前言
- MHA目前在MySQL高可用方面是一个相对成熟的解决方案
- 但是在搭建的过程中会经常报错,且MHA的构建综合了主从复制,所以MHA的安装要思路清晰才可
一:MHA概述
1.1:什么是MHA?
- 日本DeNA公司 youshimaton(现就职于 Facebook公司)开发
- 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
- 支持故障切换
- 在MySQL故障切换过程中,MHA能做到在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能在最大程度上保证数据的一致性,以达到真正意义上的高可用
- MHA还提供在线主库切换的功能,能够安全地切换当前运行的主库到一个新的主库中(通过将从库提升为主库),大概0.5-2秒内即可完成
1.2:MHA的组成
- MHA Manager(管理节点)
- 用来接收外部信号,监控下方数据节点的工作状态
- MHA Node(数据节点)
- 工作的单位,负责具体的工作
1.3:MHA有什么特点?
- 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的不丢失
- 使用 MySQL55的半同步复制,可以大大降低数据丢失的风险
1.4:MHA形成的原因
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传统mysql主从架构存在单点故障的问题
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传统架构中,只有一个mysql主服务器,所以当出现单点故障的时候,整个服务器群集就会瘫痪掉
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为了解决这种情况,我们需要在主服务器宕机的时候,重新建立一台主服务器,负责监控等工作
二:MHA实验
2.1:实验环境
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VMware软件
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一台centos7作为MHA
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三台centos7作为mysql服务器
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搭建好mysql主从复制环境
没有搭建的可以看我之前的博客
https://blog.csdn.net/CN_TangZheng/article/details/103897251
2.2:拓扑图
2.3:实验目的
- 通过MHA监控MySQL数据库,在故障时自动进行切换,不影响业务
- 当主库失效时,备选主库自动成为主库
2.4:实验过程
- 因为操作系统是centos7,所以要下载MHA 0.57版本
2.4.1:安装gmake编译软件
[root@slave2 ~]# mount.cifs //192.168.11.11/ccc /mnt
Password for root@//192.168.11.11/ccc:
[root@slave2 ~]# cd /mnt/shuju数据库/mha
[root@slave2 mha]#
[root@slave2 mha]# tar zxvf cmake-2.8.6.tar.gz -C /opt
[root@slave2 mha]# cd /opt/cmake-2.8.6/
[root@slave2 cmake-2.8.6]# ./configure
[root@slave1 cmake-2.8.6]# gmake
[root@slave1 cmake-2.8.6]# gmake install
2.4.2:搭建mysql主从复制环境
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https://blog.csdn.net/CN_TangZheng/article/details/103897251
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记得关闭防火墙
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主从复制环境中的mysql同步的用户名为:myslave 密码:123456
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额外调整
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所有数据库授权mha用户对数据库的操作权限,每一个mysql数据库都要设置
'//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诵过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'; '//三台mysql服务器的授权增加一个给mha管理' mysql> grant all privileges on *.* to 'mha'@'192.168.79.%' identified by 'manager'; '//主备mysql服务器添加用户和权限' '//192.168.79.0段的从服务器拥有复制权限,可以使用myslave身份123456密码复制所有的库和表' mysql> GRANT REPLICATION SLAVE ON *.* TO 'myslave'@'192.168.79.%' IDENTIFIED BY '123456';
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slave1和slave2两个从数据库设置为只读
mysql> set global read_only=1;
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所有slave节点配置二进制日志,注释掉client段的默认字符集
[root@slave1 ~]# vim /etc/my.cnf [mysqld]段落添加 log-bin=slave1-bin '//添加二进制日志' 所以slave节点都要配置,我就不一一展示了 '//从服务器上都注释掉client段的默认字符集' [root@slave1 ~]# vim /etc/my.cnf [client] #default-character-set=utf8 '//注释掉此'
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创建软连接
所有节点创建软连接 ln -s /usr/local/mysql/bin/mysqlbinlog /usr/local/bin/ 创建mysql软连接 ln -s /usr/local/mysql/bin/mysql /usr/local/bin/
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2.4.3:所有节点安装环境和Node组件和Manager组件
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所有服务器上都要安装mha依赖的环境,此处仅展示mha_manager的安装
[root@mha_manager ~]# yum install epel-release --nogpgcheck -y [root@mha_manager ~]# yum install -y perl-DBD-MySQL \ perl-Config-Tiny \ perl-Log-Dispatch \ perl-Parallel-ForkManager \ perl-ExtUtils-CBuilder \ perl-ExtUtils-MakeMaker \ perl-CPAN
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所有服务器都安装安装node组件,此处仅展示master服务器的安装
