MySQL 搭建MHA架构部署的步骤

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MAH

一：MAH架构介绍

MHA (Master High Availability)目前在MySQL高可用方面是一个相对成熟的解决方案，它由日本人youshimaton开发，是一套优秀的作为MySQL高可用性环境下故障切换和主从提升的高可用软件。在MySQL故障切换过程中，MHA能做到0~30秒之内自动完成数据库的故障切换操作，并且在进行故障切换的过程中，MHA能最大程度上保证数据库的一致性，以达到真正意义上的高可用。
MHA由两部分组成:MHA Manager (管理节点)和MHANode(数据节点)。MHA Manager可以独立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上。当Master 出现故障是，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。整个故障转移过程对应用程序是完全透明的。

二：适用场景

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 ,一台充当备用Master，另一台充当从库。出于成本考虑，淘宝在此基础上进行了改造，目前淘宝开发的 TMHA 已经支持一主一从。

三：MHA工作原理

1.从宕机崩溃的 Master保存二进制日志事件(binlog event) ;

2.识别含有最新更新的Slave;

3.应用差异的中继日志(relay log)到其他Slave;

4.应用从 Master 保存的二进制日志事件;

5.提升—个 Slave为新的Master;

6.使其他的 Slave 连接新的 Master 进行复制;

四：MHA的组成

Manager工具包
Node工具包

1：Manager工具包

masterha_check_ssh:检查MHA的 SSH配置情况
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(自动或手动)
masterha_conf_host:添加或删除配置的server 信息

2：Node工具包

通常由MHA Manager的脚本触发，无需人工操作

save_binary_logs:保存和复制Master 的 binlog日志
apply_diff_relay_logs:识别差异的中级日志时间并将其应用到其他 Slave
filter_mysqlbinlog:去除不必要的ROOLBACK事件（已经废弃)
purge_relay_logs:清除中继日志（不阻塞SQL线程)

五：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

MHA 架构部署

一：拓扑图

二：数据库安装

MySQL 版本使用 5.6.36、cmake 版本使用 2.8.6

1：安装编译依赖的环境

[root@master ~]# yum -y install ncurses-devel gcc-c++ perl-Module-Install

2.：安装 gmake 编译软件

[root@master ~]# tar zxvf cmake-2.8.6.tar.gz
[root@master ~]# cd cmake-2.8.6
[root@master cmake-2.8.6]# ./configure
[root@master cmake-2.8.6]# gmake && gmake install

3：安装 MySQL 数据库

[root@master ~]# tar -zxvf mysql-5.6.36.tar.gz
[root@master ~]# cd mysql-5.6.36
[root@master mysql-5.6.36]# cmake -DCMAKE_INSTALL_PREFIX=/usr/local/mysql -DDEFAULT_CHARSET=utf8 -DDEFAULT_COLLATION=utf8_general_ci -DWITH_EXTRA_CHARSETS=all -DSYSCONFDIR=/etc
[root@master mysql-5.6.36]# make && make install
[root@master mysql-5.6.36]# cp support-files/my-default.cnf /etc/my.cnf
[root@master mysql-5.6.36]# cp support-files/mysql.server /etc/rc.d/init.d/mysqld
[root@master ~]# chmod +x /etc/rc.d/init.d/mysqld
[root@master ~]# chkconfig --add mysqld
[root@master ~]# echo "PATH=$PATH:/usr/local/mysql/bin" >> /etc/profile
[root@master ~]# source /etc/profile
chown -R mysql.mysql /usr/local/mysql groupadd mysql
[root@master ~]# useradd -M -s /sbin/nologin mysql -g mysql
[root@master ~]# chown -R mysql.mysql /usr/local/mysql
[root@master ~]# mkdir -p /data/mysql
[root@master ~]# /usr/local/mysql/scripts/mysql_install_db --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data --user=mysql

4：修改 Master 的主配置文件/etc/my.cnf 文件

将原来配置全部删除

[root@master ~]# vi /etc/my.cnf
[client]
port = 3306
socket = /usr/local/mysql/mysql.sock

[mysql]
port = 3306
socket = /usr/local/mysql/mysql.sock

[mysqld]
user = mysql
basedir = /usr/local/mysql
datadir = /usr/local/mysql/data
port = 3306
pid-file = /usr/local/mysql/mysqld.pid
socket = /usr/local/mysql/mysql.sock
server-id = 1
log_bin = master-bin
log-slave-updates = true

