MYSQL架构中如何主从MHA
这篇文章给大家介绍MySQL架构中如何主从MHA，内容非常详细，感兴趣的小伙伴们可以参考借鉴，希望对大家能有所帮助。
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MHA – GTID模式
MasterHigh Availability Manager and Toolsfor MySQL.是采用PERL语音编写的一个脚本管理工具，该工具适用于MySQL Replication环境，目的是在与维持master主库的高可用性。
MHA是自动的master故障转移和slave提升的软件包，基于标准的MySQL复制(异步、半同步)
MHA Manager管理节点可以单独部署在一个独立服务器上管理多个master-slave集群，也可以部署在一台slave上。MHA Manager探测集群中的node节点
MHA有两个组成部分。
MHA Manager (管理节点)
MHA node (数据节点)
下载地址：
https://github.com/yoshinorim/mha4mysql-manager/releases
https://github.com/yoshinorim/mha4mysql-node/releases
MHA Manager管理节点可以单独部署在一台服务器上管理多个master-slave集群，也可以部署在一台slave上，MHA Manager探测集群中的node节点，当发现master出现故障时，它可以自动将具有最新数据的slave提升为新master,然后将所有其他slave导向新的master上。
整个故障转移过程对应用程序是透明的，MHA node数据节点可以运行在每台Mysql服务器上，
MHA的目的是维持MYSQL Replication 中master库的高可用性，其最大特点是可以修复多个slave之间的差异日志，最终使所有slave保持数据一致，然后从中选择出一个充当新的master,并将其他slave指向它。当master出现故障时，可以通过对比slave之间I/O thread读取主库binlog的position号，选取最接近的slave作为备选主库，其他的从库可以通过与备选主库对比生成差异的中继日志，在备选主库上应用从原来master保存的binlog,同时将备选主库提升为master,最后在其他slave上应用相应的差异中继日志并从新master开始复制。
环境配置
\ | 主服务器1 | 从服务器1 | 从服务器2 |
OS | Centos el7.x86_64 | Centos el7.x86_64 | Centos el7.x86_64 |
IP | 192.168.31.79 | 192.168.31.188 | 192.168.31.90 |
HOSTNAME | mysql | Mysql2 | Mysql3 |
Mysql-version | 5.7.23 | 5.7.23 | 5.7.23 |
数据库 | TEST | ||
备注1 | vip 192.168.31.100 | ||
备注2 | 管理节点 | ||
备注3 | 候选节点 | ||
备注4 | 单网卡 名：enp0s3 | 单网卡 名：enp0s3 | 单网卡 名：enp0s3 |
1.安装Mysql
三个节点安装mysql
同时，在主节点创建数据库TEST及TEST数据库下建立若干表，用于测试目的。
2.建立账号
三个节点均运行
建立复制账号
mysql> create user 'rep1'@'192.168.31.%' identified by 'Oracle123';
mysql> grant replication slave on *.* to 'rep1'@'192.168.31.%';
mysql> flush privileges;
建立管理账号
mysql> create user 'dba'@'192.168.31.%' identified by 'Oracle123';
mysql> grant all privileges on *.* to 'dba'@'192.168.31.%';
mysql> flush privileges;
3.编辑配置文件
主服务器1
[root@mysql ~]# vi /etc/my.cnf
添加内容如下
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
从服务器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 该从库会被选为候选主库，故取消read_only
从服务器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.备份还原数据库
主服务器1
备份TEST数据库
[root@mysql ~]# mysqldump --single-transaction -uroot -pOracle123 TEST > TEST_20200316.sql
从服务器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
从服务器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.重启数据库
三个节点都重启
[root@mysql ~]# service mysql stop
[root@mysql ~]# service mysql start
6.从服务器配置
从服务器两个节点都执行
[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：如果以上执行change master有报错，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.'
解决方式如下：
mysql> change master to master_auto_position=0;
mysql> start slave;
注：如果执行以上出现报错，
Last_Error: Error 'Table 'test4' already exists' on query. Default database: 'TEST'. Query: 'create table test4 (id integer,name varchar(200))'
解决方式如下:
主库：mysql> SHOW MASTER STATUS\g --获取File Position
从库执行
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;
主服务器1
[root@mysql ~]# mysql -uroot -p
mysql> show master status;
7.验证主从同步
主服务器1
mysql> use TEST;
mysql> insert into test2 values (1,'test1');
mysql> commit;
从服务器1
mysql> use TEST;
mysql> select * from test2;
从服务器2
mysql> use TEST;
mysql> select * from test2;
8.安装MHA之配置互信
三个节点均执行(包含管理节点)
[root@mysql ~]# cd .ssh/
[root@mysql .ssh]# ssh-keygen -t dsa -P '' -f id_dsa
[root@mysql .ssh]# cat id_dsa.pub >> authorized_keys
主服务器接收秘钥
主服务器操作
[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/
三个节点配置host
三个节点均执行
[root@mysql ~]# vi /etc/hosts
添加内如如下:
192.168.31.79 mysql
192.168.31.188 mysql2
192.168.31.90 mysql3
验证
三个节点均互相测试,不需要输入密码即成功
[root@mysql .ssh]# ssh mysql2
[root@mysql .ssh]# ssh mysql3
9.安装MHA相关rpm
NODE节点安装
[root@mysql soft]# yum install -y perl-CPAN
[root@mysql soft]# yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm
管理节点安装(即从服务器1)
如果缺少包，可以下载之后在安装
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脚本
每一个节点
[root@mysql ~]# cd /usr/local/
[root@mysql local]# mkdir mha
管理节点(从服务器1)
[root@mysql2 soft]# mkdir /usr/local/mha
[root@mysql2 mha]# vi mha.conf
添加内容如下：
[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 ##优先选择该节点为候选节点
[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 ##不选择该节点为候选节点
[root@mysql2 mha]# vi master_ip_failover
添加内容如下
#!/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，该ip具体参考步骤12添加IP，显示出的结果
my $key = "0";
my $int = "enp0s3";
##my $ssh_start_vip = "/sbin/ifconfig $int:$key $vip"; --本环境为centos7，故注释该指令
##my $ssh_stop_vip = "/sbin/ifconfig $int:$key down"; --本环境为centos7，该指令无效
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 {
"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
添加内容如下：
#!/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 {
"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.检查状态
管理节点
[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.在主库上添加VIP
主服务器1
[root@mysql ~]# ip addr add 192.168.31.100 dev enp0s3
[root@mysql ~]# ip addr show
注意是 100/32
13.启动MHA
管理节点(即从服务器1)
[root@mysql2 mha]# nohup masterha_manager --conf=/usr/local/mha/mha.conf > /tmp/mha_manager.log < /dev/null 2>&1 &
14.检验MHA状态
管理节点(即从服务器1)
[root@mysql2 mha]# masterha_check_status --conf=/usr/local/mha/mha.conf
15.测试验证
主服务器1
[root@mysql ~]# service mysql stop
注：
每次出发MHA切换,需要在管理节点删除mha.failover.complete文件，不然下次切换会报错。
从服务器1(候选节点)
检查
[root@mysql2 mha]# tail -100f manager.log
[root@mysql2 mha]# ip addr show
mysql> show slave status\G
mysql> show master status\G
从服务器2
16.后续操作
将原主库恢复，成为现集群环境的备库
现主库操作
mysql> show master status;
原主库操作
[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
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