MySQL下高可用故障转移方案MHA的超级部署教程

MHA介绍

MHA是一位日本MySQL大牛用Perl写的一套MySQL故障切换方案，来保证数据库系统的高可用.在宕机的时间内（通常10—30秒内），完成故障切换，部署MHA，可避免主从一致性问题，节约购买新服务器的费用，不影响服务器性能，易安装，不改变现有部署。

还支持在线切换，从当前运行master切换到一个新的master上面，只需要很短的时间（0.5-2秒内），此时仅仅阻塞写操作，并不影响读操作，便于主机硬件维护。

在有高可用，数据一致性要求的系统上，MHA 提供了有用的功能，几乎无间断的满足维护需要。

优点：

1.master自动监控和故障转移

在当前已存在的主从复制环境中，MHA可以监控master主机故障，并且故障自动转移。

即使有一些slave没有接受新的relay log events，MHA也会从最新的slave自动识别差异的relay log events，并apply差异的event到其他slaves。因此所有的slave都是一致的。MHA秒级别故障转移（9-12秒监测到主机故障，任选7秒钟关闭电源主机避免脑裂，接下来apply差异relay logs，注册到新的master，通常需要时间10-30秒即total downtime）。另外，在配置文件里可以配置一个slave优先成为master。因为MHA修复了slave之间的一致性，dba就不用去处理一致性问题。

当迁移新的master之后，并行恢复其他slave。即使有成千上万的slave,也不会影响恢复master时间，slave也很快完成。

DeNA公司在150+主从环境中用MHA。当其中一个master崩溃，MHA4秒完成故障转移，这是主动/被动集群解决方案无法完成的。

2.互动(手动)master故障转移

MHA可以用来只做故障转移，而不监测master，MHA只作为故障转移的交互。

3.非交互式故障转移

非交互式的故障转移也提供（不监控master，自动故障转移）。这个特性很有用，特别是你已经安装了其他软件监控master。比如，用Pacemaker(Heartbeat)监测master故障和vip接管，用MHA故障转移和slave提升。

4.在线切换master到不同主机

在很多情况下，有必要将master转移到其他主机上（如替换raid控制器，提升master机器硬件等等）。这并不是master崩溃，但是计划维护必须去做。计划维护导致downtime，必须尽可能快的恢复。快速的master切换和优雅的阻塞写操作是必需的，MHA提供了这种方式。优雅的master切换， 0.5-2秒内阻塞写操作。在很多情况下0.5-2秒的downtime是可以接受的，并且即使不在计划维护窗口。这意味着当需要更换更快机器，升级高版本时，dba可以很容易采取动作。

5.master crash不会导致主从数据不一致性

当master crash后，MHA自动识别slave间relay logevents的不同，然后应用与不同的slave，最终所有slave都同步。结合通过半同步一起使用，几乎没有任何数据丢失。

其他高可用方案

6.MHA部署不影响当前环境设置

MHA最重要的一个设计理念就是尽可能使用简单。使用与5.0+以上主从环境，其他HA方案需要改变mysql部署设置，MHA不会让dba做这些部署配置，同步和半同步环境都可以用。启动/停止/升级/降级/安装/卸载 MHA都不用改变mysql主从（如启动/停止）。

当你需要升级MHA到新版本时，不需要停止mysql，仅仅更新HMA版本，然后重新启动MHAmanger即可。

MHA 支持包含5.0/5/1/5.5(应该也支持5.6，翻译文档时MHA开发者没更新对于5.6版本)。有些HA方案要求特定的mysql版本（如mysqlcluster，mysql with global transaction id 等）,而且你可能不想仅仅为了MasterHA而迁移应用。很多情况下，公司已经部署了许多传统的mysql应用，开发或dba不想花太多时间迁移到不同的存储引擎或新的特性（newer bleeding edge distributions 不知道这个是否该这么翻译）。

7.不增加服务器费用

MHA 包含MHA Manager和MHA node。MHA node运行在每台mysql服务器上，Manager可以单独部署一台机器，监控100+以上master，总服务器数量不会有太大增加。需要注意的是Manager也可以运行在slaves中的一台机器上。

