centos7下 Mysql+Keepalived 双主热备高可用图文配置详解

环境描述：

Centos7 版本

Master1：192.168.1.146        安装mysql和keepalived

Master2: 192.168.1.147        安装mysql和keepalived

VIP：192.168.1.188

要实现主主同步，可以先实现主从同步，即master1->master2的主从同步，然后master2->master1的主从同步.

这样，双方就完成了主主同步。

注意下面几点：

1）要保证同步服务期间之间的网络联通。即能相互 ping 通，能使用对方授权信息连接到对方数据库（防火墙开放3306端口）。

2）关闭selinux。

3）同步前，双方数据库中需要同步的数据要保持一致。这样，同步环境实现后，再次更新的数据就会如期同步了。

这里略过。

配置Mysql+Keepalived故障转移的高可用环境  

1）安装keepalived并将其配置成系统服务。master1和master2两台机器上同样进行如下操作：

[root@master1 ~] # yum install -y openssl-devel popt-devel

[root@master1 ~] # cd /usr/local/src/

[root@master1 src] # wget http://www.keepalived.org/software/keepalived-1.3.5.tar.gz

[root@master1 src] # tar -zvxf keepalived-1.3.5.tar.gz

[root@master1 src] # cd keepalived-1.3.5

[root@master1 keepalived-1.3.5] # ./configure --prefix=/usr/local/keepalived

[root@master1 keepalived-1.3.5] # make && make install

[root@master1 keepalived-1.3.5] # cp /usr/local/src/keepalived-1.3.5/keepalived/etc/init.d/keepalived /etc/rc.d/init.d/

[root@master1 keepalived-1.3.5] # cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/

[root@master1 keepalived-1.3.5] # mkdir /etc/keepalived/

[root@master1 keepalived-1.3.5] # cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

[root@master1 keepalived-1.3.5] # cp /usr/local/keepalived/sbin/keepalived /usr/sbin/

[root@master1 keepalived-1.3.5] # echo "/etc/init.d/keepalived start" >> /etc/rc.local

2）master1机器上的keepalived.conf配置。（下面配置中没有使用lvs的负载均衡功能，所以不需要配置虚拟服务器virtual server）

[root@master1 ~] # cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak

[root@master1 ~] # vim /etc/keepalived/keepalived.conf       ＃清空默认内容，直接采用下面配置：

! Configuration File for keepalived
       
global_defs {
router_id MASTER-HA
}
       
vrrp_script chk_mysql_port {
    script "/etc/keepalived/chk_mysql.sh"
    interval 2            
    weight -5                 
    fall 2                 
    rise 1               
}
       
vrrp_instance VI_1 {
    state MASTER
    interface ens33    
    mcast_src_ip 192.168.1.146
    virtual_router_id 51    
    priority 101          
    advert_int 1         
    authentication {   
        auth_type PASS 
        auth_pass 1111     
    }
    virtual_ipaddress {    
        192.168.1.188
    }
      
track_script {               
   chk_mysql_port             
}
virtual_server 192.168.1.188 3306 {
    delay_loop 6               
    lb_algo wrr             
    lb_kind DR                 
    #nat_mask 255.255.255.0
    persistence_timeout 50     
    protocol TCP              
    
    ## Real Server设置，3306就是连接端口
    real_server 192.168.1.146 3306 {
        weight 3  ##权重
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
        }
    }
    real_server 192.168.1.147 3306 {
        weight 3
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
        }
    }
}
}

master2机器上的keepalived配置。master2机器上的keepalived.conf文件只修改priority为90、nopreempt不设置、real_server设置本地IP。

