MHA VIP切换脚本

「爱情、让人受尽委屈。」 2022-08-07 16:47 212阅读 0赞

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][CentOS 5.9_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";
    }

[CentOS 5.9_keepalived]: http://blog.csdn.net/leshami/article/details/42010495