MHA VIP切換指令碼

MHA VIP切換指令碼

MHA能夠在10~30秒內實現自動故障檢測和容錯移轉，適用於對高可用性，資料完整性要求較高的場合。要做到無縫切換，還需要依賴於VIP漂移。VIP漂移比較常用的方式為使用keepalived或者使用指令碼直接實現。指令碼方式無須安裝及複雜配置，相對簡單。本文描述了基於指令碼實現VIP切換。

對於keepalived的相關配置可以參考：CentOS 5.9下安裝配置Keepalived   

1、當前主機環境及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環境
[root@vdbsrv4 ~]# more /etc/issue
CentOS release 5.9 (Final)
Kernel \r on an \m

 

###mysql環境
[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配置資訊
[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、測試VIP切換
###測試VIP(192.168.1.13)是否被啟用
[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

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

###校正VIP是否成功啟用
[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

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

###類比主庫宕機
[root@vdbsrv4 ~]# ssh vdbsrv1 "killall -r mysqld"

###查看管理節點日誌，可以看到VIP已經漂移
[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

###驗證VIP是否位於節點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

######查看管理節點MHA切換日誌
[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切換perl指令碼

[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";
}

 

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