! Configuration File for keepalived
       
global_defs {
router_id BACKUP-HA
}
       
vrrp_script chk_mysql_port {
    script "/etc/keepalived/chk_mysql.sh"
    interval 2            
    weight -5                 
    fall 2                 
    rise 1               
}
       
vrrp_instance VI_1 {
    state BACKUP
    interface ens33    
    mcast_src_ip 192.168.1.147
    virtual_router_id 51    
    priority 99          
    advert_int 1         
    authentication {   
        auth_type PASS 
        auth_pass 1111     
    }
    virtual_ipaddress {    
        192.168.1.188
    }
      
track_script {               
   chk_mysql_port             
}
virtual_server 192.168.1.188 3306 {
    delay_loop 6               #服务轮询的时间间隔
    lb_algo wrr                #加权轮询调度，LVS调度算法 rr|wrr|lc|wlc|lblc|sh|sh
    lb_kind DR                 #LVS集群模式 NAT|DR|TUN，其中DR模式要求负载均衡器网卡必须有一块与物理网卡在同一个网段
    #nat_mask 255.255.255.0
    persistence_timeout 50     #会话保持时间
    protocol TCP              #健康检查协议
    
    ## Real Server设置，3306就是连接端口
    real_server 192.168.1.146 3306 {
        weight 3  ##权重
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
        }
    }
    real_server 192.168.1.147 3306 {
        weight 3
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
        }
    }
}
}

编写切换脚本。KeepAlived做心跳检测，如果Master的MySQL服务挂了(3306端口挂了),那么它就会选择自杀。Slave的KeepAlived通过心跳检测发现这个情况，

就会将VIP的请求接管

[root@master1 ~]# vim /etc/keepalived/chk_mysql.sh

#!/bin/bash

counter=$( netstat   -na| grep   "LISTEN" | grep   "3306" | wc   -l)

if   [ "${counter}"   - eq   0 ]; then

    /etc/init .d /keepalived   stop

fi

[root@master1 ~]# chmod 755 /etc/keepalived/chk_mysql.sh     

启动keepalived服务

[root@master1 ~] # /etc/init.d/keepalived start

正在启动 keepalived：                                      [确定]

在启动的时候有可能启动失败   打开 vim /lib/systemd/system/keepalived.service  在第7行

PIDFile=/usr/local/program/keepalived/var/run/keepalived.pid      ##发现这个目录不存在，无法写入keepalived.pid  

修改成 PIDFile=/var/run/keepalived.pid

执行 systemctl daemon-reload    #重新载入 systemd，扫描新的或有变动的单元  

在运行就Ok了    /etc/init.d/keepalived start

ip addr 可以看到 vip在master上

三、测试

最简单的测试

mysql -h192.168.1.188 -uroot1 -proot1

show databases;

在147服务上看 ip addr 也可以看到vip漂移到了147服务上

/******************/

上面那个脚本简单且粗暴，即脚本一旦监测到Master的mysql服务关闭，就立刻把keepalived服务关闭，不能实现vip转移，也就是当Master数据库恢复的是时候不能再切回来！

下面这个脚本可以实现 当监测到Master的mysql服务关闭后，就会将vip切换到Backup上 当Master的mysql服务恢复后，就会再次将VIP资源切回来

#!/bin/bash

MYSQL= /usr/local/mysql/bin/mysql

MYSQL_HOST=localhost

MYSQL_USER=root

MYSQL_PASSWORD=123456

CHECK_TIME=3

#mysql  is working MYSQL_OK is 1 , mysql down MYSQL_OK is 0

MYSQL_OK=1

function   check_mysql_helth (){

    $MYSQL -h $MYSQL_HOST -u $MYSQL_USER -p${MYSQL_PASSWORD} -e "show status;"   > /dev/null   2>&1

    if   [ $? = 0 ] ; then

    MYSQL_OK=1

    else

    MYSQL_OK=0

    fi

    return   $MYSQL_OK

}

while   [ $CHECK_TIME - ne   0 ]

do

    let   "CHECK_TIME -= 1"

    check_mysql_helth

if   [ $MYSQL_OK = 1 ] ; then

    CHECK_TIME=0

    exit   0

fi

if   [ $MYSQL_OK - eq   0 ] &&  [ $CHECK_TIME - eq   0 ]

then

    pkill keepalived

    exit   1

fi

sleep   1

done