构建高可用服务器之三 Keepalive冗余Mysql

实验目的：

   通过Keepalive来构建Mysql的高可用。Mysql已做主从，当一台Mysql宕机的时候不影响对Mysql的调用。

实验环境：

  两台Mysql服务器(基于LAMP且已做主从)，两台Mysql服务器都通过Apache发布Discuz论坛(discuz调用的是主mysql地址)。

身份            主机名      IP地址

主Mysql           master      192.168.1.3

从Myslq           slave        192.168.1.4

LAMP平台请参见<<搭建Discuz论坛的两种方式>>

Mysql主从参见<<构建Mysql三部曲之三 主从案例>>

实验步骤：

一、在主mysql上安装配置keepalive

[root@master ~]# bash keepalive_install.sh

“脚本”内容如下：

[root@master ~]# cat keepalive_install.sh
#!/bin/bash
yum -y  install kernel-devel openssl-devel  popt-devel &&
wgethttp://www.keepalived.org/software/keepalived-1.1.15.tar.gz &&
tar -zxf keepalived-1.1.15.tar.gz &&
cd keepalived-1.1.15 &&
./configure--with-kernel-dir=/usr/src/kernels/2.6.32-431.el6.x86_64/ &&
make && make install &&
DIR=/usr/local/
cp $DIR/etc/rc.d/init.d/keepalived  /etc/rc.d/init.d/  &&
cp $DIR/etc/sysconfig/keepalived /etc/sysconfig/&& mkdir -p /etc/keepalived &&
cp $DIR/sbin/keepalived/usr/sbin/&&
cp/usr/local/etc/keepalived/keepalived.conf /etc/keepalived/ &&
/etc/init.d/keepalived restart
if [ $? -eq 0 ];then
        echo -e '\e[32mInstall Keepalive Successfully!\e[0m'
else
        echo -e '\e[31mInstall Keepalive Failure!\e[0m'
fi

加载ip_vs的内核模块

[root@master ~]# modprobe ip_vs
[root@master~]# modprobe ip_vs_wrr
[root@master~]# modprobe ip_vs_rr

修改keepalived.conf配置文件如下：

[root@master ~]# vim /etc/keepalived/keepalived.conf
[root@master ~]# cat/etc/keepalived/keepalived.conf

! Configuration File for keepalived
 
global_defs {
  notification_email {
         [email protected]
   }
  notification_email_from [email protected]
  smtp_server 127.0.0.1
  smtp_connect_timeout 30
  router_id LVS_DEVEL
}
 
vrrp_instance VI_1 {
   state MASTER
   interface eth0
   virtual_router_id 51
   priority 100
   advert_int 1
   authentication {
       auth_type PASS
       auth_pass 1111
    }
   virtual_ipaddress {
         192.168.1.77
    }
}
 
virtual_server 192.168.1.77 3306 {
   delay_loop 6
   lb_algo wrr
   lb_kind DR
   persistence_timeout 50
   protocol TCP
 
   real_server 192.168.1.3 3306 {
       weight 1
         notify_down/data/sh/ keepalive_stop.sh
       TCP_CHECK {
           connect_timeout 3
           nb_get_retry 3
           delay_before_retry 3
             connect_port 3306
       }
    }
}

[root@master ~]# mkdir -p /data/sh
[root@master ~]# vim/data/sh/keepalive_stop.sh
[root@master ~]# chmod +x /data/sh/keepalive_stop.sh
[root@master ~]# /etc/init.d/keepalivedreload
Reloading keepalived:                                      [  OK  ]
[root@master ~]# cat/data/sh/keepalive_stop.sh
#!/bin/bash
/etc/init.d/keepalived stop
[root@master ~]#

