MYSQL MHA搭建-实测

环境：

mysql 5.7.25+MHA(0.58)+redhat6.9

下载及文档

http://code.google.com/p/mysql-master-ha/
分别下载：
mha4mysql-node-0.58
mha4mysql-manger-0.58
版本要选下，主页的版本，编译的时候失败

安装

1.安装node

[root@DEV-ZZZZ] mha4mysql-node-0.58]# perl Makefile.PL
*** Module::AutoInstall version 1.06
*** Checking for Perl dependencies…
[Core Features]

• DBI …loaded. (1.609)
• DBD::mysql …loaded. (4.013)
  *** Module::AutoInstall configuration finished.
  Checking if your kit is complete…
  Looks good
  Writing Makefile for mha4mysql::node

make && make install

2.安装manger

perl Makefile.PL
make && make install

3.配置互信

由于MHA manager通过SSH访问所有的node节点，各个node节点也同样通过SSH来相互发送不同的relay log 文件，所以要在每一个node和manager上配置SSH无密码登陆。
ssh-keygen -t rsa
ssh-copy-id -i ~/.ssh/id_rsa.pub [email protected]
ssh-copy-id -i ~/.ssh/id_rsa.pub [email protected]
ssh-copy-id -i ~/.ssh/id_rsa.pub [email protected]
ssh-copy-id -i ~/.ssh/id_rsa.pub [email protected]
(如果mange和备库再同一个节点，本身给自己也要做)

4.创建mha目录结构

主路径：/usr/local/masterha
cd masterha
mkdir config
mkdir data
mkdir log
mkdir scripts

他可以管理多个mha ，所以最好就是分不同的集群（建议而已，目录结构习惯）

下级目录为dev1 对应的集群名称，里面包含
config —配置文件
data —管理数据
log —日志
scripts —脚本

5.创建配置文件

[server default]
# mysql user and password
user=rep_mha   #MHA管理账户
password=rep_mha
ssh_user=root
repl_user=repl
repl_password=xxx@xxxxx
ssh_user=root
ping_interval=2  #ping间隔时间，用来检查master是否正常
# working directory on the manager
manager_workdir=/usr/local/masterha/dev1/data  #MHA工作目录
# working directory on MySQL servers
remote_workdir=/usr/local/masterha/dev1/data   #MHA工作目录
master_ip_failover_script=/usr/local/masterha/dev1/scripts/master_ip_failover
master_ip_online_change_script=/usr/local/masterha/dev1/scripts/master_ip_online_change
[server1]
hostname=xxx.xxx.xxx.27
master_binlog_dir=/usr/local/mysql/data
#指定MASTER节点binlog存放目录
candidate_master=1
#master宕机后，优先启用这台作为master
[server2]
hostname=xxx.xxx.xxx.28
master_binlog_dir=/usr/local/mysql/data
#指定MASTER节点binlog存放目录
candidate_master=1
#master宕机后，优先启用这台作为master
[server3]
hostname=xxx.xxx.xxx.29
master_binlog_dir=/usr/local/mysql/data
#指定MASTER节点binlog存放目录
no_master=1
#设置na_master=1，使服务器不能成为master

6.创建管理用户

grant all privileges on . to ‘rep_mha’@‘xxx.xxx.xxx.26’ identified by ‘xxx@xxxxx’;
grant all privileges on . to ‘xxx@xxxxx’@‘xxx.xxx.xxx.27’ identified by ‘xxx@xxxxx’;
grant all privileges on . to ‘xxx@xxxxx’@‘xxx.xxx.xxx.28’ identified by ‘xxx@xxxxx’;
grant all privileges on . to ‘xxx@xxxxx’@‘xxx.xxx.xxx.29’ identified by ‘xxx@xxxxx’;
flush privileges;

