MHA之虚拟IP

在MySQL高可用之MHA部署这篇博文中，已经将MHA的基础架构部署完成，但是并没有解决一个虚拟IP的问题，因为当master宕机后，新的master顶上来，这时前端APP要连接的数据库IP已经发生了变化，为了解决这个问题，必然要引入虚拟IP，谈起虚拟IP，首先想到的应该是keepalived这个工具，但这个工具有个弊端，就是有一个脑裂的问题，所以更建议在生产中使用脚本的方式来控制这个VIP。

1、在manager节点写入此脚本

[root@manager scripts]# cat /scripts/master_ip_failover #!/usr/bin/env perluse 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 = '192.168.20.100';         #这里指定VIP地址my $key = '0';my $ssh_start_vip = "/sbin/ifconfig ens33:$key $vip";         #这条指令是启动VIPmy $ssh_stop_vip = "/sbin/ifconfig ens33:$key down";       #这条指令是停止VIPGetOptions( '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"; #`ssh $ssh_user\@cluster1 \" $ssh_start_vip \"`; exit 0; } else { &usage(); exit 1; }}# A simple system call that enable the VIP on the new mastersub start_vip() { `ssh $ssh_user\@$new_master_host \" $ssh_start_vip \"`;}# A simple system call that disable the VIP on the old_mastersub stop_vip() { return 0 unless ($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";}[root@manager ~]# ll /scripts/master_ip_failover             #需要保证脚本有可执行权限-rwxr-xr-x 1 root root 2006 2月  24 16:32 /scripts/master_ip_failover

2、修改manager配置文件

[root@manager ~]# cat /etc/masterha/app1.cnf           #配置文件指定脚本的位置[server default]manager_workdir=/var/log/masterha/app1manager_log=/var/log/masterha/app1/manager.loguser=managerpassword=123.comssh_user=rootrepl_user=mhareprepl_password=123.comping_interval=1master_ip_failover_script=/scripts/master_ip_failover     #增加改行，指定脚本的位置即可。[server1]hostname=192.168.20.2port=3306master_binlog_dir=/usr/local/mysql/datacandidate_master=1[server2]hostname=192.168.20.3port=3306master_binlog_dir=/usr/local/mysql/datacandidate_master=1[server3]hostname=192.168.20.4port=3306master_binlog_dir=/usr/local/mysql/datano_master=1

做到这里，就可以保证在切换master时，VIP地址也会随之切换到新的master主机上。