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_AUTO_VALUE_ON_ZERO,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,PIPES_AS_CONCAT,ANSI_QUOTES

另外两台 slave 数据库

三台服务器的 server-id 不能一样，其余一样正常写入

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

server-id = 3
log_bin = master-bin
relay-log = relay-log-bin 
relay-log-index = slave-relay-bin.index

5：三台数据库分别做两个软链接，软链接是为 HMA 服务的

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

6：三台数据库启动 MySQL

[root@master ~]# /usr/local/mysql/bin/mysqld_safe --user=mysql &
[root@master ~]# service mysqld restart 
Shutting down MySQL.. SUCCESS! 
Starting MySQL. SUCCESS!

三：数据库配置主从同步

登录数据库

[root@master ~]# mysql

1：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> grant replication slave on *.* to 'myslave'@'20.0.0.%' identified by '123';
mysql> grant all privileges on *.* to 'mha'@'20.0.0.%' identified by 'manager';
mysql> flush privileges;

2：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> grant all privileges on *.* to 'mha'@'master' identified by 'manager';
mysql> grant all privileges on *.* to 'mha'@'slave1' identified by 'manager';
mysql> grant all privileges on *.* to 'mha'@'slave2' identified by 'manager';

3：在 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 |  608 |    |     |     |
+-------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

4：在 slave1 和 slave2 分别执行同步

mysql> change master to master_host='20.0.0.10',master_user='myslave',master_password='123',master_log_file='master-bin.000001',master_log_pos=608
mysql> start slave;

5：查看 IO 和 SQL 线程都是 yes 代表同步是否正常

mysql> show slave status\G;
*************************** 1. row ***************************
    Slave_IO_State: Waiting for master to send event
     Master_Host: 20.0.0.10
     Master_User: myslave
     Master_Port: 3306
    Connect_Retry: 60
    Master_Log_File: master-bin.000001
   Read_Master_Log_Pos: 608
    Relay_Log_File: relay-log-bin.000002
    Relay_Log_Pos: 284
  Relay_Master_Log_File: master-bin.000001
    Slave_IO_Running: Yes
   Slave_SQL_Running: Yes
    Replicate_Do_DB: 
   Replicate_Ignore_DB:

必须设置两个从库为只读模式

mysql> set global read_only=1;

6：在 master 主库插入两条数据，测试是否同步

mysql> create database test_db;
Query OK, 1 row affected (0.00 sec)
mysql> use test_db;
Database changed
mysql> create table test(id int);
Query OK, 0 rows affected (0.13 sec)
mysql> insert into test(id) values (1);
Query OK, 1 row affected (0.03 sec)

7：在两个从库分别查询如下所示说明主从同步正常

mysql> select * from test_db.test;
+------+
| id |
+------+
| 1 |
+------+
1 row in set (0.00 sec)

四：安装 MHA 软件

1：所有服务器上都安装 MHA 依赖的环境，首先安装 epel 源（3+1）

[root@master ~]# cd /etc/yum.repos.d/
[root@master yum.repos.d]# ll
总用量 20
drwxr-xr-x. 2 root root 187 10月 10 18:08 backup
-rw-r--r--. 1 root root 1458 12月 28 23:07 CentOS7-Base-163.repo
-rw-r--r--. 1 root root 951 12月 29 14:52 epel.repo
-rw-r--r--. 1 root root 1050 11月 1 04:33 epel.repo.rpmnew
-rw-r--r--. 1 root root 1149 11月 1 04:33 epel-testing.repo
-rw-r--r--. 1 root root 228 10月 27 18:43 local.repo

三台数据库加上一台 mha-manager

[root@mha-manager ~]# yum install epel-release --nogpgcheck
[root@mha-manager ~]# yum install -y perl-DBD-MySQL perl-Config-Tiny perl-Log-Dispatch perl-ParalExtUtils-CBuilder perl-ExtUtils-MakeMaker perl-CPAN

2：在所有服务器上必须先安装 node 组件（3+1）

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

3：在 mha-manager 上安装 manager 组件

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

manager 安装后在/usr/local/bin 下面会生成几个工具

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 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