创建repl用户，在主和备主都需要互相

7.检查

检查ssh互信
masterha_check_ssh --conf=/usr/local/masterha/config/mha.cnf

Tue May 21 17:19:23 2019 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Tue May 21 17:19:23 2019 - [info] Reading application default configuration from /usr/local/masterha/config/mha.cnf..
Tue May 21 17:19:23 2019 - [info] Reading server configuration from /usr/local/masterha/config/mha.cnf..
Tue May 21 17:19:23 2019 - [info] Starting SSH connection tests..
Tue May 21 17:19:24 2019 - [debug] 
Tue May 21 17:19:23 2019 - [debug]  Connecting via SSH from [email protected](xxx.xxx.xxx.27:22) to [email protected](xxx.xxx.xxx.28:22)..
Tue May 21 17:19:23 2019 - [debug]   ok.
Tue May 21 17:19:23 2019 - [debug]  Connecting via SSH from [email protected](xxx.xxx.xxx.27:22) to [email protected](xxx.xxx.xxx.29:22)..
Tue May 21 17:19:24 2019 - [debug]   ok.
Tue May 21 17:19:24 2019 - [debug] 
Tue May 21 17:19:24 2019 - [debug]  Connecting via SSH from [email protected](xxx.xxx.xxx.28:22) to [email protected](xxx.xxx.xxx.27:22)..
Tue May 21 17:19:24 2019 - [debug]   ok.
Tue May 21 17:19:24 2019 - [debug]  Connecting via SSH from [email protected](xxx.xxx.xxx.28:22) to [email protected](xxx.xxx.xxx.29:22)..
Tue May 21 17:19:24 2019 - [debug]   ok.
Tue May 21 17:19:25 2019 - [debug] 
Tue May 21 17:19:24 2019 - [debug]  Connecting via SSH from [email protected](xxx.xxx.xxx.29:22) to [email protected](xxx.xxx.xxx.27:22)..
Tue May 21 17:19:24 2019 - [debug]   ok.
Tue May 21 17:19:25 2019 - [debug]  Connecting via SSH from [email protected](xxx.xxx.xxx.29:22) to [email protected](xxx.xxx.xxx.28:22)..
Tue May 21 17:19:25 2019 - [debug]   ok.
Tue May 21 17:19:25 2019 - [info] All SSH connection tests passed successfully.

检查主从复制是否合适MHA配置
masterha_check_repl --conf=/usr/local/masterha/dev1/config/mha.cnf

Thu May 23 09:05:00 2019 - [info] Checking replication health on xxx.xxx.xxx.28..
Thu May 23 09:05:00 2019 - [info]  ok.
Thu May 23 09:05:00 2019 - [info] Checking replication health on xxx.xxx.xxx.29..
Thu May 23 09:05:00 2019 - [info]  ok.
Thu May 23 09:05:00 2019 - [warning] master_ip_failover_script is not defined.
Thu May 23 09:05:00 2019 - [warning] shutdown_script is not defined.
Thu May 23 09:05:00 2019 - [info] Got exit code 0 (Not master dead).

MySQL Replication Health is OK.

验证成功

其中有有几个问题：

1.注意配置文件项后面是否有空格
会报错如下：

2.socket等版本太老。
可以使用cpan 阿里源 进行更新

cpan
install YAML
install Socket
install IO::Socket::INET6

#打开cpan

cpan
#查看配置>o conf
#指定阿里云cpan源,国内还是这个比较稳定,被墙的你懂的>o conf urllist push http://mirrors.aliyun.com/CPAN/
#提交更改>o conf commit
#查看是否修改成功>o conf urllist
#安装相关插件,记得要按yes>install IO::Socket::INET6
#也是相关插件,记得要按yes>install ExtUtils::Constant
#还是相关插件,记得要按yes>install YAML
#安装上本坑的重点,socket插件>install Socket
#顺便也将坑1的问题也修复一下吧,记得要按yes>install DBD::mysql

出现如下报错

Wed May 22 09:35:31 2019 - [error][/usr/local/share/perl5/MHA/ManagerUtil.pm, ln123] 
"NI_NUMERICHOST" is not exported by the Socket module
 "getaddrinfo" is not exported by the Socket module
 "getnameinfo" is not exported by the Socket module
Can't continue after import errors at /usr/local/share/perl5/MHA/NodeUtil.pm line 29
BEGIN failed--compilation aborted at /usr/local/share/perl5/MHA/NodeUtil.pm line 29.

