理论+实验·MHA高可用配置及故障切换

理论+实验·MHA高可用配置及故障切换

MHA知识点

• MHA概述
  • 一套优秀的MySQL高可用环境下故障切换和主从复制的软件
  • MySQL故障过程中,MHA能做到0-30秒内自动完成故障切换
• MHA的组成
  • MHA Manager (管理节点)
  • MHA Node (数据节点)
• MHA特点
  • 自动故障切换过程中,MHA试图从宕机的主服务器上保存二进制文件,最大程度的保证数据不丢失
  • 使用半同步复制,可以大大降低数据丢失的风险
  • 目前MHA支持一主多从架构,最少三台服务,即一主两从

实验环境

服务器 CentOS 7 mha-manager/20.0.0.17 管理节点,安装manager组件

服务器 CentOS 7 master/20.0.0.20 Master节点,安装node组件

服务器 CentOS 7 slave-master/20.0.0.19 Slave/Master节点,安装node组件

服务器 CentOS 7 slave/20.0.0.18 Slave节点,安装node组件

操作系统版本 CentOS 7版本,MHA版本 0.57 版本.

在三台MySQL节点上分别安装数据库,MySQL版本使用,5.6.36,cmake版本请使用2.8.6.

一、安装MySQL数据库

master、slave-master、slave三台设备上安装MySQL数据库

安装编译依赖的环境

//安装依赖环境//
yum -y install ncurses-devel gcc-c++ perl-Module-Install

安装gmake编译软件

//将源码包放到家目录下//
tar zxvf cmake-2.8.6.tar.gz
cd cmake-2.8.6
./configure
gmake&&gmake install

安装MySQL数据库

//回到家目录//
cd
tar zxvf mysql-5.6.36.tar.gz
cd mysql-5.6.36
cmake \
-DCMAKE_INSTALL_PREFIX=/usr/local/mysql \
-DDEFAULT_CHARSET=utf8 \
-DDEFAULT_COLLATION=utf8_general_ci \
-DWITH_EXTRA_CHARSETS=all \
-DSYSCONFDIR=/etc
make&&make install
cp support-files/my-default.cnf /etc/my.cnf
cp support-files/mysql.server /etc/rc.d/init.d/mysqld
chmod +x /etc/rc.d/init.d/mysqld
chkconfig --add mysqld
echo "PATH=$PATH:/usr/local/mysql/bin" >>/etc/profile
source /etc/profile
groupadd mysql
useradd -M -s /sbin/nologin mysql -g mysql
chown -R mysql.mysql /usr/local/mysql
mkdir -p /data/mysql
//初始化数据库//
/usr/local/mysql/scripts/mysql_install_db \
--basedir=/usr/local/mysql \
--datadir=/usr/local/mysql/data \
--user=mysql

二、配置MySQL一主两从

修改master的著配置文件/etc/mycnf文件,三台服务器的server-id不能相同

• 配置master服务器

vim /etc/my.cnf
...
server-id = 20			//master写20;slave-master写19;slave写18//		
log-bin=master-bin		//开启二进制日志文件//
log-slave-updates=true

• 配置slave-master|slave服务器

vim /etc/my.cnf
...
server-id = 19|18
log_bin=master-bin
relay-log=relay-log-bin
relay-log-index=slave-relay-bin.index

systemctl restart mysqld

三台服务器分别做两个软链接

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

启动MySQL

/usr/local/mysql/bin/mysqld_safe --user=mysql &

配置MySQL、一主两从

• MySQL主从配置相对比较简单.需要注意的是授权.步骤如下
• 在所有数据库节点上授权两个用户,一个是从库同步使用,另外一个是manager使用.

grant replication slave on *.* to 'myslave'@'20.0.0.%' identified by '123';
grant all privileges on *.* to 'mha'@'20.0.0.%' identified by 'manager';
flush privileges;

• 下面三条授权按理论是不用添加的,但是做案例实验环境时候是通过MHA检查MySQL主从有报错,报两个从库通过主机名连接不上主库,所以所有数据库加上下面的授权

grant all privileges on *.* to 'mha'@'master' identified by 'manager';
grant all privileges on *.* to 'mha'@'slave-master' identified by 'manager';
grant all privileges on *.* to 'mha'@'slave' identified by 'manager';
flush privileges;

• 在master主机上查看二进制文件和同步点

show master status;

• 接下来在slave-master和slave分别执行同步

change master to master_host='20.0.0.20',master_user='myslave',master_password='123',master_log_file='master-bin.000001',master_log_pos=1289;
start slave;

• 查看I/O和SQL线程都是yes 代表同步是否正常

setenforce 0
systemctl stop firewalld
mysql> show slave status\G;
//必须设置两个从库为只读模式//
mysql> set global read_only=1;
//注意:设置完成直接验证主从复制功能//
mysql> flush privileges;