8.性能无影响

当监控master，MHA只是几秒钟（默认3秒）发送ping包，不发送大的查询。主从复制性能不受影响

9.适用任何存储引擎

Mysql不仅仅适用于事务安全的innodb引擎，在主从中适用的引擎，MHA都可以适用。即使用遗留环境的mysiam引擎，不进行迁移，也可以用MHA。

安装配置方法

1、示例环境介绍

centos 6.4 x64 mysql-5.6.16-linux-glibc2.5-x86_64.tar.gz mha4mysql-manager-0.54.tar.gz mha4mysql-node-0.54.tar.gz

2、服务器说明

masnager 192.168.216.50 master 192.168.216.51 slave 192.168.216.52

三台服务器都安装mysql，将manager作为管理节点

3、配置等价性

manager：

          ssh-keyger -t rsa

          ssh-coyp-id -i /root/.ssh/id_rsa.pub root@192.168.216.50

          ssh-coyp-id -i /root/.ssh/id_rsa.pub root@192.168.216.51

          ssh-coyp-id -i /root/.ssh/id_rsa.pub root@192.168.216.52

          ssh 192.168.216.50 date

          ssh 192.168.216.51 date

          ssh 192.168.216.52 date

master:

          ssh-keyger -t rsa

          ssh-coyp-id -i /root/.ssh/id_rsa.pub root@192.168.216.50

          ssh-coyp-id -i /root/.ssh/id_rsa.pub root@192.168.216.51

          ssh-coyp-id -i /root/.ssh/id_rsa.pub root@192.168.216.52

          ssh 192.168.216.50 date

          ssh 192.168.216.51 date

          ssh 192.168.216.52 date

slave:

          ssh-keyger -t rsa

          ssh-coyp-id -i /root/.ssh/id_rsa.pub root@192.168.216.50

          ssh-coyp-id -i /root/.ssh/id_rsa.pub root@192.168.216.51

          ssh-coyp-id -i /root/.ssh/id_rsa.pub root@192.168.216.52

          ssh 192.168.216.50 date

          ssh 192.168.216.51 date

          ssh 192.168.216.52 date

4、安装mysql

    groupadd mysql

     useradd -g mysql -s /bin/nologin -M mysql

     mkdir -pv /data/mysql

     tar -zxvf mysql-5.6.16-linux-glibc2.5-x86_64.tar.gz
     mv mysql-5.6.16-linux-glibc2.5-x86_64 /usr/local/mysql

     cd /usr/local/mysql/script

     ./ mysql_install_db –user=mysql –basedir=/usr/local/mysql –datadair=/data/mysql

创建mysql配置文件

     vim /usr/local/mysql/my.cnf

    [mysql]

     # CLIENT #

     port              = 3306

     socket             = /tmp/mysql.sock

 

     [mysqld]

     # GENERAL #

     user              = mysql

     default-storage-engine     = InnoDB

     socket             = /tmp/mysql.sock

     pid-file            = /data/mysql/mysql.pid

 

     # MyISAM #

     key-buffer-size        = 32M

     myisam-recover         = FORCE,BACKUP

 

     # SAFETY #

     max-allowed-packet       = 16M

     max-connect-errors       = 1000000

    

     # DATA STORAGE #

     datadir            = /data/mysql/

 

     # BINARY LOGGING #

     server_id                        = 1      #不同服务器不一样

     log-bin            = /data/mysql/mysql-bin

     expire-logs-days        = 14

     sync-binlog          = 1

 

     # CACHES AND LIMITS #

     tmp-table-size         = 32M

     max-heap-table-size      = 32M

     query-cache-type        = 0

     query-cache-size        = 0

     max-connections        = 500

     thread-cache-size       = 50

     open-files-limit        = 65535

     table-definition-cache     = 1024

     table-open-cache        = 2048

 

     # INNODB #

     innodb-flush-method      = O_DIRECT

     innodb-log-files-in-group   = 2

     innodb-log-file-size      = 64M

     innodb-flush-log-at-trx-commit = 1

     innodb-file-per-table     = 1

     innodb-buffer-pool-size    = 592M

 