每台机器上都需要

3.报错：

Wed May 22 11:23:21 2019 - [info]   Connecting to [email protected](xxx.xxx.xxx.28:22).. 
Can't exec "mysqlbinlog": No such file or directory at /usr/local/share/perl5/MHA/BinlogManager.pm line 106.
mysqlbinlog version command failed with rc 1:0, please verify PATH, LD_LIBRARY_PATH, and client options

通过创建软连接

ln -s /usr/local/mysql/bin/mysqlbinlog /usr/local/bin/mysqlbinlog
ln -s /usr/local/mysql/bin/mysql /usr/local/bin/mysql
每台机器都需要

8.启动manger

nohup masterha_manager  --conf=/usr/local/masterha/dev1/config/mha.cnf > /usr/local/masterha/dev1/log/dev1.log 2>&1 &

9.检查mha状态

masterha_check_status --conf=/usr/local/masterha/config/mha.cnf
mha (pid:18426) is running(0:PING_OK), master:xxx.xxx.xxx.27

测试

failover

1.开启一个窗口查询

2.28关闭主mysql

service mysql stop
Shutting down MySQL............                            [  OK  ]

3.执行查询select * from mysql.user;

4.ifconfig查看主机上的ip ，vip已漂移到新的主机27上

5.查看新的主重状态

6.相关日志：

Fri May 24 13:54:58 2019 - [info]     Replicating from xxx.xxx.xxx.28(xxx.xxx.xxx.28:3306)
Fri May 24 13:54:58 2019 - [info]     Not candidate for the new Master (no_master is set)
Fri May 24 13:54:58 2019 - [info] Checking slave configurations..
Fri May 24 13:54:58 2019 - [info]  read_only=1 is not set on slave xxx.xxx.xxx.27(xxx.xxx.xxx.27:3306).
Fri May 24 13:54:58 2019 - [warning]  relay_log_purge=0 is not set on slave xxx.xxx.xxx.27(xxx.xxx.xxx.27:3306).
Fri May 24 13:54:58 2019 - [info]  read_only=1 is not set on slave xxx.xxx.xxx.29(xxx.xxx.xxx.29:3306).
Fri May 24 13:54:58 2019 - [warning]  relay_log_purge=0 is not set on slave xxx.xxx.xxx.29(xxx.xxx.xxx.29:3306).
Fri May 24 13:54:58 2019 - [info] Checking replication filtering settings..
Fri May 24 13:54:58 2019 - [info]  Replication filtering check ok.
Fri May 24 13:54:58 2019 - [info] Master is down!
Fri May 24 13:54:58 2019 - [info] Terminating monitoring script.
Fri May 24 13:54:58 2019 - [info] Got exit code 20 (Master dead).

switchover

1.关闭mha_mange
masterha_stop --conf=/usr/local/masterha/dev1/config/mha.cnf

2.检查状态：
masterha_check_status --conf=/usr/local/masterha/dev1/config/mha.cnf
masterha_check_ssh --conf=/usr/local/masterha/dev1/config/mha.cnf
masterha_check_repl --conf=/usr/local/masterha/dev1/config/mha.cnf

3.切换：
masterha_master_switch --master_state=alive --conf=/usr/local/masterha/config/mha.cnf --new_master_host=xxx.xxx.xxx.28 --orig_master_is_new_slave --running_updates_limit=1000
–orig_master_is_new_slave切换时加上此参数是将原master变为slave节点，如果不加此参数，原来的master将不启动
–running_updates_limit=10000 切换时候选master如果有延迟的话，mha切换不能成功，加上此参数表示延迟在此时间范围内都可切换（单位为s），但是切换的时间长短是由recover时relay日志的大小决定

Mon May 27 21:31:04 2019 - [info] Checking master_ip_failover_script status:
Mon May 27 21:31:04 2019 - [info]   /usr/local/masterha/ste/scripts/master_ip_failover --command=status --ssh_user=root --orig_master_host=192.168.111.78 --orig_master_ip=192.168.111.78 --orig_master_port=3306 
Mon May 27 21:31:04 2019 - [error][/usr/local/share/perl5/MHA/MasterMonitor.pm, ln427] Error happened on checking configurations. Can't exec "/usr/local/masterha/ste/scripts/master_ip_failover": Permission denied at /usr/local/share/perl5/MHA/ManagerUtil.pm line 68.
Mon May 27 21:31:04 2019 - [error][/usr/local/share/perl5/MHA/MasterMonitor.pm, ln525] Error happened on monitoring servers.
Mon May 27 21:31:04 2019 - [info] Got exit code 1 (Not master dead).

