidate_master is set)
Sun Aug 25 23:07:56 2024 - [info]   192.168.239.230(192.168.239.230:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 23:07:56 2024 - [info]     GTID ON
Sun Aug 25 23:07:56 2024 - [info]     Replicating from 192.168.239.210(192.168.239.210:3306)
Sun Aug 25 23:07:56 2024 - [info]     Not candidate for the new Master (no_master is set)
Master 192.168.239.210(192.168.239.210:3306) is dead. Proceed? (yes/NO): yes
Sun Aug 25 23:07:57 2024 - [info] Starting GTID based failover.
Sun Aug 25 23:07:57 2024 - [info] 
Sun Aug 25 23:07:57 2024 - [info] ** Phase 1: Configuration Check Phase completed.
Sun Aug 25 23:07:57 2024 - [info] 
Sun Aug 25 23:07:57 2024 - [info] * Phase 2: Dead Master Shutdown Phase..
Sun Aug 25 23:07:57 2024 - [info] 
Sun Aug 25 23:07:58 2024 - [info] HealthCheck: SSH to 192.168.239.210 is reachable.
Sun Aug 25 23:07:58 2024 - [info] Forcing shutdown so that applications never connect to the current master..
Sun Aug 25 23:07:58 2024 - [warning] master_ip_failover_script is not set. Skipping invalidating dead master IP address.
Sun Aug 25 23:07:58 2024 - [warning] shutdown_script is not set. Skipping explicit shutting down of the dead master.
Sun Aug 25 23:07:58 2024 - [info] * Phase 2: Dead Master Shutdown Phase completed.
Sun Aug 25 23:07:58 2024 - [info] 
Sun Aug 25 23:07:58 2024 - [info] * Phase 3: Master Recovery Phase..
Sun Aug 25 23:07:58 2024 - [info] 
Sun Aug 25 23:07:58 2024 - [info] * Phase 3.1: Getting Latest Slaves Phase..
Sun Aug 25 23:07:58 2024 - [info] 
Sun Aug 25 23:07:58 2024 - [info] The latest binary log file/position on all slaves is mysql-bin.000017:194
Sun Aug 25 23:07:58 2024 - [info] Latest slaves (Slaves that received relay log files to the latest):
Sun Aug 25 23:07:58 2024 - [info]   192.168.239.220(192.168.239.220:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 23:07:58 2024 - [info]     GTID ON
Sun Aug 25 23:07:58 2024 - [info]     Replicating from 192.168.239.210(192.168.239.210:3306)
Sun Aug 25 23:07:58 2024 - [info]     Primary candidate for the new Master (candidate_master is set)
Sun Aug 25 23:07:58 2024 - [info]   192.168.239.230(192.168.239.230:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 23:07:58 2024 - [info]     GTID ON
Sun Aug 25 23:07:58 2024 - [info]     Replicating from 192.168.239.210(192.168.239.210:3306)
Sun Aug 25 23:07:58 2024 - [info]     Not candidate for the new Master (no_master is set)
Sun Aug 25 23:07:58 2024 - [info] The oldest binary log file/position on all slaves is mysql-bin.000017:194
Sun Aug 25 23:07:58 2024 - [info] Oldest slaves:
Sun Aug 25 23:07:58 2024 - [info]   192.168.239.220(192.168.239.220:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 23:07:58 2024 - [info]     GTID ON
Sun Aug 25 23:07:58 2024 - [info]     Replicating from 192.168.239.210(192.168.239.210:3306)
Sun Aug 25 23:07:58 2024 - [info]     Primary candidate for the new Master (candidate_master is set)
Sun Aug 25 23:07:58 2024 - [info]   192.168.239.230(192.168.239.230:3306)  Version=5.7.44-log (oldest major version between slaves) log-bin:enabled
Sun Aug 25 23:07:58 2024 - [info]     GTID ON
Sun Aug 25 23:07:58 2024 - [info]     Replicating from 192.168.239.210(192.168.239.210:3306)
Sun Aug 25 23:07:58 2024 - [info]     Not candidate for the new Master (no_master is set)
Sun Aug 25 23:07:58 2024 - [info] 
Sun Aug 25 23:07:58 2024 - [info] * Phase 3.3: Determining New Master Phase..
Sun Aug 25 23:07:58 2024 - [info] 
Sun Aug 25 23:07:58 2024 - [info] 192.168.239.220 can be new master.
Sun Aug 25 23:07:58 2024 - [info] New master is 192.168.239.220(192.168.239.220:3306)
Sun Aug 25 23:07:58 2024 - [info] Starting master failover..
Sun Aug 25 23:07:58 2024 - [info] 
From:
192.168.239.210(192.168.239.210:3306) (current master)
 +--192.168.239.220(192.168.239.220:3306)
 +--192.168.239.230(192.168.239.230:3306)