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[root@master ~]# tar zxvf /mnt/shuju数据库/mha/mha4mysql-node-0.57.tar.gz [root@master ~]# cd mha4mysql-node-0.57/ [root@master mha4mysql-node-0.57]# yum install perl-Module-Install -y [root@master mha4mysql-node-0.57]# perl Makefile.PL ==> Auto-install the 1 mandatory module(s) from CPAN? [y] y '//输入y' [root@master mha4mysql-node-0.57]# make [root@master mha4mysql-node-0.57]# make install
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仅mha_manager服务器安装manager组件
[root@mha_manager ~]# tar zxvf /mnt/shuju数据库/mha/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 [root@mha_manager mha4mysql-manager-0.57]# make install
2.4.4:配置节点间SSH面交互登陆
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mha_manager主机配置到所有数据库节点的密钥对验证
[root@mha_manager ~]# ssh-keygen -t rsa '//创建非对称密钥对' '//因为想要免密登陆,所以三个都直接回车就行,不需要设置密码' Enter file in which to save the key (/root/.ssh/id_rsa): Enter passphrase (empty for no passphrase): Enter same passphrase again: '//上传秘钥到节点服务器' [root@mha_manager ~]# ssh-copy-id 192.168.79.134 Are you sure you want to continue connecting (yes/no)? yes [email protected]'s password: //输入密码' '//相同方法建立其他服务器' [root@mha_manager ~]# ssh-copy-id 192.168.79.135 [root@mha_manager ~]# ssh-copy-id 192.168.79.136
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在master上配置到数据库节点slave1和slave2的免密验证
[root@master mha4mysql-node-0.57]# ssh-keygen -t rsa '//创建非对称密钥对' '//用上述方法建立其他服务器' [root@master mha4mysql-node-0.57]# ssh-copy-id 192.168.79.135 [root@master mha4mysql-node-0.57]# ssh-copy-id 192.168.79.136
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在slave1上配置到数据库节点master和slave2的免密验证
[root@slave1 ~]# ssh-keygen -t rsa [root@slave1 ~]# ssh-copy-id 192.168.79.134 [root@slave1 ~]# ssh-copy-id 192.168.79.136
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在slave2上配置到数据库节点master和slave1的免密验证
[root@slave2 ~]# ssh-keygen -t rsa [root@slave2 ~]# ssh-copy-id 192.168.79.134 [root@slave2 ~]# ssh-copy-id 192.168.79.135
2.4.5:配置MHA-Manager组件
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复制相关脚本到/usr/local/bin目录
[root@mha_manager ~]# cp -ra /root/mha4mysql-manager-0.57/samples/scripts /usr/local/bin [root@mha_manager samples]# ls -l /usr/local/bin/scripts/ -rwxr-xr-x. 1 1001 1001 3648 5月 31 2015 master_ip_failover 自动切换时 VIP管理的脚本 -rwxr-xr-x. 1 1001 1001 9870 5月 31 2015 master_ip_online_change 在线切换VIP的管理 -rwxr-xr-x. 1 1001 1001 11867 5月 31 2015 power_manager 故障发生后关闭主机的脚本 -rwxr-xr-x. 1 1001 1001 1360 5月 31 2015 send_report 因故障切换后发送报警的脚本 [root@mha_manager ~]# cp /usr/local/bin/scripts/master_ip_failover /usr/local/bin/ '//自动切换时 VIP管理的脚本'
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修改master_ip_failover 脚本
[root@mha_manager ~]# vim /usr/local/bin/master_ip_failover '//删除内容,重新编写脚本' #!/usr/bin/env perl '//第一行要最顶行写,不要有空格' 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 = '192.168.79.100'; my $brdc = '192.168.79.255'; 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"; }
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创建MHA软件目录并拷贝配置文件
[root@mha_manager ~]# mkdir /etc/masterha [root@mha_manager ~]# cp /root/mha4mysql-manager-0.57/samples/conf/app1.cnf /etc/masterha/ [root@mha_manager ~]# vim /etc/masterha/app1.cnf '//删除内容,重新编写脚本' [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=123456 repl_user=myslave secondary_check_script=/usr/local/bin/masterha_secondary_check -s 192.168.79.135 -s 192.168.79.136 shutdown_script="" ssh_user=root user=mha [server1] hostname=192.168.79.134 port=3306 [server2] candidate_master=1 hostname=192.168.79.135 check_repl_delay=0 port=3306 [server3] hostname=192.168.79.136 port=3306
2.4.6:测试SSH与mysql主从连接
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验证密钥对