三、安装MHA软件

所有服务器上都安装MHA依赖的环境,首先安装epel源

yum -y install epel-release --nogpgcheck

yum -y install perl-DBD-MySQL \
perl-Config-Tiny \
perl-Log-Dispatch \
perl-Parallel-ForkManager \
perl-ExtUtils-CBuilder \
perl-ExtUtils-MakeMaker \
perl-CPAN

MHA软件包对于每个操作系统版本不一样,这里CentOS 7 必须选择0.57版本,在<注意:所有服务器>上必须先安装node组件,最后在MHA-manager节点上安装manager组件,因为manager依赖node组件,下面都是在master上操作演示安装node组件

tar zxvf mha4mysql-node-0.57.tar.gz
cd mha4mysql-node-0.57
perl Makefile.PL
make&&make install

在mha-manager上安装manager组件(!注意:一定要先安装node组件才能安装manager组件)

tar zxvf mha4mysql-manager-0.57.tar.gz
cd mha4mysql-manager-0.57
perl Makefile.PL
make&&make install

//mha-manager安装后/usr/local/bin 下面会生成几个工具,主要包括以下几个//
masterha_check_ssh 检查MHA的SSH配置状况
masterha_check_repl 检查MySQL复制状况
masterha_manager 启动manager的脚本
masterha_check_status 检测当前MHA运行状态
masterha_master_monitor 检测master是否宕机
masterha_master_switch 控制故障转移 (自动或手动)
masterha_conf_host 添加或删除配置的server信息
masterha_stop 关闭manager

//node安装后也会在/usr/local/bin下面会生成几个脚本(这些工具通常由 MHA Manager的脚本除法,无需人为操作)主要如下//
save_binary_logs 保存和复制 master 的二进制日志
apply_diff_relay_logs 识别差异的中继日志事件并将其差异的事件应用于其他的slave
filter_mysqlbinlog 去除不必要的ROLLBACK事件(MHA已不再使用这个工具)
purge_relay_logs 清除中继日志 (不会紫塞SQL线程)

四、配置无密码认证

//在mha-manager上配置到所有数据库节点的无密码认证//
ssh-keygen -t rsa	//一直回车无密码
ssh-copy-id 20.0.0.20
ssh-copy-id 20.0.0.19
ssh-copy-id 20.0.0.18
//在master上配置到数据库节点slave-master和slave的无密码认证//
ssh-keygen -t rsa
ssh-copy-id 20.0.0.19
ssh-copy-id 20.0.0.18
//在slave-master上配置到数据库节点master和slave的无密码认证//
ssh-keygen -t rsa
ssh-copy-id 20.0.0.20
ssh-copy-id 20.0.0.18
//在slave上配置到数据库节点slave-master和master的无密码认证//
ssh-keygen -t rsa
ssh-copy-id 20.0.0.20
ssh-copy-id 20.0.0.19

五、配置MySQL-MHA高可用

配置mha

• 在mha-manager节点上复制相关脚本到/usr/local/bin 目录.

cp -ra /root/mha4mysql-manager-0.57/samples/scripts /usr/local/bin
//拷贝后有四个执行文件
ls /usr/local/bin/scripts/
master_ip_failover  master_ip_online_change  power_manager  send_report

• 复制上述的自动切换时VIP管理的脚本到/usr/local/bin 目录,这里使用脚本管理 VIP

cp /usr/local/bin/scripts/master_ip_failover /usr/local/bin

• 修改内容如下:(删除原有内容,直接复制)

vim /usr/local/bin/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
);
####################添加内容部分#########################################
my $vip = '20.0.0.200';
my $brdc = '20.0.0.255';
my $ifdev = 'ens33';
my $key = '1';
my $ssh_start_vip = "/sbin/ifconfig ens33:$key $vip";
my $ssh_stop_vip = "/sbin/ifconfig ens33:$key down";
my $exit_code = 0;
#my $ssh_start_vip = "/usr/sbin/ip addr add $vip/24 brd $brdc dev $ifdev label $ifdev:$key;/usr/sbin/arping -q -A -c 1 -I $ifdev $vip;iptables -F;";
#my $ssh_stop_vip = "/usr/sbin/ip addr del $vip/24 dev $ifdev label $ifdev:$key";
#######################################################################
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 \"`;
}
# 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";
}

