MYSQL架構中如何主從MHA

這篇文章給大家介紹MYSQL架構中如何主從MHA，內容非常詳細，感興趣的小伙伴們可以參考借鑒，希望對大家能有所幫助。

MHA – GTID模式

MasterHigh Availability Manager and Toolsfor MySQL.是采用PERL語音編寫的一個腳本管理工具，該工具適用于MySQL Replication環境，目的是在與維持master主庫的高可用性。

MHA是自動的master故障轉移和slave提升的軟件包，基于標準的MySQL復制(異步、半同步)

MHA Manager管理節點可以單獨部署在一個獨立服務器上管理多個master-slave集群，也可以部署在一臺slave上。MHA Manager探測集群中的node節點

MHA有兩個組成部分。

MHA Manager (管理節點)

MHA node (數據節點)

下載地址：

https://github.com/yoshinorim/mha4mysql-manager/releases

https://github.com/yoshinorim/mha4mysql-node/releases

MHA Manager管理節點可以單獨部署在一臺服務器上管理多個master-slave集群，也可以部署在一臺slave上，MHA Manager探測集群中的node節點，當發現master出現故障時，它可以自動將具有最新數據的slave提升為新master,然后將所有其他slave導向新的master上。

整個故障轉移過程對應用程序是透明的，MHA node數據節點可以運行在每臺Mysql服務器上，

MHA的目的是維持MYSQL Replication 中master庫的高可用性，其最大特點是可以修復多個slave之間的差異日志，最終使所有slave保持數據一致，然后從中選擇出一個充當新的master,并將其他slave指向它。當master出現故障時，可以通過對比slave之間I/O thread讀取主庫binlog的position號，選取最接近的slave作為備選主庫，其他的從庫可以通過與備選主庫對比生成差異的中繼日志，在備選主庫上應用從原來master保存的binlog,同時將備選主庫提升為master,最后在其他slave上應用相應的差異中繼日志并從新master開始復制。

環境配置

1.安裝Mysql

三個節點安裝mysql

同時，在主節點創建數據庫TEST及TEST數據庫下建立若干表，用于測試目的。

2.建立賬號

三個節點均運行

建立復制賬號

mysql> create user 'rep1'@'192.168.31.%' identified by 'Oracle123';

mysql> grant replication slave on *.* to 'rep1'@'192.168.31.%';

mysql> flush privileges;

建立管理賬號

mysql> create user 'dba'@'192.168.31.%' identified by 'Oracle123';

mysql> grant all privileges on *.* to  'dba'@'192.168.31.%';

mysql> flush privileges;

3.編輯配置文件

主服務器1

[root@mysql ~]# vi /etc/my.cnf

添加內容如下

gtid_mode=on

enforce_gtid_consistency=on

log_bin=on

binlog_format=row

server-id=79

log-bin = master-log

relay-log = relay-log

skip_name_resolve

從服務器1

[root@mysql2 ~]# vi /etc/my.cnf

gtid_mode=on

enforce_gtid_consistency=on

log_slave_updates=1

server-id=188

relay-log = relay-log

log-bin = master-log

skip_name_resolve

relay_log_purge = 0

## read_only = ON  該從庫會被選為候選主庫，故取消read_only

從服務器2

[root@mysql3 ~]# vi /etc/my.cnf

gtid_mode=on

enforce_gtid_consistency=on

log_slave_updates=1

server-id=90

relay-log = relay-log

log-bin = master-log

skip_name_resolve

relay_log_purge = 0

read_only = ON

4.備份還原數據庫

主服務器1

備份TEST數據庫

[root@mysql ~]# mysqldump --single-transaction -uroot -pOracle123 TEST > TEST_20200316.sql

從服務器1

[root@mysql2 ~]# scp root@192.168.31.79:/root/TEST_20200316.sql .

mysql> create database TEST;

[root@mysql2 ~]# mysql -uroot -pOracle123 TEST < TEST_20200316.sql

從服務器2

[root@mysql3 ~]# scp root@192.168.31.79:/root/TEST_20200316.sql .

mysql>  create database TEST;

[root@mysql3 ~]# mysql -uroot -pOracle123 TEST < TEST_20200316.sql

5.重啟數據庫

三個節點都重啟

[root@mysql ~]# service mysql stop

[root@mysql ~]# service mysql start

6.從服務器配置

從服務器兩個節點都執行

[root@mysql2 bin]# mysql -uroot -p

mysql> change master to master_host='192.168.31.79',master_user='rep1',master_password='Oracle123',master_port=3306,master_auto_position=1;

mysql> start slave;

mysql> show slave status\G

注：如果以上執行change master有報錯，Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'The slave is connecting using CHANGE MASTER TO MASTER_AUTO_POSITION = 1, but the master has purged binary logs containing GTIDs that the slave requires.'