MySQL Replication Health is NOT OK!
Mon May 27 21:31:04 2019 - [error][/usr/local/share/perl5/MHA/MasterMonitor.pm, ln229]  Failed to get master_ip_failover_script status with return code 1:0.
Mon May 27 21:31:04 2019 - [error][/usr/local/share/perl5/MHA/MasterMonitor.pm, ln427] Error happened on checking configurations.  at /usr/local/bin/masterha_check_repl line 48.
Mon May 27 21:31:04 2019 - [error][/usr/local/share/perl5/MHA/MasterMonitor.pm, ln525] Error happened on monitoring servers.
Mon May 27 21:31:04 2019 - [info] Got exit code 1 (Not master dead).

chmod u+x 对应的执行文件

附件

对应的脚本

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 = ''xxx.xxx.xxx.xxx';
my $ssh_start_vip = "/sbin/ifconfig eth0:1 $vip";
my $ssh_flush_vip = "arping -c 4 -A -I eth0:1 $vip";
my $ssh_stop_vip = "/sbin/ifconfig eth0:1 down";
GetOptions(
    'command=s'          => \$command,
    'ssh_user=s'         => \$ssh_user,
    'orig_master_host=s' => \$orig_master_host,
    'orig_master_ip=s'   => \$orig_master_ip,
    'orig_master_port=i' => \$orig_master_port,
    'new_master_host=s'  => \$new_master_host,
    'new_master_ip=s'    => \$new_master_ip,
    'new_master_port=i'  => \$new_master_port,
);
exit &main();
sub main {
    print "\n\nIN SCRIPT TEST====$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;
    }
        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 \"`;
    `ssh $ssh_user\@$new_master_host \" $ssh_flush_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";

master_ip_online_change

#!/usr/bin/env perl
use strict;
use warnings FATAL => 'all';

use Getopt::Long;
use MHA::DBHelper;
use MHA::NodeUtil;
use Time::HiRes qw( sleep gettimeofday tv_interval );
use Data::Dumper;

my $_tstart;
my $_running_interval = 0.1;
my (
  $command,
  $orig_master_is_new_slave, $orig_master_host, $orig_master_ip,  $orig_master_port, $orig_master_user,    $orig_master_password, $orig_master_ssh_user,
  $new_master_host,          $new_master_ip,    $new_master_port, $new_master_user,  $new_master_password, $new_master_ssh_user,
);


my $vip = 'xxx.xxx.xxx';
my $ssh_start_vip = "/sbin/ifconfig eth0:1 $vip";
my $ssh_flush_vip = "arping -c 4 -A -I eth0:1 $vip";
my $ssh_stop_vip = "/sbin/ifconfig eth0:1 down";

GetOptions(
  'command=s'                => \$command,
  'orig_master_is_new_slave' => \$orig_master_is_new_slave,
  'orig_master_host=s'       => \$orig_master_host,
  'orig_master_ip=s'         => \$orig_master_ip,
  'orig_master_port=i'       => \$orig_master_port,
  'orig_master_user=s'       => \$orig_master_user,
  'orig_master_password=s'   => \$orig_master_password,
  'orig_master_ssh_user=s'   => \$orig_master_ssh_user,
  'new_master_host=s'        => \$new_master_host,
  'new_master_ip=s'          => \$new_master_ip,
  'new_master_port=i'        => \$new_master_port,
  'new_master_user=s'        => \$new_master_user,
  'new_master_password=s'    => \$new_master_password,
  'new_master_ssh_user=s'    => \$new_master_ssh_user,
);

exit &main();

sub current_time_us {
  my ( $sec, $microsec ) = gettimeofday();
  my $curdate = localtime($sec);
  return $curdate . " " . sprintf( "%06d", $microsec );
}

sub sleep_until {
  my $elapsed = tv_interval($_tstart);
  if ( $_running_interval > $elapsed ) {
    sleep( $_running_interval - $elapsed );
  }
}