     # LOGGING #

     log-error           = /data/mysql/mysql-error.log

     log-queries-not-using-indexes = 1

     slow-query-log         = 1

     slow-query-log-file      = /data/mysql/mysql-slow.log

5、配置权限

manager：

          grant all privileges on *.* to root@'127.0.0.1' identified by 'root';

          grant all privileges on *.* to root@'localhost' identified by 'root';

          grant all privileges on *.* to root@'192.168.216.50' identified by 'root';

          grant replication slave on *.* to slave@'192.168.216.50' identified by 'slave';

          grant replication slave on *.* to slave@'192.168.216.51' identified by 'slave';

          grant replication slave on *.* to slave@'192.168.216.52' identified by 'slave';

master:

          grant all privileges on *.* to root@'127.0.0.1' identified by 'root';

          grant all privileges on *.* to root@'localhost' identified by 'root';

          grant all privileges on *.* to root@'192.168.216.50' identified by 'root';

          grant replication slave on *.* to slave@'192.168.216.50' identified by 'slave';

          grant replication slave on *.* to slave@'192.168.216.51' identified by 'slave';

          grant replication slave on *.* to slave@'192.168.216.52' identified by 'slave';

slave:

          grant all privileges on *.* to root@'127.0.0.1' identified by 'root';

          grant all privileges on *.* to root@'localhost' identified by 'root';

          grant all privileges on *.* to root@'192.168.216.50' identified by 'root';

          grant all privileges on *.* to root@'192.168.216.51' identified by 'root';

          grant replication slave on *.* to slave@'192.168.216.50' identified by 'slave';

          grant replication slave on *.* to slave@'192.168.216.51' identified by 'slave';

          grant replication slave on *.* to slave@'192.168.216.52' identified by 'slave';

