keepalive +mysql主从复制实现高可用

安装keepalive

安装依赖插件：

yum install -y gcc openssl-devel popt-devel

wget -q http://www.keepalived.org/software/keepalived-1.2.13.tar.gz
tar -zxvf keepalived-1.2.13.tar.gz
cd keepalived-1.2.13
./configure && make && make install
cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
mkdir /etc/keepalived
cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/
cp /usr/local/sbin/keepalived /usr/sbin/
chkconfig --add keepalived
chkconfig --level 345 keepalived on

在master 主机上的配置

cat /etc/keepalived/keepalived.conf

vrrp_script chk_mysql_port {     #检测mysql服务是否在运行。有很多方式，比如进程，用脚本检测等等
    script "/opt/chk_mysql.sh"   #这里通过脚本监测
    interval 2                   #脚本执行间隔，每2s检测一次
    weight -5                    #脚本结果导致的优先级变更，检测失败（脚本返回非0）则优先级 -5
    fall 2                    #检测连续2次失败才算确定是真失败。会用weight减少优先级（1-255之间）
    rise 1                    #检测1次成功就算成功。但不修改优先级
}
vrrp_instance VI_1 {
    state MASTER
    interface ens33 #指定虚拟ip的网卡接口,不一定是eth0根据ifconfig确定
    virtual_router_id 51 #路由器标识，MASTER和BACKUP必须是一致的
    priority 100 #定义优先级，数字越大，优先级越高，在同一个vrrp_instance下，MASTER的优先级必须大于BACKUP的优先级。这样MASTER故障恢复后，就可以将VIP资源再次抢回来
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 123456
    }
    virtual_ipaddress {
        192.168.11.25
    }
    track_script {
       chk_mysql_port
    }
}

在slave上的配置

cat /etc/keepalived/keepalived.conf

vrrp_script chk_mysql_port {     
    script "/opt/chk_mysql.sh"
    interval 2
    weight -5
    fall 2
    rise 1
}
vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 123456
    }
    virtual_ipaddress {
        192.168.11.25
    }
    track_script {
       chk_mysql_port
    }
}

检测脚本的配置

cat /opt/chk_mysql.sh   

#!/bin/bash
counter=$(netstat -na|grep "LISTEN"|grep "3306"|wc -l)
if [ "${counter}" -eq 0 ]
then
   ## /etc/init.d/keepalived stop
service keepalived stop
else
   echo "running..." >> /opt/keepalived-running-info.log
   sleep 5000
fi

注：

chk_mysql.sh 这个文件要有执行权限 chom -x chk_mysql.sh
要安装netstat 这个命令

# 在master和slave上执行
//sudo /etc/init.d/keepalived start

service keepalived start //keepalived启动

service keepalived stop //keepalive 停止