To:
192.168.239.220(192.168.239.220:3306) (new master)
 +--192.168.239.230(192.168.239.230:3306)

Starting master switch from 192.168.239.210(192.168.239.210:3306) to 192.168.239.220(192.168.239.220:3306)? (yes/NO): yes
Sun Aug 25 23:07:59 2024 - [info] New master decided manually is 192.168.239.220(192.168.239.220:3306)
Sun Aug 25 23:07:59 2024 - [info] 
Sun Aug 25 23:07:59 2024 - [info] * Phase 3.3: New Master Recovery Phase..
Sun Aug 25 23:07:59 2024 - [info] 
Sun Aug 25 23:07:59 2024 - [info]  Waiting all logs to be applied.. 
Sun Aug 25 23:07:59 2024 - [info]   done.
Sun Aug 25 23:07:59 2024 - [info] Getting new master's binlog name and position..
Sun Aug 25 23:07:59 2024 - [info]  mysql-bin.000017:194
Sun Aug 25 23:07:59 2024 - [info]  All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST='192.168.239.220', MASTER_PORT=3306, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='xxx';
Sun Aug 25 23:07:59 2024 - [info] Master Recovery succeeded. File:Pos:Exec_Gtid_Set: mysql-bin.000017, 194, abe58cad-6282-11ef-a9ac-000c29a51779:1-6,
d7f89afd-6282-11ef-ab48-000c299efdf0:1-5
Sun Aug 25 23:07:59 2024 - [warning] master_ip_failover_script is not set. Skipping taking over new master IP address.
Sun Aug 25 23:07:59 2024 - [info] Setting read_only=0 on 192.168.239.220(192.168.239.220:3306)..
Sun Aug 25 23:07:59 2024 - [info]  ok.
Sun Aug 25 23:07:59 2024 - [info] ** Finished master recovery successfully.
Sun Aug 25 23:07:59 2024 - [info] * Phase 3: Master Recovery Phase completed.
Sun Aug 25 23:07:59 2024 - [info] 
Sun Aug 25 23:07:59 2024 - [info] * Phase 4: Slaves Recovery Phase..
Sun Aug 25 23:07:59 2024 - [info] 
Sun Aug 25 23:07:59 2024 - [info] 
Sun Aug 25 23:07:59 2024 - [info] * Phase 4.1: Starting Slaves in parallel..
Sun Aug 25 23:07:59 2024 - [info] 
Sun Aug 25 23:07:59 2024 - [info] -- Slave recovery on host 192.168.239.230(192.168.239.230:3306) started, pid: 13538. Check tmp log /etc/masterha/192.168.239.230_3306_20240825230755.log if it takes time..
Sun Aug 25 23:08:01 2024 - [info] 
Sun Aug 25 23:08:01 2024 - [info] Log messages from 192.168.239.230 ...
Sun Aug 25 23:08:01 2024 - [info] 
Sun Aug 25 23:07:59 2024 - [info]  Resetting slave 192.168.239.230(192.168.239.230:3306) and starting replication from the new master 192.168.239.220(192.168.239.220:3306)..
Sun Aug 25 23:07:59 2024 - [info]  Executed CHANGE MASTER.
Sun Aug 25 23:08:00 2024 - [info]  Slave started.
Sun Aug 25 23:08:00 2024 - [info]  gtid_wait(abe58cad-6282-11ef-a9ac-000c29a51779:1-6,
d7f89afd-6282-11ef-ab48-000c299efdf0:1-5) completed on 192.168.239.230(192.168.239.230:3306). Executed 0 events.
Sun Aug 25 23:08:01 2024 - [info] End of log messages from 192.168.239.230.
Sun Aug 25 23:08:01 2024 - [info] -- Slave on host 192.168.239.230(192.168.239.230:3306) started.
Sun Aug 25 23:08:01 2024 - [info] All new slave servers recovered successfully.
Sun Aug 25 23:08:01 2024 - [info] 
Sun Aug 25 23:08:01 2024 - [info] * Phase 5: New master cleanup phase..
Sun Aug 25 23:08:01 2024 - [info] 
Sun Aug 25 23:08:01 2024 - [info] Resetting slave info on the new master..
Sun Aug 25 23:08:01 2024 - [info]  192.168.239.220: Resetting slave info succeeded.
Sun Aug 25 23:08:01 2024 - [info] Master failover to 192.168.239.220(192.168.239.220:3306) completed successfully.
Sun Aug 25 23:08:01 2024 - [info] 

