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知识剖析:
-
MHA(Master High Availability)目前在MySQL高可用方面是一个相对成熟的解决方案,它由日本DeNA公司youshimaton(现就职于 Facebook公司)开发,是一套优秀的作为MySQL高可用性环境下故障切换和主从提升的高可用软件。
-
在MySQL故障切换过程中,MHA能做到在 0~30秒之内自动完成数据库的故障切换操作,并且在进行故障切换的过程中,MHA能在最大程度上保证数据的一致性,以达到真正意义上的高可用。
-
该软件由两部分组成:MHA Manager(管理节点)和MHA Node(数据节点)。MHA Manager可以单独部署在一台独立的机器上管理多个master-slave集群,也可以部署在一台slave节点上。MHA Node运行在每台MySQL服务器上,MHA Manager会定时探测集群中的master节点,当master出现故障时,它可以自动将最新数据的slave提升为新的master,然后将所有其 他的slave重新指向新的master。整个故障转移过程对应用程序完全透明。
-
目前MHA主要支持一主多从的架构,要搭建MHA,要求一个复制集群中必须最少有三台数据库服务器,一主二从,即一台充当master,一台充当备用master,另外一台充当从库
实验环境:
主机 | IP | 角色 |
---|---|---|
server3 | 172.25.19.3 | master (主) |
server4 | 172.25.19.4 | slave,(备master) |
server5 | 172.25.19.5 | slave |
server6 | 172.25.19.6 | MHA |
一、基于MHA的MySQL高可用架构搭建
- 首先配置好,基于GTID的主从复制(一主两从)
- 编辑配置文件,然后再重启mysqld(server3,server4,server5一样)
注意:此处省略了数据库的安装过程,想看详细搭建过程可看:https://blog.csdn.net/qq_42036824/article/details/87737208
[root@server3 ~]# vim /etc/my.cnf
server_id=3
gtid_mode=ON
enforce_gtid_consistency=ON
log_bin=binlog
log_slave_updates=ON
[root@server3 ~]# systemctl restart mysqld
server4和server5一样
[root@server4 ~]# vim /etc/my.cnf
server_id=4
gtid_mode=ON
enforce_gtid_consistency=ON
log_bin=binlog
log_slave_updates=ON
[root@server4 ~]# systemctl restart mysqld
[root@server5 ~]# vim /etc/my.cnf
server_id=5
gtid_mode=ON
enforce_gtid_consistency=ON
log_bin=binlog
log_slave_updates=ON
[root@server5 ~]# systemctl restart mysqld
- server3(master)
- 创建授权用户,安装插件
mysql> grant replication slave on *.* to hui@'172.25.19.%' identified by 'HUIyange+32';
Query OK, 0 rows affected, 1 warning (0.07 sec)
mysql> install plugin rpl_semi_sync_master soname 'semisync_master.so';
Query OK, 0 rows affected (0.07 sec)
mysql> install plugin rpl_semi_sync_slave soname 'semisync_slave.so';
Query OK, 0 rows affected (0.07 sec)
mysql> set global rpl_semi_sync_master_enabled=1;
Query OK, 0 rows affected (0.00 sec)
mysql> set global rpl_semi_sync_master_timeout=10000000000000;
Query OK, 0 rows affected (0.00 sec)
mysql> show variables like '%rpl%';
+-------------------------------------------+----------------+
| Variable_name | Value |
+-------------------------------------------+----------------+
| rpl_semi_sync_master_enabled | ON |
| rpl_semi_sync_master_timeout | 10000000000000 |
| rpl_semi_sync_master_trace_level | 32 |
| rpl_semi_sync_master_wait_for_slave_count | 1 |
| rpl_semi_sync_master_wait_no_slave | ON |
| rpl_semi_sync_master_wait_point | AFTER_SYNC |
| rpl_semi_sync_slave_enabled | OFF |
| rpl_semi_sync_slave_trace_level | 32 |
| rpl_stop_slave_timeout | 31536000 |
+-------------------------------------------+----------------+
9 rows in set (0.09 sec)
##创建库,表,并插入信息,用于测试主从复制
mysql> create database westos;
Query OK, 1 row affected (0.05 sec)
mysql> use westos;
Database changed
mysql> create table userlist(
-> username varchar(10) not null,
-> password varchar(15) not null);
Query OK, 0 rows affected (0.28 sec)
mysql> insert into userlist values ('user1','123');
Query OK, 1 row affected (0.07 sec)
mysql> insert into userlist values ('user2','123');
Query OK, 1 row affected (0.08 sec)
mysql> insert into userlist values ('user3','123');
Query OK, 1 row affected (0.08 sec)
- server4(slave)
- 设定从设备,并开启从设备,安装相应插件
mysql> change master to master_host='172.25.19.3',master_user='hui',master_password='HUIyange+32',MASTER_AUTO_POSITION=1;
Query OK, 0 rows affected, 2 warnings (0.36 sec)
mysql> install plugin rpl_semi_sync_master soname 'semisync_master.so';
Query OK, 0 rows affected (0.05 sec)