sub get_threads_util {
  my $dbh                    = shift;
  my $my_connection_id       = shift;
  my $running_time_threshold = shift;
  my $type                   = shift;
  $running_time_threshold = 0 unless ($running_time_threshold);
  $type                   = 0 unless ($type);
  my @threads;

  my $sth = $dbh->prepare("SHOW PROCESSLIST");
  $sth->execute();
  while ( my $ref = $sth->fetchrow_hashref() ) {
    my $id         = $ref->{Id};
    my $user       = $ref->{User};
    my $host       = $ref->{Host};
    my $command    = $ref->{Command};
    my $state      = $ref->{State};
    my $query_time = $ref->{Time};
    my $info       = $ref->{Info};
    $info =~ s/^\s*(.*?)\s*$/$1/ if defined($info);
    next if ( $my_connection_id == $id );
    next if ( defined($query_time) && $query_time < $running_time_threshold );
    next if ( defined($command)    && $command eq "Binlog Dump" );
    next if ( defined($user)       && $user eq "system user" ); 
    next 
      if ( defined($command)
      && $command eq "Sleep"
      && defined($query_time)
      && $query_time >= 1 );
      
    if ( $type >= 1 ) {
      next if ( defined($command) && $command eq "Sleep" );
      next if ( defined($command) && $command eq "Connect" );
    } 
    
    if ( $type >= 2 ) {
      next if ( defined($info) && $info =~ m/^select/i );
      next if ( defined($info) && $info =~ m/^show/i );
    } 
    
    push @threads, $ref;
  } 
  return @threads;
}

sub main {
  if ( $command eq "stop" ) {
    ## Gracefully killing connections on the current master
    # 1. Set read_only= 1 on the new master
    # 2. DROP USER so that no app user can establish new connections
    # 3. Set read_only= 1 on the current master
    # 4. Kill current queries
    # * Any database access failure will result in script die.
    my $exit_code = 1;
    eval {
      ## Setting read_only=1 on the new master (to avoid accident)
      my $new_master_handler = new MHA::DBHelper();

      # args: hostname, port, user, password, raise_error(die_on_error)_or_not
      $new_master_handler->connect( $new_master_ip, $new_master_port,
        $new_master_user, $new_master_password, 1 );
      print current_time_us() . " Set read_only on the new master.. ";
      $new_master_handler->enable_read_only();
      if ( $new_master_handler->is_read_only() ) {
        print "ok.\n";
      }
      else {
        die "Failed!\n";
      }
      $new_master_handler->disconnect();

      # Connecting to the orig master, die if any database error happens
      my $orig_master_handler = new MHA::DBHelper();
      $orig_master_handler->connect( $orig_master_ip, $orig_master_port,
        $orig_master_user, $orig_master_password, 1 );

      ## Drop application user so that nobody can connect. Disabling per-session binlog beforehand
      #$orig_master_handler->disable_log_bin_local();
      #print current_time_us() . " Drpping app user on the orig master..\n";
      #FIXME_xxx_drop_app_user($orig_master_handler);

      ## Waiting for N * 100 milliseconds so that current connections can exit
      my $time_until_read_only = 15;
      $_tstart = [gettimeofday];
      my @threads = get_threads_util( $orig_master_handler->{dbh},
        $orig_master_handler->{connection_id} );
      while ( $time_until_read_only > 0 && $#threads >= 0 ) {
        if ( $time_until_read_only % 5 == 0 ) {
          printf
"%s Waiting all running %d threads are disconnected.. (max %d milliseconds)\n",
            current_time_us(), $#threads + 1, $time_until_read_only * 100;
          if ( $#threads < 5 ) {
            print Data::Dumper->new( [$_] )->Indent(0)->Terse(1)->Dump . "\n"
              foreach (@threads);
          }
        }
        sleep_until();
        $_tstart = [gettimeofday];
        $time_until_read_only--;
        @threads = get_threads_util( $orig_master_handler->{dbh},
          $orig_master_handler->{connection_id} );
      }