[root@mha_manager ~]# masterha_check_ssh -conf=/etc/masterha/app1.cnf Fri Jan 10 01:14:10 2020 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping. Fri Jan 10 01:14:10 2020 - [info] Reading application default configuration from /etc/masterha/app1.cnf.. Fri Jan 10 01:14:10 2020 - [info] Reading server configuration from /etc/masterha/app1.cnf.. Fri Jan 10 01:14:10 2020 - [info] Starting SSH connection tests.. Fri Jan 10 01:14:11 2020 - [debug] Fri Jan 10 01:14:10 2020 - [debug] Connecting via SSH from [email protected].135(192.168.79.135:22) to [email protected].136(192.168.79.136:22).. Fri Jan 10 01:14:11 2020 - [debug] ok. Fri Jan 10 01:14:12 2020 - [debug] Fri Jan 10 01:14:10 2020 - [debug] Connecting via SSH from [email protected].136(192.168.79.136:22) to [email protected].135(192.168.79.135:22).. Fri Jan 10 01:14:11 2020 - [debug] ok. Fri Jan 10 01:14:12 2020 - [info] All SSH connection tests passed successfully.
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测试mysql主从连接
[root@mha_manager ~]# masterha_check_repl -conf=/etc/masterha/app1.cnf
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相关报错,请查阅我的博客
https://blog.csdn.net/CN_TangZheng/article/details/103925515
2.4.7:配置虚拟IP,启动MHA
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添加虚拟IP
[root@master ~]# /sbin/ifconfig ens33:1 192.168.79.100/24
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启动MHA
[root@mha_manager ~]# nohup masterha_manager --conf=/etc/masterha/app1.cnf --remove_dead_master_conf --ignore_last_failover < /dev/null > [root@mha_manager ~]# /var/log/masterha/app1/manager.log 2>&1 & '//查看到当前的master节点是谁' [root@mha_manager ~]# masterha_check_status --conf=/etc/masterha/app1.cnf '//查看当前日志信息' [root@mha_manager ~]# cat /var/log/masterha/app1/manager.log
2.4.8:模拟故障
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启动监控观察日志记录
[root@mha_manager ~]# tailf /var/log/masterha/app1/manager.log
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关掉master服务器
[root@master ~]# pkill -9 mysqld
2.5:实验验证
2.5.1:主服务器变更成功
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此时发现主服务器已经变更
slave1查看
[root@slave1 ~]# ifconfig ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.79.135 netmask 255.255.255.0 broadcast 192.168.79.255 inet6 fe80::159a:a8d1:5769:74d0 prefixlen 64 scopeid 0x20<link> ether 00:0c:29:34:57:c1 txqueuelen 1000 (Ethernet) RX packets 347068 bytes 28229347 (26.9 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 528201 bytes 67755670 (64.6 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 ens33:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.79.100 netmask 255.255.255.0 broadcast 192.168.79.255 ether 00:0c:29:34:57:c1 txqueuelen 1000 (Ethernet)
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mha_manager查看
'//会动态显示后续信息' Generating relay diff files from the latest slave succeeded. 192.168.79.136(192.168.79.136:3306): OK: Applying all logs succeeded. Slave started, replicating from 192.168.79.135(192.168.79.135:3306) 192.168.79.135(192.168.79.135:3306): Resetting slave info succeeded. Master failover to 192.168.79.135(192.168.79.135:3306) completed successfully.
2.5.2:尝试从客户端通过虚拟IP连接上数据库
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直接在mha_manager上安装mysql
[root@mha_manager ~]# yum install mysql -y
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在vip的数据库服务器上提取
[root@slave1 ~]# mysql -uroot -p Enter password: mysql> grant all on *.* to 'root'@'%' identified by 'abc123';
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在客户机(mha_manager)上用虚拟IP进行登录
[root@mha_manager ~]# mysql -h 192.168.79.100 -uroot -pabc123 MySQL [(none)]> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | yiku | | mysql | | performance_schema | | erku | | sanku | | sys | +--------------------+ 8 rows in set (0.00 sec)