mysql> install plugin rpl_semi_sync_slave soname 'semisync_slave.so';
Query OK, 0 rows affected (0.04 sec)
mysql> set global rpl_semi_sync_slave_enabled=1;
Query OK, 0 rows affected (0.00 sec)
mysql> stop slave io_thread;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> start slave io_thread;
Query OK, 0 rows affected (0.00 sec)
mysql> start slave;
Query OK, 0 rows affected (0.04 sec)
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 172.25.19.3
Master_User: hui
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: binlog.000004
Read_Master_Log_Pos: 194
Relay_Log_File: server4-relay-bin.000004
Relay_Log_Pos: 401
Relay_Master_Log_File: binlog.000004
Slave_IO_Running: Yes ##两个YES表示同步成功
Slave_SQL_Running: Yes
###查看同步成功
mysql> use westos;
Database changed
mysql> select * from userlist;
+----------+----------+
| username | password |
+----------+----------+
| user1 | 123 |
| user2 | 123 |
| user3 | 123 |
+----------+----------+
- server5(slave)同server4的操作
mysql> change master to master_host='172.25.19.3',master_user='hui',master_password='HUIyange+32',MASTER_AUTO_POSITION=1;
Query OK, 0 rows affected, 2 warnings (0.36 sec)
mysql> install plugin rpl_semi_sync_master soname 'semisync_master.so';
Query OK, 0 rows affected (0.05 sec)
mysql> install plugin rpl_semi_sync_slave soname 'semisync_slave.so';
Query OK, 0 rows affected (0.04 sec)
mysql> set global rpl_semi_sync_slave_enabled=1;
Query OK, 0 rows affected (0.00 sec)
mysql> stop slave io_thread;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> start slave io_thread;
Query OK, 0 rows affected (0.00 sec)
mysql> start slave;
Query OK, 0 rows affected (0.04 sec)
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 172.25.19.3
Master_User: hui
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: binlog.000004
Read_Master_Log_Pos: 194
Relay_Log_File: server4-relay-bin.000004
Relay_Log_Pos: 401
Relay_Master_Log_File: binlog.000004
Slave_IO_Running: Yes ##两个YES表示同步成功
Slave_SQL_Running: Yes
###查看同步成功
mysql> use westos;
Database changed
mysql> select * from userlist;
+----------+----------+
| username | password |
+----------+----------+
| user1 | 123 |
| user2 | 123 |
| user3 | 123 |
+----------+----------+
- 配置MHA
- 下载安装包
- 需要用到的安装包如下:
mha4mysql-manager-0.58.tar.gz
mha4mysql-manager-0.58-0.el7.centos.noarch.rpm
mha4mysql-node-0.58-0.el7.centos.noarch.rpm
perl-Config-Tiny-2.14-7.el7.noarch.rpm
perl-Email-Date-Format-1.002-15.el7.noarch.rpm
perl-Log-Dispatch-2.41-1.el7.1.noarch.rpm
perl-Mail-Sender-0.8.23-1.el7.noarch.rpm
perl-Mail-Sendmail-0.79-21.el7.noarch.rpm
perl-MIME-Lite-3.030-1.el7.noarch.rpm
perl-MIME-Types-1.38-2.el7.noarch.rpm
perl-Parallel-ForkManager-1.18-2.el7.noarch.rpm
- 安装,并将mha4mysql-node发送到另外三台主机
[root@server6 ~]# yum install -y mha4mysql-manager-0.58-0.el7.centos.noarch.rpm mha4mysql-node-0.58-0.el7.centos.noarch.rpm perl-*
[root@server6 ~]# scp mha4mysql-node-0.58-0.el7.centos.noarch.rpm 172.25.19.3:
[root@server6 ~]# scp mha4mysql-node-0.58-0.el7.centos.noarch.rpm 172.25.19.4:
[root@server6 ~]# scp mha4mysql-node-0.58-0.el7.centos.noarch.rpm 172.25.19.5:
- server3,4,5都安装:
[root@server3 ~]# yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm
[root@server4 ~]# yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm
[root@server5 ~]# yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm
- 生成公钥和私钥发送到server3,4,5上,使之互相之间可以进行免密登录
[root@server6 ~]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
13:ab:dc:2f:ae:8c:1b:09:dc:3a:70:01:25:28:1d:3f root@server6
The key's randomart image is:
+--[ RSA 2048]----+
|+oo. |
|oo.. |
|. . E . |
| . o . o |
|. + . S |
| o o o o . |
| o o o . |
| . + .. |
| o.oo... |