      ## Setting read_only=1 on the current master so that nobody(except SUPER) can write
      print current_time_us() . " Set read_only=1 on the orig master.. ";
      $orig_master_handler->enable_read_only();
      if ( $orig_master_handler->is_read_only() ) {
        print "ok.\n";
      }
      else {
        die "Failed!\n";
      }

      ## Waiting for M * 100 milliseconds so that current update queries can complete
      my $time_until_kill_threads = 5;
      @threads = get_threads_util( $orig_master_handler->{dbh},
        $orig_master_handler->{connection_id} );
      while ( $time_until_kill_threads > 0 && $#threads >= 0 ) {
        if ( $time_until_kill_threads % 5 == 0 ) {
          printf
"%s Waiting all running %d queries are disconnected.. (max %d milliseconds)\n",
            current_time_us(), $#threads + 1, $time_until_kill_threads * 100;
          if ( $#threads < 5 ) {
            print Data::Dumper->new( [$_] )->Indent(0)->Terse(1)->Dump . "\n"
              foreach (@threads);
          }
        }
        sleep_until();
        $_tstart = [gettimeofday];
        $time_until_kill_threads--;
        @threads = get_threads_util( $orig_master_handler->{dbh},
          $orig_master_handler->{connection_id} );
      }



                print "Disabling the VIP on old master: $orig_master_host \n";
                &stop_vip();


      ## Terminating all threads
      print current_time_us() . " Killing all application threads..\n";
      $orig_master_handler->kill_threads(@threads) if ( $#threads >= 0 );
      print current_time_us() . " done.\n";
      #$orig_master_handler->enable_log_bin_local();
      $orig_master_handler->disconnect();

      ## After finishing the script, MHA executes FLUSH TABLES WITH READ LOCK
      $exit_code = 0;
    };
    if ($@) {
      warn "Got Error: $@\n";
      exit $exit_code;
    }
    exit $exit_code;
  }
  elsif ( $command eq "start" ) {
    ## Activating master ip on the new master
    # 1. Create app user with write privileges
    # 2. Moving backup script if needed
    # 3. Register new master's ip to the catalog database

# We don't return error even though activating updatable accounts/ip failed so that we don't interrupt slaves' recovery.
# If exit code is 0 or 10, MHA does not abort
    my $exit_code = 10;
    eval {
      my $new_master_handler = new MHA::DBHelper();

      # args: hostname, port, user, password, raise_error_or_not
      $new_master_handler->connect( $new_master_ip, $new_master_port,
        $new_master_user, $new_master_password, 1 );

      ## Set read_only=0 on the new master
      #$new_master_handler->disable_log_bin_local();
      print current_time_us() . " Set read_only=0 on the new master.\n";
      $new_master_handler->disable_read_only();

      ## Creating an app user on the new master
      #print current_time_us() . " Creating app user on the new master..\n";
      #FIXME_xxx_create_app_user($new_master_handler);
      #$new_master_handler->enable_log_bin_local();
      $new_master_handler->disconnect();

      ## Update master ip on the catalog database, etc
                print "Enabling the VIP - $vip on the new master - $new_master_host \n";
    if ($@) {
      warn "Got Error: $@\n";
      exit $exit_code;
    }
    exit $exit_code;
  }
  elsif ( $command eq "status" ) {

    # do nothing
    exit 0;
  }
  else {
    &usage();
    exit 1;
  }
}

# A simple system call that enable the VIP on the new master 
sub start_vip() {
    `ssh $new_master_ssh_user\@$new_master_host \" $ssh_start_vip \"`;
    `ssh $new_master_ssh_user\@$new_master_host \" $ssh_flush_vip \"`;
}
# A simple system call that disable the VIP on the old_master
sub stop_vip() {
    `ssh $orig_master_ssh_user\@$orig_master_host \" $ssh_stop_vip \"`;
}

sub usage {
  print
"Usage: master_ip_online_change --command=start|stop|status --orig_master_host=host --orig_master_ip=ip --orig_master_port=port --orig_master_user=user --orig_master_password=password --orig_master_ssh_user=sshuser --new_master_host=host --new_master_ip=ip --new_master_port=port --new_master_user=user --new_master_password=password --new_master_ssh_user=sshuser \n";
  die;
}