6、安装依赖包

管理服务器manager需要安装以下全部

perl-Config-Tiny

perl-Params-Validate

perl-Parallel-ForkManager

perl-Log-Dispatch

|- perl-MIME-Lite-3.027-2.el6.noarch.rpm

     |- perl-MIME-Types-1.28-2.el6.noarch.rpm

     |- perl-Email-Date-Format-1.002-5.el6.noarch.rpm

     |- perl-MailTools-2.04-4.el6.noarch.rpm

          |- perl-TimeDate-1.16-11.1.el6.noarch.rpm

          |- perl-Data-ShowTable-3.3-3.4.noarch.rpm

|- perl-Mail-Sender-0.8.22-21.1.noarch.rpm

     |- perl-IO-Socket-SSL-1.31-2.el6.noarch.rpm

          |- perl-Net-LibIDN-0.12-3.el6.x86_64.rpm

          |- perl-Net-SSLeay-1.35-9.el6.x86_64.rpm

     |-perl-Win32API-Registry

|- perl-Mail-Sendmail-0.79_16-4.2.noarch.rpm

     rpm -ivh ncftp-debuginfo-3.2.3-1.3.x86_64.rpm

     rpm -ivh perl-Parallel-ForkManager-0.7.5-2.2.el6.rf.noarch.rpm

     rpm -ivh perl-Params-Validate-0.91-2.4.x86_64.rpm

     rpm -ivh perl-Config-Tiny-2.12-7.1.el6.noarch.rpm

     rpm -ivh perl-MIME-Types-1.28-2.el6.noarch.rpm

     rpm -ivh perl-Email-Date-Format-1.002-5.el6.noarch.rpm

     rpm -ivh perl-TimeDate-1.16-11.1.el6.noarch.rpm

     rpm -ivh perl-Data-ShowTable-3.3-3.4.noarch.rpm

     rpm -ivh perl-MailTools-2.04-4.el6.noarch.rpm

     rpm -ivh perl-MIME-Lite-3.027-2.el6.noarch.rpm

     rpm -ivh perl-Net-LibIDN-0.12-3.el6.x86_64.rpm

     rpm -ivh perl-Net-SSLeay-1.35-9.el6.x86_64.rpm

     rpm -ivh perl-IO-Socket-SSL-1.31-2.el6.noarch.rpm

     rpm -ivh perl-Mail-Sendmail-0.79_16-4.2.noarch.rpm

     rpm -ivh perl-Mail-Sender-0.8.22-21.1.noarch.rpm

     rpm -ivh perl-Log-Dispatch-2.22-7.3.noarch.rpm

如果安perl-DBD-MySQL-4.013-3.el6.x86_64.rpm在检查rep是报错则需要手动编译安装

     tar -zxvf DBD-mysql-4.027.tar.gz

     cd DBD-mysql-4.0.27

     perl Makefile.PL

     make && make install

节点服务器安装

     rpm -ivh ncftp-debuginfo-3.2.3-1.3.x86_64.rpm

     rpm -ivh perl-DBD-MySQL-4.013-3.el6.x86_64.rpm

7、创建软连接

     ln -s /usr/local/mysql/bin/mysqlbinlog /usr/bin/mysqlbinlog

     ln -s /usr/local/mysql/bin/mysql /usr/bin/mysql

导出mysql库搜索路径

     vim /etc/ld.so.conf.d/mysql-x86_64.conf

       /usr/local/mysql/lib

     ldconfig

8、在所有服务器上安装mha4mysql-node-0.54.tar.gz

     tar -zxvf mha4mysql-node-0.54.tar.gz

     cd mha4mysql-node-0.54

     perl Makefile.PL

     make && make install

9、在管理服务上安装 mha4mysql-manager-0.54.tar.gz

     tar -zxvf mha4mysql-manager-0.54.tar.gz

     cd mha4mysql-manager-0.54

     perl Makefile.PL

     make && make install

     mkdir -pv /etc/masterha

     mkdir -pv /masterha/app1

     cp samples/conf/* /etc/masterha

     cp samples/scripts/* /usr/local/bin

     vim /etc/masterha/app1.cnf

     [server default]

     manager_workdir=/masterha/app1

     manager_log=/masterha/app1/manager.log

 

     user=root

     password=root

 

     ssh_user=root

     repl_user=slave

     repl_password=slave

     shutdown_script=""

     #master_ip_failover_script="/usr/local/bin/masterha_ip_failover"

     master_ip_online_change_script="/usr/local/bin/masterha_ip_failover "

     report_script=""

 

     [server1]

     hostname=192.168.216.50

     master_binlog_dir="/data/mysql/"

     candidate_master=1

 

     [server2]

     hostname=192.168.216.51

     master_binlog_dir="/data/mysql/"

     candidate_master=1

 

     [server3]

     hostname=192.168.216.52

     master_binlog_dir="/data/mysql/"

     candidate_master=1

10、测试ssh连接

     masterha_check_ssh –conf=/etc/masterha/app1.cnf

11、测试replication

    masterha_check_repl –conf=/etc/masterha/app1.cnf

12、开启管理节点进程

   masterha_manager –conf=/etc/masterha/app1.cnf

13、测试故障转移

关闭主库mysql，查看从库的的状态是否将同步ip切换到新的主库

14、设置故障转移的ip

     vim /etc/masterha/app1.cnf

          master_ip_failover_script="/usr/local/bin/masterha_ip_failover "

          master_ip_online_change_script="/usr/local/bin/masterha_ip_failover "

编辑故障转移脚本，将vip设置成192.168.216.100

     vim /usr/local/bin/masterha_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 = '172.16.21.119/24'; # Virtual IP

my $vip = '192.168.216.100/24'; # Virtual IP

my $key = "1";

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 "nnIN SCRIPT TEST====$ssh_stop_vip==$ssh_start_vip===nn";

 

  if ( $command eq "stop" || $command eq "stopssh" ) {

 

    # $orig_master_host, $orig_master_ip, $orig_master_port are passed.

    # If you manage master ip address at global catalog database,

    # invalidate orig_master_ip here.

    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" ) {

 

    # all arguments are passed.

    # If you manage master ip address at global catalog database,

    # activate new_master_ip here.

    # You can also grant write access (create user, set read_only=0, etc) here.

    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 master

sub start_vip() {

  `ssh $ssh_user@$new_master_host " $ssh_start_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=portn";

}

测试脚本

/usr/local/bin/masterha_ip_failover –command=status –ssh_user=root –orig_master_host=192.168.216.51 –orig_master_ip=192.168.216.51 –orig_master_port=3306

虚拟ip要手动启动，在主库故障后会自动转移。

/usr/local/bin/masterha_ip_failover –command=start –ssh_user=root –orig_master_host=192.168.216.51 –orig_master_ip=192.168.216.51 –orig_master_port=3306 –new_master_host=192.168.216.51

测试ip故障转移：

关闭主库mysql，查看vip是否转移的新的主库上。