二、在从mysql上安装配置keepalive

[root@slave ~]# bash keepalive_install.sh

“脚本”内容如下，同master上执行的脚本一致(非严格意义上的脚本，安装命令放一起而已)。

[root@slave ~]# cat keepalive_install.sh
#!/bin/bash
yum -y install  kernel-developenssl-devel  popt-devel &&
wget http://www.keepalived.org/software/keepalived-1.1.15.tar.gz&&
tar -zxf keepalived-1.1.15.tar.gz &&
cd keepalived-1.1.15 &&
./configure--with-kernel-dir=/usr/src/kernels/2.6.32-431.el6.x86_64/ &&
make && make install &&
DIR=/usr/local/
cp $DIR/etc/rc.d/init.d/keepalived  /etc/rc.d/init.d/  &&
cp $DIR/etc/sysconfig/keepalived/etc/sysconfig/ && mkdir -p /etc/keepalived &&
cp $DIR/sbin/keepalived/usr/sbin/&&
cp/usr/local/etc/keepalived/keepalived.conf /etc/keepalived/ &&
/etc/init.d/keepalived restart
if [ $? -eq 0 ];then
        echo -e '\e[32mInstall Keepalive Successfully!\e[0m'
else
        echo -e '\e[31mInstall Keepalive Failure!\e[0m'
fi
[root@slave ~]#

加载ip_vs的内核模块

[root@master ~]# modprobe ip_vs
[root@master ~]# modprobe ip_vs_wrr
[root@master ~]# modprobe ip_vs_rr

修改keepalived.conf配置文件如下

[root@slave ~]# vim/etc/keepalived/keepalived.conf
[root@slave ~]# cat/etc/keepalived/keepalived.conf

! Configuration File for keepalived
 
global_defs {
  notification_email {
         [email protected]
   }
  notification_email_from [email protected]
  smtp_server 127.0.0.1
  smtp_connect_timeout 30
  router_id LVS_DEVEL
}
 
vrrp_instance VI_1 {
   state BACKUP    !此处同master不一样
   interface eth0
   virtual_router_id 51
   priority 90     !优先级比master上低
   advert_int 1
    authentication{
       auth_type PASS
       auth_pass 1111
    }
   virtual_ipaddress {
         192.168.1.77
    }
}
 
virtual_server 192.168.1.77 3306 {
   delay_loop 6
   lb_algo wrr
   lb_kind DR
   nat_mask 255.255.255.0
   persistence_timeout 50
    protocol TCP
 
   real_server 192.168.1.4 3306 { !Slave上的IP
       weight 1
         notify_down/data/sh/keepalive_stop.sh
       TCP_CHECK {
           connect_timeout 3
           nb_get_retry 3
           delay_before_retry 3
             connect_port 3306
       }
    }
}

[root@slave ~]#
root@slave ~]# mkdir -p /data/sh
[root@slave ~]# vim/data/sh/keepalive_stop.sh
[root@slave ~]# chmod +x/data/sh/keepalive_stop.sh
[root@slave ~]# /etc/init.d/keepalivedreload
Reloading keepalived:                                      [  OK  ]
[root@slave ~]# cat/data/sh/keepalive_stop.sh
#!/bin/bash
/etc/init.d/keepalived stop
[root@slave ~]#

三、修改Discuz论坛数据库连接IP为VIP

直接访问master上的192.168.1.3论坛是可以访问的，且直接访问slave上的192.168.1.4论坛也是可以访问的，现在我们直接访问VIP(虚拟IP) 192.168.1.77依旧可以访问论坛。

这个时候因为discuz调用的是master上的数据库IP，所以我们应该让其调用VIP     192.168.1.77,这样才能保证在主挂的时候自动切换到从上。

在master上

[root@master ~]#sed -i 's/192.168.1.3/192.168.1.77/'/usr/local/apache/htdocs/config/config_global.php
[root@master ~]#/usr/local/apache/bin/apachectl restart

在slave上

[root@slave ~]#sed -i 's/192.168.1.3/192.168.1.77/'/usr/local/apache/htdocs/config/config_global.php
[root@slave ~]#/usr/local/apache/bin/apachectl restart

四、测试

上边两个图很明显可以看出此时VIP在master上。

手动模拟master上的mysql关闭

VIP自动漂到slave上

论坛依旧可以访问