• 创建mha软件目录并拷贝配置文件

mkdir /etc/masterha
cp /root/mha4mysql-manager-0.57/samples/conf/app1.cnf /etc/masterha
vim /etc/masterha/app1.cnf
[server default]
manager_log=/var/log/masterha/app1/manager.log
manager_workdir=/var/log/masterha/app1
master_binlog_dir=/usr/local/mysql/data
master_ip_failover_script=/usr/local/bin/master_ip_failover	//查看路径
master_ip_online_change_script=/usr/local/bin/master_ip_online_change
password=manager
ping_interval=1
remote_workdir=/tmp
repl_password=123
repl_user=myslave
secondary_check_script=/usr/local/bin/masterha_secondary_check -s 20.0.0.19 -s 20.0.0.18
shutdown_script=""
ssh_user=root
user=mha

[server1]
hostname=20.0.0.20
port=3306

[server2]
candidate_master=1
check_repl_delay=0
hostname=20.0.0.19
port=3306

[server3]
hostname=20.0.0.18
port=3306

[root@mha-manager scripts]# cp /usr/local/bin/scripts/master_ip_online_change /usr/local/bin/

[root@mha-manager scripts]# cp /usr/local/bin/scripts/send_report /usr/local/

• 测试无密码认证,如果正常最后会输出successfully

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

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

注意

[root@master ~]# /sbin/ifconfig ens33:1 20.0.0.200/24

• 启动MHA

nohup masterha_manager --conf=/etc/masterha/app1.cnf --remove_dead_master_conf --ignore_last_failover < /dev/null >/var/log/masterha/app1/manager.log 2>&1 &

• 查看MHA状态,可以看到当前的master是master节点

masterha_check_status --conf=/etc/masterha/app1.cnf

• 查看MHA日志,也可以看到当前的master是20.0.020

cat /var/log/masterha/app1/manager.log

• 查看master的VIP地址20.0.0.200 是否存在?,这个VIP地址不会因为manager节点停止MHA服务而消失.

[root@master ~]# ifconfig
ens33: flags=4163  mtu 1500
        inet 20.0.0.20  netmask 255.255.255.0  broadcast 20.0.0.255
        inet6 fe80::f3d9:2d42:9596:bfb9  prefixlen 64  scopeid 0x20
        ether 00:0c:29:81:28:de  txqueuelen 1000  (Ethernet)
        RX packets 610896  bytes 855719895 (816.0 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 205699  bytes 16844848 (16.0 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

ens33:1: flags=4163  mtu 1500
        inet 20.0.0.200  netmask 255.255.255.0  broadcast 20.0.0.255
        ether 00:0c:29:81:28:de  txqueuelen 1000  (Ethernet)

六、模拟 master 故障切换

验证

//mha-manager服务器操作//
[root@mha-manager ~]# tailf /var/log/masterha/app1/manager.log

IN SCRIPT TEST====/sbin/ifconfig ens33:1 down==/sbin/ifconfig ens33:1 20.0.0.200===

Checking the Status of the script.. OK 
Sat Aug 29 20:13:33 2020 - [info]  OK.
Sat Aug 29 20:13:33 2020 - [warning] shutdown_script is not defined.
Sat Aug 29 20:13:33 2020 - [info] Set master ping interval 1 seconds.
Sat Aug 29 20:13:33 2020 - [info] Set secondary check script: /usr/local/bin/masterha_secondary_check -s 20.0.0.19 -s 20.0.0.18
Sat Aug 29 20:13:33 2020 - [info] Starting ping health check on 20.0.0.20(20.0.0.20:3306)..
Sat Aug 29 20:13:33 2020 - [info] Ping(SELECT) succeeded, waiting until MySQL doesn't respond..
^[[A^[[B^[[B^[[C^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^C
[root@localhost scripts]# tailf /var/log/masterha/app1/manager.log

IN SCRIPT TEST====/sbin/ifconfig ens33:1 down==/sbin/ifconfig ens33:1 20.0.0.200===

Checking the Status of the script.. OK 
Sat Aug 29 20:13:33 2020 - [info]  OK.
Sat Aug 29 20:13:33 2020 - [warning] shutdown_script is not defined.
Sat Aug 29 20:13:33 2020 - [info] Set master ping interval 1 seconds.
Sat Aug 29 20:13:33 2020 - [info] Set secondary check script: /usr/local/bin/masterha_secondary_check -s 20.0.0.19 -s 20.0.0.18
Sat Aug 29 20:13:33 2020 - [info] Starting ping health check on 20.0.0.20(20.0.0.20:3306)..
Sat Aug 29 20:13:33 2020 - [info] Ping(SELECT) succeeded, waiting until MySQL doesn't respond..
                                                                       //master服务器操作//
[root@master ~]# pkill -9 mysql
                                                                       //slave-master服务器操作//
[root@slave-master ~]# ifconfig

ens33:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 20.0.0.200  netmask 255.0.0.0  broadcast 20.255.255.255
        ether 00:0c:29:55:a0:0c  txqueuelen 1000  (Ethernet)