Nginx + Keepalived 负载均衡

更新时间：2022-09-06 17:06:38

喜欢搞Nginx，这两天研究了一下Nginx的负载配置

Nginx平台搭建：Nginx+mysql+php-fpm搭建高性能Nginx平台

熟悉上面的配置之后，今天我再来搞Nginx + Keepalived 的配置，具体拓扑如下：

两台前端Nginx，任意一台挂了另一台会接管岩机Nginx的虚拟Ip，前面还可以做一个DNS轮询，没在线上环境跑过，不知性能如何勒！

一、安装Keepalived

ln -s /usr/src/kernels/2.6.18-194.el5-i686/ /usr/src/linux
tar zxvf keepalived-1.1.15.tar.gz
cd keepalived-1.1.15
./configure --prefix=/usr/local/keepalived
make
make install
cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
mkdir /etc/keepalived
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/ #主配置文件
cp -v /usr/local/keepalived/sbin/keepalived /usr/sbin/
service keepalived start|stop #启动、停止服务

二、配置Keepalived

/etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_script chk_nginx {
        script "/usr/local/keepalived/check_http.sh"
        interval 2
        weight 2
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51   #同一个vrrp_instance，这个ID要相同
    priority 100               #同一个vrrp_instance，这个值master要大于backup
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 123456
    }
        track_script {
                chk_nginx
        }
    virtual_ipaddress {
        192.168.93.144    #定义vip，也就是对外IP，可以写多个（换行）
    }
}

vrrp_instance VI_2 {
    state BACKUP
    interface eth0
    virtual_router_id 52
    priority 50
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 123456
    }
    virtual_ipaddress {
        192.168.93.145
    }
}

global_defs 是全局配置，定义邮件报警，我无视它了。

vrrp_script 定义一个监控脚本，作用：发现Nginx挂了，马上关掉keepalived

vrrp_instance 定义一个虚拟IP，对外服务的，其中还有个track_script ，这个就是调用刚才定义的监控脚本

另外一台前端Nginx的Keepalived配置如下：

! Configuration File for keepalived

vrrp_script chk_nginx {
        script "/usr/local/keepalived/check_http.sh"
        interval 2
        weight 2
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 50
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 123456
    }
    virtual_ipaddress {
        192.168.93.144
    }
}

vrrp_instance VI_2 {
    state MASTER
    interface eth0
    virtual_router_id 52
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 123456
    }
        track_script {
                chk_nginx
        }
    virtual_ipaddress {
        192.168.93.145
    }
}

另外监控脚本check_http.sh可以自己发挥，原则就是发现Nginx挂了就杀掉keepalived就行，写法多种

pid=`ps -C nginx --no-header | wc -l`
if [ $pid -eq 0 ]
then
        /usr/local/nginx/sbin/nginx
        sleep 5
        newpid=`ps -C nginx --no-header | wc -l`
        if [ $newpid -eq 0 ]
        then
                killall keepalived
        fi
fi

Nginx的配置就不多说

启动服务

/usr/local/nginx/sbin/nginx
service keepalived start
ps -aef | grep keepalived
root     28742 3288 0 03:21 pts/1    00:00:00 grep keepalived
root     31674     1 0 Oct31 ?        00:00:00 keepalived -D
root     31676 31674 0 Oct31 ?        00:00:00 keepalived -D
root     31677 31674 0 Oct31 ?        00:00:02 keepalived -D

三、测试

主Nginx

ip add
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:0c:29:e0:a3:bf brd ff:ff:ff:ff:ff:ff
    inet 192.168.93.137/24 brd 192.168.93.255 scope global eth0
    inet 192.168.93.144/32 scope global eth0
    inet6 fe80::20c:29ff:fee0:a3bf/64 scope link
       valid_lft forever preferred_lft forever

备Nginx

ip add
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:0c:29:ee:a6:22 brd ff:ff:ff:ff:ff:ff
    inet 192.168.93.138/24 brd 192.168.93.255 scope global eth0
    inet 192.168.93.145/32 scope global eth0
    inet6 fe80::20c:29ff:feee:a622/64 scope link
       valid_lft forever preferred_lft foreve

我把主Nginx服务停掉之后：

主Nginx

ip add
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:0c:29:e0:a3:bf brd ff:ff:ff:ff:ff:ff
    inet 192.168.93.137/24 brd 192.168.93.255 scope global eth0
    inet6 fe80::20c:29ff:fee0:a3bf/64 scope link
       valid_lft forever preferred_lft forever

备Nginx

ip add
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:0c:29:ee:a6:22 brd ff:ff:ff:ff:ff:ff
    inet 192.168.93.138/24 brd 192.168.93.255 scope global eth0
    inet 192.168.93.145/32 scope global eth0
    inet 192.168.93.144/32 scope global eth0
    inet6 fe80::20c:29ff:feee:a622/64 scope link
       valid_lft forever preferred_lft forever

备机已经接管了主的ip，然后再把主机的服务恢复：

主Nginx

备Nginx

配置完成！

本文转自运维笔记博客51CTO博客，原文链接http://blog.51cto.com/lihuipeng/703123如需转载请自行联系原作者

lihuipeng

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Nginx + Keepalived 负载均衡

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