MHA VIP切换脚本

    MHA能够在10~30秒内实现自动故障检测和故障转移，适用于对高可用性，数据完整性要求较高的场合。要做到无缝切换，还需要依赖于VIP漂移。VIP漂移比较常用的方式为使用keepalived或者使用脚本直接实现。脚本方式无须安装及复杂配置，相对简单。本文描述了基于脚本实现VIP切换。

  对于keepalived的相关配置可以参考：CentOS 5.9下安装配置keepalived

1、当前主机环境及MHA配置   [root@vdbsrv1 ~]# more /etc/hosts 127.0.0.1    localhost.localdomain localhost 192.168.1.6  vdbsrv1  #master 192.168.1.7  vdbsrv2  #slave1 192.168.1.8  vdbsrv3  #slave2 192.168.1.12 vdbsrv4  #manager

###os环境 [root@vdbsrv4 ~]# more /etc/issue CentOS release 5.9 (Final) Kernel \r on an \m

###mysql环境 [root@vdbsrv4 ~]# mysql -e "show variables like 'version'" +---------------+------------+ | Variable_name | Value      | +---------------+------------+ | version       | 5.6.22-log | +---------------+------------+

[root@vdbsrv4 ~]# masterha_manager --version masterha_manager version 0.56.

###MHA配置信息 [root@vdbsrv4 ~]$ more /etc/masterha/app1.cnf [server default] manager_workdir=/var/log/masterha/app1 manager_log=/var/log/masterha/app1/manager.log

user=mha password=xxx ssh_user=root repl_user=repl   repl_password=repl   ping_interval=1 shutdown_script="" master_ip_online_change_script="" report_script="" master_ip_failover_script=/tmp/master_ip_failover [server1] hostname=vdbsrv1 master_binlog_dir=/data/mysqldata

[server2] hostname=vdbsrv2 master_binlog_dir=/data/mysqldata

[server3] hostname=vdbsrv3 master_binlog_dir=/data/mysqldata/ #candidate_master=1

2、测试VIP切换 ###测试VIP(192.168.1.13)是否被启用 [root@vdbsrv4 ~]# ping 192.168.1.13 PING 192.168.1.13 (192.168.1.13) 56(84) bytes of data. From 192.168.1.12 icmp_seq=10 Destination Host Unreachable

###为主机vdbsrv1添加VIP [root@vdbsrv4 ~]# ssh vdbsrv1 "/sbin/ifconfig eth0:0 192.168.1.13 netmask 255.255.255.0 up"

###校验VIP是否成功启用 [root@vdbsrv4 ~]# ping 192.168.1.13 PING 192.168.1.13 (192.168.1.13) 56(84) bytes of data. 64 bytes from 192.168.1.13: icmp_seq=1 ttl=64 time=1.82 ms

###开启MHA [root@vdbsrv4 ~]# masterha_manager --conf=/etc/masterha/app1.cnf &

###模拟主库宕机 [root@vdbsrv4 ~]# ssh vdbsrv1 "killall -r mysqld"

###查看管理节点日志，可以看到VIP已经漂移 [root@vdbsrv4 ~]# grep VIP /var/log/masterha/app1/manager.log Disabling the VIP on old master: vdbsrv1 Enabling the VIP - 192.168.1.13/24 on the new master - vdbsrv2

###验证VIP是否位于节点vdbsrv2 [root@vdbsrv4 ~]# ssh vdbsrv2 "ifconfig |grep 1.13 -B1" eth0:0    Link encap:Ethernet  HWaddr 00:0C:29:5F:B2:EB            inet addr:192.168.1.13  Bcast:192.168.1.255  Mask:255.255.255.0

######查看管理节点MHA切换日志 [root@vdbsrv4 ~]# tail /var/log/masterha/app1/manager.log Invalidated master IP address on vdbsrv1(192.168.1.6:3306) The latest slave vdbsrv2(192.168.1.7:3306) has all relay logs for recovery. Selected vdbsrv2(192.168.1.7:3306) as a new master. vdbsrv2(192.168.1.7:3306): OK: Applying all logs succeeded. vdbsrv2(192.168.1.7:3306): OK: Activated master IP address. vdbsrv3(192.168.1.8:3306): This host has the latest relay log events. Generating relay diff files from the latest slave succeeded. vdbsrv3(192.168.1.8:3306): OK: Applying all logs succeeded. Slave started, replicating from vdbsrv2(192.168.1.7:3306) vdbsrv2(192.168.1.7:3306): Resetting slave info succeeded. Master failover to vdbsrv2(192.168.1.7:3306) completed successfully.

3、VIP切换perl脚本

[root@vdbsrv4 app1]# more /tmp/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
);

my $vip = '192.168.1.13/24';
my $key = '0';
my $ssh_start_vip = "/sbin/ifconfig eth0:$key $vip";
my $ssh_stop_vip = "/sbin/ifconfig eth0:$key down";

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";
}