解決方式如下：

mysql> change master to master_auto_position=0;

mysql> start slave;

注：如果執行以上出現報錯，

Last_Error: Error 'Table 'test4' already exists' on query. Default database: 'TEST'. Query: 'create table test4 (id integer,name varchar(200))'

解決方式如下:

主庫：mysql> SHOW MASTER STATUS\g  --獲取File Position

從庫執行

mysql> change master to master_host='192.168.31.79',master_user='rep1', master_password='Oracle123',master_port=3306,master_log_file='master-log.000001',master_log_pos=154;

主服務器1

[root@mysql ~]# mysql -uroot -p

mysql> show master status;

7.驗證主從同步

主服務器1

mysql> use TEST;

mysql> insert into test2 values (1,'test1');

mysql> commit;

從服務器1

mysql> use TEST;

mysql> select * from test2;

從服務器2

mysql> use TEST;

mysql> select * from test2;

8.安裝MHA之配置互信

三個節點均執行(包含管理節點)

[root@mysql ~]# cd .ssh/

[root@mysql .ssh]# ssh-keygen -t dsa -P '' -f id_dsa

[root@mysql .ssh]# cat id_dsa.pub >> authorized_keys

主服務器接收秘鑰

主服務器操作

[root@mysql .ssh]# scp 192.168.31.188:/root/.ssh/id_dsa.pub ./id_dsa.pub_188

[root@mysql .ssh]# scp 192.168.31.90:/root/.ssh/id_dsa.pub ./id_dsa.pub_90

[root@mysql .ssh]# cat id_dsa.pub_188 >> authorized_keys

[root@mysql .ssh]# cat id_dsa.pub_90 >> authorized_keys

[root@mysql .ssh]# scp authorized_keys 192.168.31.188:/root/.ssh/

[root@mysql .ssh]# scp authorized_keys 192.168.31.90:/root/.ssh/

三個節點配置host

三個節點均執行

[root@mysql ~]# vi /etc/hosts

添加內如如下:

192.168.31.79 mysql

192.168.31.188     mysql2

192.168.31.90 mysql3

驗證

三個節點均互相測試,不需要輸入密碼即成功

[root@mysql .ssh]# ssh mysql2

[root@mysql .ssh]# ssh mysql3

9.安裝MHA相關rpm

NODE節點安裝

[root@mysql soft]# yum install -y perl-CPAN

[root@mysql soft]# yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm

管理節點安裝(即從服務器1)

如果缺少包，可以下載之后在安裝

https://centos.pkgs.org/

[root@mysql2 ~]# yum install perl-Config-Tiny perl-Email-Date-Format perl-File-Remove perl-Log-Dispatch perl-Mail-Sender perl-Mail-Sendmail perl-MIME-Lite perl-MIME-Types perl-Module-Install perl-Module-ScanDeps perl-Parallel-ForkManager perl-YAML -y

[root@mysql2 soft]# yum install mha4mysql-manager-0.58-0.el7.centos.noarch.rpm

10.配置MHA腳本

每一個節點

[root@mysql ~]# cd /usr/local/

[root@mysql local]# mkdir mha

管理節點(從服務器1)

[root@mysql2 soft]# mkdir /usr/local/mha

[root@mysql2 mha]# vi mha.conf

添加內容如下：

[server default]

user = dba

password = Oracle123

ssh_user = root

repl_user = rep1

repl_password = Oracle123

ping_interval = 1

ping_type = SELECT

manager_workdir=/usr/local/mha

manager_log=/usr/local/mha/manager.log

remote_workdir=/usr/local/mha

master_ip_failover_script="/usr/local/mha/master_ip_failover"

master_ip_online_change_script="/usr/local/mha/master_ip_online_change"

shutdown_script=""

report_script=""

#check_repl_delay=0

[server1]

hostname=mysql

port=3306

master_binlog_dir="/u01/data"

candidate_master=1  ##優先選擇該節點為候選節點

[server2]

hostname=mysql2

port=3306

master_binlog_dir="/u01/data"

candidate_master=1

[server3]

hostname=mysql3

port=3306

master_binlog_dir="/u01/data"

no_master =1   ##不選擇該節點為候選節點

[root@mysql2 mha]# vi master_ip_failover

添加內容如下

#!/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 = '192.168.31.100/32';  # Virtual IP，該ip具體參考步驟12添加IP，顯示出的結果

my $key = "0";

my $int = "enp0s3";