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）

五：配置无密码认证

1：在 manager 上配置到所有节点的无密码认证

（1）生成密钥

[root@mha-manager ~]# ssh-keygen -t rsa     # 一直回车

（2）生成密钥之后发送给其他3个数据库

[root@mha-manager ~]# ssh-copy-id 20.0.0.10  # 输入：yes 密码：123456
[root@mha-manager ~]# ssh-copy-id 20.0.0.11
[root@mha-manager ~]# ssh-copy-id 20.0.0.12

（3）登录测试

[root@mha-manager ~]# ssh [email protected]
Last login: Tue Dec 29 14:52:09 2020 from 20.0.0.1
[root@master ~]# exit
登出
Connection to 20.0.0.10 closed.
[root@mha-manager ~]# ssh [email protected]
Last login: Tue Dec 29 13:20:07 2020 from 20.0.0.1
[root@slave1 ~]# exit
登出
Connection to 20.0.0.11 closed.
[root@mha-manager ~]# ssh [email protected]
Last login: Tue Oct 27 19:45:24 2020 from 20.0.0.1
[root@slave2 ~]# exit
登出
Connection to 20.0.0.12 closed.

2：在 master 上配置到数据库节点的无密码认证

（1）生成密钥

[root@master ~]# ssh-keygen -t rsa

（2）生成密钥之后发送给其他2个数据库

[root@master ~]# ssh-copy-id 20.0.0.11
[root@master ~]# ssh-copy-id 20.0.0.12

（3）登录测试

[root@master ~]# ssh [email protected]
Last login: Tue Dec 29 16:40:06 2020 from 20.0.0.13
[root@slave1 ~]# exit
登出
Connection to 20.0.0.11 closed.
[root@master ~]# ssh [email protected]
Last login: Tue Oct 27 23:05:20 2020 from 20.0.0.13
[root@slave2 ~]# exit
登出
Connection to 20.0.0.12 closed.

3：在 slave1 上配置到数据库节点的无密码认证

（1）生成密钥

[root@slave1 ~]# ssh-keygen -t rsa

（2）生成密钥之后发送给其他2个数据库

[root@slave1 ~]# ssh-copy-id 20.0.0.10
[root@slave1 ~]# ssh-copy-id 20.0.0.12

（3）登录测试

[root@slave1 ~]# ssh [email protected]
Last login: Tue Dec 29 16:39:55 2020 from 20.0.0.13
[root@master ~]# exit
登出
Connection to 20.0.0.10 closed.
[root@slave1 ~]# ssh [email protected]
Last login: Tue Oct 27 23:14:06 2020 from 20.0.0.10
[root@slave2 ~]# exit
登出
Connection to 20.0.0.12 closed.

4：在 slave2 上配置到数据库节点的无密码认证

（1）生成密钥

[root@slave2 ~]# ssh-keygen -t rsa

（2）生成密钥之后发送给其他2个数据库

[root@slave2 ~]# ssh-copy-id 20.0.0.10
[root@slave2 ~]# ssh-copy-id 20.0.0.11

（3）登录测试

[root@slave2 ~]# ssh [email protected]
Last login: Tue Dec 29 16:59:43 2020 from 20.0.0.11
[root@master ~]# exit
登出
Connection to 20.0.0.10 closed.
[root@slave2 ~]# ssh [email protected]
Last login: Tue Dec 29 16:48:51 2020 from 20.0.0.10
[root@slave1 ~]# exit
登出
Connection to 20.0.0.11 closed.

六：配置 MHA

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

（1）拷贝

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

（2）拷贝后会有四个执行文件

master_ip_failover #自动切换时 VIP 管理的脚本

master_ip_online_change #在线切换时 vip 的管理

power_manager #故障发生后关闭主机的脚本

send_report #因故障切换后发送报警的脚本

（3）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-manager scripts]# cp master_ip_failover /usr/local/bin/
[root@mha-manager scripts]# cd ..
[root@mha-manager bin]# ll
总用量 88

2：修改自动切换脚本

[root@mha-manager ~]# vi /usr/local/bin/master_ip_failover  # 删除里面所有内容
#!/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 = '20.0.0.200';
my $brdc = '20.0.0.255';
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";
}

