Keeplived配置Nginx双机高可用

一、简介
不管是Keepalived还是Heartbeat做高可用，其高可用，都是站在服务器脚本去说的高可用，而不是服务的角度。
也就是说，如果服务器DOWN机或者网络出现故障，高可用是可以实现自动切换的。如果运行的服务，比如Nginx挂掉
这些高可用软件是意识不到的，需要自己写脚本去实现服务的切换。

二、安装配置Keepalived

# ./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/
# cp /usr/local/sbin/keepalived /usr/bin/
# chkconfig --add keepalived 
# mkdir /etc/keepalived/
# cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/

编辑MASTER的主配置文件(MASTER: 1.1.1.1)

# vim /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
   router_id LVS_DEVEL
}
vrrp_script chk_nginx {
        script "/opt/monnginx.sh"
        interval 2
        weight 2
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass mdnginx
    }
    virtual_ipaddress {
        1.1.1.100
    }
    track_script {
        chk_nginx
  }
}

编辑BACKUP的主配置文件（BACKUP:1.1.1.2）

# vim /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
   router_id LVS_DEVEL
}
vrrp_script chk_nginx {
        script "/opt/monnginx.sh"
        interval 2
        weight 2
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass mdnginx
    }
    virtual_ipaddress {
        1.1.1.100
    }
    track_script {
        chk_nginx
  }
}

三、启动服务与脚本编写（主机和备机都要执行）

# service nginx start
# service keepalived start

编写监控Nginx的脚本

# vim /opt/monnginx.sh
#!/bin/bash
# author: honway.liu
# date: 2013-03-15

if [ $(ps -C nginx --no-header | wc -l) -eq 0 ]; then
        service nginx start
fi
sleep 3
if [ $(ps -C nginx --no-header | wc -l) -eq 0 ]; then
        service keepalived stop
fi

改进脚本，加上报警功能。

# vim /opt/monnginx.sh

#!/bin/bash
# author: honway.liu
# date: 2013-03-15
IPADDR=$(ip addr show eth0|awk '{print $2}' | sed -n 3p)
contact=(137XXXXXXXX@139.com)
num=${#contact[@]}
function email() {
for ((i=0;i<num;i++));do
        echo "$IPADDR service problem" | mail -s "WARNING" ${contact[i]} -- -f gm100861@gmail.com
done
}

if [ $(ps -C nginx --no-header | wc -l) -eq 0 ]; then
        service nginx start
fi
email

sleep 3

if [ $(ps -C nginx --no-header | wc -l) -eq 0 ]; then
        service keepalived stop
email
fi

这里的报警使用的是139邮箱，在139邮箱里面设置有邮件的时候，通知到手机，并且以长短信的方式。
需要开户本机的sendmail服务。

转载请保留固定链接： https://linuxeye.com/configuration/1377.html

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Keeplived配置Nginx双机高可用