+-----------------+
[root@server6 ~]# ssh-copy-id server3 ##输入yes,密码
[root@server6 ~]# ssh-copy-id server4
[root@server6 ~]# ssh-copy-id server5
##将公钥和私钥都发给三个服务器
[root@server6 ~]# scp -r .ssh/ server3:
known_hosts 100% 1026 1.0KB/s 00:00
id_rsa 100% 1675 1.6KB/s 00:00
id_rsa.pub 100% 394 0.4KB/s 00:00
[root@server6 ~]# scp -r .ssh/ server4:
known_hosts 100% 1026 1.0KB/s 00:00
id_rsa 100% 1675 1.6KB/s 00:00
id_rsa.pub 100% 394 0.4KB/s 00:00
[root@server6 ~]# scp -r .ssh/ server5:
known_hosts 100% 1026 1.0KB/s 00:00
id_rsa 100% 1675 1.6KB/s 00:00
id_rsa.pub
- 编写配置文件
[root@server6 ~]# mkdir -p /etc/masterha
[root@server6 ~]# vim /etc/masterha/app1.cnf
[server default]
manager_workdir=/etc/masterha ##设置manager的工作目录
manager_log=/var/log/masterha.log ##设置manager的日志
master_binlog_dir=/var/lib/mysql ##设置master 保存binlog的位置,以便MHA可以找到master的日志,我这里的也就是mysql的数据目录
user=root ##设置监控用户root
password=HUIyange+32 ##设置root用户的登陆mysql的密码
ping_interval=1 ##设置监控主库,发送ping包的时间间隔,默认是3秒,尝试三次没有回应的时候自动进行railover
remote_workdir=/tmp ##设置远端mysql在发生切换时binlog的保存位置
remote_workdir=/tmp ##设置远端mysql在发生切换时binlog的保存位置
repl_password=HUIyange+32 ##设置复制(slave)用户的密码
repl_user=hui ##设置复制环境中的复制用户名
ssh_user=root //设置ssh的登录用户名
[server3]
hostname=172.25.19.3
port=3306
[server4]
hostname=172.25.19.4
candidate_master=1 ##设置为候选master,如果设置该参数以后,发生主从切换以后将会将此从库提升为主库,即使这个主库不是集群中事件最新的slave
check_repl_delay=0 ##默认情况下如果一个slave落后master 100M的relay logs的话,MHA将不会选择该slave作为一个新的master,因为对于这个slave的恢复需要花费很长时间,通过设置check_repl_delay=0,MHA触发切换在选择一个新的master的时候将会忽略复制延时,这个参数对于设置了candidate_master=1的主机非常有用,因为这个候选主在切换的过程中一定是新的master
[server5]
hostname=172.25.19.5
port=3306
no_master=1 ##设置server5不能成为master
- 查看ssh登陆是否成功
[root@server6 ~]# masterha_check_ssh --conf=/etc/masterha/app1.cnf
Tue Feb 26 14:23:40 2019 - [info] All SSH connection tests passed successfully. ##出现successfully则代表成功
- 在master端添加授权,两个slave端设置只读
- server3:
mysql> grant all on *.* to root@'%' identified by 'HUIyange+32';
- server4和server5:
mysql> set global read_only=1;
- 检查整个复制环境状况(健康检查)
[root@server6 masterha]# masterha_check_repl --conf=/etc/masterha/app1.cnf
测试1:手动同步
- 手动关闭server3(master)
[root@server3 ~]# systemctl stop mysqld
- 将master从server3手动同步到server4上
[root@server6 ~]# masterha_master_switch --master_state=dead --conf=/etc/masterha/app1.cnf --dead_master_ip=172.25.19.3 --dead_master_host=172.25.19.3 --dead_master_port=3306 --new_master_host=172.25.19.4 --new_master_port=3306
- 测试在server4上查看slave状态为空,server5上的master显示是server4,说明手动转换成功
- 然后打开server3的mysqld,在sever3上重新添加master
[root@server3 ~]# systemctl start mysqld
- 查看slave的状态,显示master是server4,切换成功
测试2:两个主备master都开启
- 首先删除/etc/masterha/app1.failover.complete,否则再次转换不能成功
[root@server6 ~]# cd /etc/masterha/
[root@server6 masterha]# ls
app1.cnf app1.failover.complete
[root@server6 masterha]# rm -fr app1.failover.complete
- 手动切换新的master——>server3
[root@server6 masterha]# masterha_master_switch --conf=/etc/masterha/app1.cnf --master_state=alive --new_master_host=172.25.19.3 --new_master_port=3306 --orig_master_is_new_slave --running_updates_limit=10000
- 测试结果显示如下(这次server4不用重新添加master)
- server4上显示master为server3
- server5上显示master为server3
测试3:自动切换
- 自动切换命令如下
[root@server6 masterha]# nohup masterha_manager --conf=/etc/masterha/app1.cnf &> /dev/null & ##进程打入后台
2. 然后手动关掉master(现在是server3)
[root@server3 ~]# systemctl stop mysqld
- 然后会发现master转到了server4上
- server4的slave状态为空
- server5显示master转为server4
- server3需要开启mysqld,然后添加master
需要change,然后打开slave,显示master为server4
[root@server3 ~]# systemctl start mysqld
- 查看slave的状态,显示master是server4,切换成功
二、VIP
- 编辑配置文件
[root@server6 ~]# vim /etc/masterha/app1.cnf