3：创建 MHA 软件目录并拷贝配置文件

[root@mha-manager ~]# mkdir /etc/mha
[root@mha-manager ~]# cp mha4mysql-manager-0.57/samples/conf/app1.cnf /etc/mha
[root@mha-manager ~]# vi /etc/mha/app1.cnf
[server default]
manager_workdir=/var/log/masterha/app1
manager_log=/var/log/masterha/app1/manager.log
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
user=mha
ping_interval=1
remote_workdir=/tmp
repl_password=123
repl_user=myslave
secondary_check_script=/usr/local/bin/masterha_secondary_check -s 20.0.0.11 -s 20.0.0.12
shutdown_script=""
ssh_user=root

[server1]
hostname=20.0.0.10
port=3306
[server2]
hostname=20.0.0.11
port=3306
candidate_master=1
check_repl_delay=0
[server3]
hostname=20.0.0.12
port=3306

七：健康检查

1：测试 ssh 无密码认证，如果正常最后会输出 successfully

[root@mha-manager ~]# masterha_check_ssh
--conf=<server_config_file> must be set.
[root@mha-manager ~]# masterha_check_ssh --conf=/etc/mha/app1.cnf
Tue Dec 29 20:19:16 2020 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Tue Dec 29 20:19:16 2020 - [info] Reading application default configuration from /etc/mha/app1.cnf..
Tue Dec 29 20:19:16 2020 - [info] Reading server configuration from /etc/mha/app1.cnf..
Tue Dec 29 20:19:16 2020 - [info] Starting SSH connection tests..
Tue Dec 29 20:19:17 2020 - [debug] 
Tue Dec 29 20:19:16 2020 - [debug] Connecting via SSH from [email protected](20.0.0.10:22) to [email protected](20.0.0.11:22)..
Tue Dec 29 20:19:16 2020 - [debug] ok.
Tue Dec 29 20:19:16 2020 - [debug] Connecting via SSH from [email protected](20.0.0.10:22) to [email protected](20.0.0.12:22)..
Tue Dec 29 20:19:17 2020 - [debug] ok.
Tue Dec 29 20:19:18 2020 - [debug] 
Tue Dec 29 20:19:17 2020 - [debug] Connecting via SSH from [email protected](20.0.0.12:22) to [email protected](20.0.0.10:22)..
Tue Dec 29 20:19:17 2020 - [debug] ok.
Tue Dec 29 20:19:17 2020 - [debug] Connecting via SSH from [email protected](20.0.0.12:22) to [email protected](20.0.0.11:22)..
Tue Dec 29 20:19:18 2020 - [debug] ok.
Tue Dec 29 20:19:18 2020 - [debug] 
Tue Dec 29 20:19:16 2020 - [debug] Connecting via SSH from [email protected](20.0.0.11:22) to [email protected](20.0.0.10:22)..
Tue Dec 29 20:19:17 2020 - [debug] ok.
Tue Dec 29 20:19:17 2020 - [debug] Connecting via SSH from [email protected](20.0.0.11:22) to [email protected](20.0.0.12:22)..
Tue Dec 29 20:19:17 2020 - [debug] ok.
Tue Dec 29 20:19:18 2020 - [info] All SSH connection tests passed successfully.

2：测试 MySQL 主从连接情况，最后出现 MySQL Replication Health is OK 字样说明

[root@mha-manager ~]# masterha_check_repl --conf=/etc/mha/app1.cnf
Tue Dec 29 20:30:29 2020 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Tue Dec 29 20:30:29 2020 - [info] Reading application default configuration from /etc/mha/app1.cnf..
Tue Dec 29 20:30:29 2020 - [info] Reading server configuration from /etc/mha/app1.cnf..
Tue Dec 29 20:30:29 2020 - [info] MHA::MasterMonitor version 0.57.
Tue Dec 29 20:30:30 2020 - [info] GTID failover mode = 0
Tue Dec 29 20:30:30 2020 - [info] Dead Servers:
Tue Dec 29 20:30:30 2020 - [info] Alive Servers:
Tue Dec 29 20:30:30 2020 - [info] 20.0.0.10(20.0.0.10:3306)
Tue Dec 29 20:30:30 2020 - [info] 20.0.0.11(20.0.0.11:3306)
Tue Dec 29 20:30:30 2020 - [info] 20.0.0.12(20.0.0.12:3306)
Tue Dec 29 20:30:30 2020 - [info] Alive Slaves:
Tue Dec 29 20:30:30 2020 - [info] 20.0.0.11(20.0.0.11:3306) Version=5.6.36-log (oldest major version between slaves) log-bin:enabled
.......省略
Checking the Status of the script.. OK 
Tue Dec 29 20:30:55 2020 - [info] OK.
Tue Dec 29 20:30:55 2020 - [warning] shutdown_script is not defined.
Tue Dec 29 20:30:55 2020 - [info] Got exit code 0 (Not master dead).