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

app1: MySQL Master failover 192.168.239.210(192.168.239.210:3306) to 192.168.239.220(192.168.239.220:3306) succeeded

Master 192.168.239.210(192.168.239.210:3306) is down!

Check MHA Manager logs at docker-rhel for details.

Started manual(interactive) failover.
Selected 192.168.239.220(192.168.239.220:3306) as a new master.
192.168.239.220(192.168.239.220:3306): OK: Applying all logs succeeded.
192.168.239.230(192.168.239.230:3306): OK: Slave started, replicating from 192.168.239.220(192.168.239.220:3306)
192.168.239.220(192.168.239.220:3306): Resetting slave info succeeded.
Master failover to 192.168.239.220(192.168.239.220:3306) completed successfully.

恢复故障节点

bash 复制代码 
[root@mysql-01 ~]# systemctl start mysqld

查看SLAVE2发现并不会转回 master 1 MASTER 由 192.168.239.220 主机接管了

在MySQL - 1指定现在的 MASTER（MySQL-2） 并将自己设置为从

bash 复制代码 
stop slave;
reset slave all;
change master to
master_host='192.168.239.220',
master_user='repl',
master_password='Openlab123!',
master_auto_position=1;

故障之后会产生锁文件，不删除之后实验进行不了

bash 复制代码 
[root@docker-rhel ~]# rm -rf /etc/masterha/app1.failover.complete /etc/masterha/manager.log

3.7 MHA之自动切换

3.7.1 将MASTER切换回MySQL-1

bash 复制代码 
[root@docker-rhel masterha]# masterha_master_switch \
--conf=/etc/masterha/app1.cnf \
--master_state=alive \
--new_master_host=192.168.239.210 \
--new_master_port=3306 \
--orig_master_is_new_slave \
--running_updates_limit=10000
sql 复制代码 
############################## MASTER #############################
mysql> show master status\G
*************************** 1. row ***************************
             File: mysql-bin.000022
         Position: 194
     Binlog_Do_DB: 
 Binlog_Ignore_DB: 
Executed_Gtid_Set: abe58cad-6282-11ef-a9ac-000c29a51779:1-6,
d7f89afd-6282-11ef-ab48-000c299efdf0:1-5




############################## SLAVE-1 #############################

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.239.210
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000022
          Read_Master_Log_Pos: 194
               Relay_Log_File: mysql-02-relay-bin.000002
                Relay_Log_Pos: 367
        Relay_Master_Log_File: mysql-bin.000022
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes

############################## SLAVE-2 #############################

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.239.210
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000022
          Read_Master_Log_Pos: 194
               Relay_Log_File: mysql-03-relay-bin.000002
                Relay_Log_Pos: 367
        Relay_Master_Log_File: mysql-bin.000022
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes

3.7.2 开启自动切换功能 masterha_manager

  • 当主服务器发生故障时，**masterha_manager**会选择一个新的主服务器，并将所有从服务器的数据同步到新主服务器，从而保证数据的一致性和可用性。
bash 复制代码 
[root@docker-rhel masterha]# pwd
/etc/masterha
[root@docker-rhel masterha]# masterha_manager --conf=/etc/masterha/app1.cnf &