##my $ssh_start_vip = "/sbin/ifconfig $int:$key $vip";  --本環境為centos7，故注釋該指令

##my $ssh_stop_vip = "/sbin/ifconfig $int:$key down"; --本環境為centos7，該指令無效

my $ssh_start_vip = "/sbin/ip addr add $vip dev $int";

my $ssh_stop_vip = "/sbin/ip addr del $vip dev $int";

my $arp_effect = "/sbin/arping -Uq -s192.168.31.100 -I $int 192.168.31.255 -c 3";    # Virtual IP and gatway

#my $test = "echo successfull >/tmp/test.txt";

$ssh_user = "root";

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" ) {

        # $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 \"`;

        &status();

        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 \"`;

    `ssh $ssh_user\@$new_master_host \" $arp_effect \"`;

#    `ssh $ssh_user\@$new_master_host \" $test \"`;

}

# 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 status() {

    print `ssh $ssh_user\@$orig_master_host \" ip add show $int \"`;

}

sub usage {

    print

    "Usage: master_ip_failover --command=start|stop|stopssh|status --orig_master_host=host --orig_maste

r_ip=ip --orig_master_port=port --new_master_host=host --new_master_ip=ip --new_master_port=port\n";

}

[root@mysql2 mha]# vi master_ip_online_change

添加內容如下：

#!/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 $vip = "192.168.31.100/32";

my $if = "enp0s3";

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,

);

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 drop_vip {

        my $output = `ssh -o ConnectTimeout=15  -o ConnectionAttempts=3 $orig_master_host /sbin/ip addr del $vip/32 dev $if`;

}

sub add_vip {

        my $output = `ssh -o ConnectTimeout=15  -o ConnectionAttempts=3 $new_master_host /sbin/ip addr add $vip/32 dev $if`;

}

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";

      print current_time_us() . " drop vip $vip..\n";

      #drop_app_user($orig_master_handler);

     &drop_vip();

      ## 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} );

      }

      ## 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";

      print current_time_us() . "Add vip $vip on $if..\n";

     # create_app_user($new_master_handler);

      &add_vip();

      $new_master_handler->enable_log_bin_local();

      $new_master_handler->disconnect();

      ## Update master ip on the catalog database, etc

      $exit_code = 0;

    };

    if ($@) {

      warn "Got Error: $@\n";

      exit $exit_code;

    }

    exit $exit_code;

  }

  elsif ( $command eq "status" ) {

    # do nothing

    exit 0;

  }

  else {

    &usage();

    exit 1;

  }

}

sub usage {

  print

"Usage: master_ip_online_change --command=start|stop|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";

  die;

}

11.檢查狀態

管理節點

[root@mysql2 mha]# which masterha_check_ssh

[root@mysql2 mha]# chmod +x master_ip_online_change

[root@mysql2 mha]# chmod +x master_ip_failover

[root@mysql2 mha]# masterha_check_ssh --conf=/usr/local/mha/mha.conf

[root@mysql2 mha]# masterha_check_repl --conf=/usr/local/mha/mha.conf

12.在主庫上添加VIP

主服務器1

[root@mysql ~]# ip addr add 192.168.31.100 dev enp0s3

[root@mysql ~]# ip addr show

注意是 100/32

13.啟動MHA

管理節點(即從服務器1)

[root@mysql2 mha]# nohup masterha_manager --conf=/usr/local/mha/mha.conf > /tmp/mha_manager.log < /dev/null 2>&1 &

14.檢驗MHA狀態

管理節點(即從服務器1)

[root@mysql2 mha]# masterha_check_status --conf=/usr/local/mha/mha.conf

15.測試驗證

主服務器1

[root@mysql ~]# service mysql stop

注：

每次出發MHA切換,需要在管理節點刪除mha.failover.complete文件，不然下次切換會報錯。

從服務器1(候選節點)

檢查

[root@mysql2 mha]# tail -100f manager.log

[root@mysql2 mha]# ip addr show

mysql> show slave status\G

mysql> show master status\G

從服務器2

16.后續操作

將原主庫恢復，成為現集群環境的備庫

現主庫操作

mysql> show master status;

原主庫操作

[root@mysql data]# service mysql start

[root@mysql data]# mysql -uroot -p

mysql> change master to master_host='192.168.31.188',master_user='rep1', master_password='Oracle123',master_port=3306,master_log_file='master-log.000001',master_log_pos=409;

mysql> start slave;

mysql> show slave status\G

關于MYSQL架構中如何主從MHA就分享到這里了，希望以上內容可以對大家有一定的幫助，可以學到更多知識。如果覺得文章不錯，可以把它分享出去讓更多的人看到。