MySQL Replication Health is OK.

八：查看 master1 的 VIP 地址

查看 20.0.0.200 是否存在

这个 VIP 地址不会因为manager 节点停止 MHA 服务而消失

第一次启动mha，主库上并不会主动的生成vip地址，需要手动开启

[root@master ~]# ifconfig ens33:1 20.0.0.200/24 up
[root@master ~]# ip addr
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
 link/ether 00:0c:29:8d:e2:af brd ff:ff:ff:ff:ff:ff
 inet 20.0.0.10/24 brd 20.0.0.255 scope global ens33
  valid_lft forever preferred_lft forever
 inet 20.0.0.200/24 brd 20.0.0.255 scope global secondary ens33:1
  valid_lft forever preferred_lft forever
 inet6 fe80::a6c1:f3d4:160:102a/64 scope link 
  valid_lft forever preferred_lft forever

九：启动 MHA 并查看状态

[root@mha-manager ~]# nohup masterha_manager --conf=/etc/mha/app1.cnf --remove_dead_master_conf --ignore_last_failover < /dev/null > /var/log/masterha/app1/manager.log 2>&1 &
[1] 57152
[root@mha-manager ~]# masterha_check_status --conf=/etc/mha/app1.cnf
app1 (pid:57152) is running(0:PING_OK), master:20.0.0.10

故障模拟与修复

一：故障模拟

1：将 master 主服务器 down 掉

[root@master ~]# pkill mysqld

2：查看日志信息

[root@mha-manager ~]# cat /var/log/masterha/app1/manager.log

master 20.0.0.10(20.0.0.10:3306) is down!  # 20.0.0.10 以停掉

Check MHA Manager logs at mha-manager:/var/log/masterha/app1/manager.log for details.

Started automated(non-interactive) failover.
Invalidated master IP address on 20.0.0.10(20.0.0.10:3306)
The latest slave 20.0.0.11(20.0.0.11:3306) has all relay logs for recovery.
Selected 20.0.0.11(20.0.0.11:3306) as a new master.  # 20.0.0.11 成为主服务器
20.0.0.11(20.0.0.11:3306): OK: Applying all logs succeeded.
20.0.0.11(20.0.0.11:3306): OK: Activated master IP address.
20.0.0.12(20.0.0.12:3306): This host has the latest relay log events.
Generating relay diff files from the latest slave succeeded.

3：查看虚拟地址

虚拟地址已到 20.0.0.11 上面

[root@slave1 ~]# ip addr
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
 link/ether 00:0c:29:49:77:39 brd ff:ff:ff:ff:ff:ff
 inet 20.0.0.11/24 brd 20.0.0.255 scope global ens33
  valid_lft forever preferred_lft forever
 inet 20.0.0.200/8 brd 20.255.255.255 scope global ens33:1
  valid_lft forever preferred_lft forever
 inet6 fe80::5cbb:1621:4281:3b24/64 scope link 
  valid_lft forever preferred_lft forever

4：查看主从状态

查看主服务器的二进制文件

[root@slave1 ~]# mysql

mysql> show master status;
+-------------------+----------+--------------+------------------+-------------------+
| File    | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------------+----------+--------------+------------------+-------------------+
| master-bin.000003 |  120 |    |     |     |
+-------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

查看从2的状态

[root@slave2 ~]# mysql

mysql> show slave status\G;
*************************** 1. row ***************************
    Slave_IO_State: Waiting for master to send event
     Master_Host: 20.0.0.11
     Master_User: myslave
     Master_Port: 3306
    Connect_Retry: 60
    Master_Log_File: master-bin.000003
   Read_Master_Log_Pos: 120
    Relay_Log_File: relay-log-bin.000002
    Relay_Log_Pos: 284
  Relay_Master_Log_File: master-bin.000003
    Slave_IO_Running: Yes
   Slave_SQL_Running: Yes
    Replicate_Do_DB: 
   Replicate_Ignore_DB:

二：故障修复

1：开启 down 掉的数据库

[root@master ~]# systemctl start mysqld
[root@master ~]# systemctl status mysqld
● mysqld.service - LSB: start and stop MySQL
 Loaded: loaded (/etc/rc.d/init.d/mysqld; bad; vendor preset: disabled)
 Active: active (running) since 二 2020-12-29 21:50:03 CST; 25s ago
  Docs: man:systemd-sysv-generator(8)
 Process: 977 ExecStart=/etc/rc.d/init.d/mysqld start (code=exited, status=0/SUCCESS)
 CGroup: /system.slice/mysqld.service
   ├─1026 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/usr/local/mysql/data --pid-fi...
   └─1358 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/usr/local/m

2：down 掉的数据库进行主从复制

主从复制

[root@master ~]# mysql

mysql> change master to master_host='20.0.0.11',master_user='myslave',master_password='123',master_log_file='master-bin.000003',master_log_pos=120; 
Query OK, 0 rows affected, 2 warnings (0.01 sec)
# 20.0.0.11 是主服务器 down 掉之后成为的主服务器

mysql> start slave;
Query OK, 0 rows affected (0.01 sec)

查看状态

mysql> show slave status\G;
*************************** 1. row ***************************
    Slave_IO_State: Waiting for master to send event
     Master_Host: 20.0.0.11
     Master_User: myslave
     Master_Port: 3306
    Connect_Retry: 60
    Master_Log_File: master-bin.000003
   Read_Master_Log_Pos: 120
    Relay_Log_File: mysqld-relay-bin.000002
    Relay_Log_Pos: 284
  Relay_Master_Log_File: master-bin.000003
    Slave_IO_Running: Yes
   Slave_SQL_Running: Yes
    Replicate_Do_DB: 
   Replicate_Ignore_DB:

3：修改 mha 配置文件

[root@mha-manager ~]# vi /etc/mha/app1.cnf

secondary_check_script=/usr/local/bin/masterha_secondary_check -s 20.0.0.10 -s 20.0.0.12
# 由于 20.0.0.11 成为主服务器，所以要添加 20.0.0.10 和 20.0.0.12 为从服务器
[server1]
hostname=20.0.0.10
candidate_master=1
check_repl_delay=0
port=3306
[server2]
hostname=20.0.0.11
port=3306
# 由于 20.0.0.10 down 掉，所以 server1 文件自动删除，重新添加 server1，并设为备选主服务器，server2 修改

4：进入数据库重新授权

[root@master ~]# mysql

mysql> grant all privileges on *.* to 'mha'@'master' identified by 'manager';
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

5：再次启动 mha

[root@mha-manager ~]# nohup masterha_manager --conf=/etc/mha/app1.cnf --remove_dead_master_conf --ignore_last_failover < /dev/null > /var/log/masterha/app1/manager.log 2>&1 &
[1] 58927
[root@mha-manager ~]# masterha_check_status --conf=/etc/mha/app1.cnf
app1 (pid:58927) is running(0:PING_OK), master:20.0.0.11

6：再次查看日志

[root@mha-manager ~]# cat /var/log/masterha/app1/manager.log
......
Tue Dec 29 22:16:53 2020 - [info] Dead Servers:  # 停掉的服务
Tue Dec 29 22:16:53 2020 - [info] Alive Servers:  # 存活的服务
Tue Dec 29 22:16:53 2020 - [info] 20.0.0.10(20.0.0.10:3306)
Tue Dec 29 22:16:53 2020 - [info] 20.0.0.11(20.0.0.11:3306)
Tue Dec 29 22:16:53 2020 - [info] 20.0.0.12(20.0.0.12:3306)
.......

7：主数据库写入数据同步并查看

其他数据库都可以查到

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

mysql> show databases;
+--------------------+
| Database   |
+--------------------+
| information_schema |
| mysql    |
| ooo    |
| performance_schema |
| test    |
| test_db   |
+--------------------+
6 rows in set (0.00 sec)

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