3.7.3 模拟故障停掉MASTER

bash 复制代码 
[root@mysql-01 ~]# systemctl stop mysqld

这个时候MySQL-1重新去启动的时候会发现不会顶替掉自动替换的MASTER（MASTER-2）,并且也不会自动切换到SLAVE状态-----> 这个时候需要我们手动去指定他

bash 复制代码 
[root@mysql-01 ~]# systemctl start mysqld
[root@mysql-01 ~]# mysql -uroot -pOpenlab123!
sql 复制代码 
mysql> change master to
       master_host='192.168.239.220',
       master_user='repl',
       master_password='Openlab123!',
       master_auto_position=1;

mysql> start slave;

mysql> show slave status\G

3.7.4 查看状态

3.8 MHA之 实现VIP****功能

3.8.1 什么是MHA的VIP功能

在我们重新设计之初指定的IP地址只有一个，不可能为了故障一个一个的去修改程序太麻烦，那样会显得非常地繁琐，在MHA中就有一个类似于keepalived的功能：VIP漂移
实验环境：

主从关系 节点 IP地址
MASTER MySQL-1 192.168.239.210
SLAVE-1 MySQL-2 192.168.239.220
SLAVE-2 MySQL-2 192.168.239.230

3.8.2 使用 perl 脚本实现的VIP漂移

主要的功能还是以perl语言来实现的

master_ip_failover -- 自动切换VIP漂移脚本

perl 复制代码 
#!/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 = '192.168.239.100/24';
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";
}

master_ip_online_change -- 手动切换VIP漂移脚本

perl 复制代码 
#!/usr/bin/env perl
use strict;  
use warnings FATAL =>'all';  
  
use Getopt::Long;  
  
my $vip = '192.168.239.100/24';
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";  
}

3.8.3 修改perl脚本关键参数

bash 复制代码 
# 自动切换VIP 的脚本
[root@docker-rhel masterha]# vim /usr/local/bin/master_ip_failover
bash 复制代码 
# 手动切换的脚本
[root@docker-rhel masterha]# vim /usr/local/bin/master_ip_online_change

3.8.4 赋予文件执行权限

bash 复制代码 
[root@docker-rhel masterha]# chmod +x /usr/local/bin/master_ip_failover 
[root@docker-rhel masterha]# chmod +x /usr/local/bin/master_ip_online_change

3.8.5 修改配置文件--指定脚本的路径

bash 复制代码 
[root@docker-rhel masterha]# vim /etc/masterha/app1.cnf

一开始在MASTER上必须要有VIP因为是指定这个IP拿这个IP进行程序通讯的

bash 复制代码 
[root@mysql-01 ~]# ip addr add 192.168.239.100/24 dev eth0

3.8.6 测试自动切换VIP漂移

启动自动调换 并实现VIP漂移

bash 复制代码 
[root@docker-rhel masterha]# masterha_manager --conf=/etc/masterha/app1.cnf &

停止MASTER（MySQL-1）

bash 复制代码 
[root@mysql-01 ~]# systemctl stop mysqld

查看日志

查看SLAVE-2(MySQL-3)

同样的在MySQL-1 端就算启动会发现他不会自动切换为slave

由于MySQL-2 为主需要MySQL-1做 SLAVE 指定MySQL-2

sql 复制代码 
mysql> change master to
       master_host='192.168.239.220',
       master_user='repl',
       master_password='Openlab123!',
       master_auto_position=1;

mysql> start slave;

3.8.7 手动切换 实现 VIP 漂移

手动切换的效果也是一样的--实现master_ip_online_change脚本

不过得删除锁文件--不然会出现错误

bash 复制代码 
[root@docker-rhel masterha]# rm -rf app1.failover.complete

手动切换到MySQL-1

bash 复制代码 
[root@docker-rhel masterha]# masterha_master_switch \
--conf=/etc/masterha/app1.cnf \
--master_state=alive \
--new_master_host=192.168.239.210 \
--new_master_port=3306 \
--orig_master_is_new_slave \
--running_updates_limit=10000

查看发现VIP已经漂移会来了

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