##添加如下两行
master_ip_failover_script=/usr/local/bin/master_ip_failover
master_ip_online_change_script=/usr/local/bin/master_ip_online_change
- 解压安装包
[root@server6 ~]# tar zxf mha4mysql-manager-0.58.tar.gz
- 在 /usr/local/bin添加两个文件,并给两个文件添加执行权限
[root@server6 scripts]# cd /usr/local/bin
[root@server6 bin]# vim master_ip_online_change
[root@server6 bin]# vim master_ip_failover
[root@server6 bin]# chmod +x *
- 两个文件内容如下
[root@server6 bin]# vim 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
);
##主要修改下面三行
my $vip = '172.25.19.100/24';
my $ssh_start_vip = "/sbin/ip addr add $vip dev eth0";
my $ssh_stop_vip = "/sbin/ip addr add $vip dev eth0";
GetOptions(
'command=s' => \$command,
'ssh_user=s' => \$ssh_user,
'orig_master_host=s' => \$orig_master_host,
'orig_master_ip=s' => \$orig_master_ip,
'orig_master_port=i' => \$orig_master_port,
'new_master_host=s' => \$new_master_host,
'new_master_ip=s' => \$new_master_ip,
'new_master_port=i' => \$new_master_port,
);
exit &main();
sub main {
print "\n\nIN SCRIPT TEST====$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";
}
[root@server6 bin]# vim master_ip_online_change
#!/usr/bin/env perl
use strict;
use warnings FATAL =>'all';
use Getopt::Long;
##主要修改下面三行
my $vip = '172.25.19.100/24';
my $ssh_start_vip = "/sbin/ip addr add $vip dev eth0";
my $ssh_stop_vip = "/sbin/ip addr add $vip dev eth0";
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, $new_master_ssh_user,
);
GetOptions(
'command=s' => \$command,
'orig_master_is_new_slave' => \$orig_master_is_new_slave,
'orig_master_host=s' => \$orig_master_host,
'orig_master_ip=s' => \$orig_master_ip,
'orig_master_port=i' => \$orig_master_port,
'orig_master_user=s' => \$orig_master_user,
'orig_master_password=s' => \$orig_master_password,
'orig_master_ssh_user=s' => \$orig_master_ssh_user,
'new_master_host=s' => \$new_master_host,
'new_master_ip=s' => \$new_master_ip,
'new_master_port=i' => \$new_master_port,
'new_master_user=s' => \$new_master_user,
'new_master_password=s' => \$new_master_password,
'new_master_ssh_user=s' => \$new_master_ssh_user,
);
exit &main();
sub main {
#print "\n\nIN SCRIPT TEST====$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 "\n\n\n***************************************************************\n";
print "Disabling the VIP - $vip on old master: $orig_master_host\n";
print "***************************************************************\n\n\n\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 "\n\n\n***************************************************************\n";
print "Enabling the VIP - $vip on new master: $new_master_host \n";
print "***************************************************************\n\n\n\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 $orig_master_ssh_user\@$orig_master_host \" $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 $new_master_ssh_user\@$new_master_host \" $ssh_start_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_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";
}
- 在现在的master上(server4),添加VIP
[root@server4 ~]# ip addr add 172.25.19.100/24 dev eth0
测试1:手动转换
- 手动转化master到server3
[root@server6 bin]# masterha_master_switch --conf=/etc/masterha/app1.cnf --master_state=alive --new_master_host=172.25.19.3 --new_master_port=3306 --orig_master_is_new_slave --running_updates_limit=10000
. 查看VIP漂移到server3上,则server3就是VIP
测试2:自动转换
- 发起自动转换命令
[root@server6 bin]# nohup masterha_manager --conf=/etc/masterha/app1.cnf &> /dev/null &
- 关掉server3(现在的master)
[root@server3 ~]# systemctl stop mysqld
- 查看VIP漂移到server4上
- 我们还可以在物理机远程通过VIP登录到数据库
mysql -h 172.25.19.100 -u root -p
这里我就不做演示了,读者可自行查看