Nginx+keepalived实现七层的负载均衡

Nginx通过Upstream模块实现负载均衡

upstream 支持的负载均衡算法

主机清单：

主机名	ip	系统	用途
proxy-master	10.36.192.215	centos7.9	主负载
proxy-slave	10.36.192.228	centos7.9	主备
server1	10.36.192.244	Centos7.9	web1
server2	10.36.192.224	centos7.9	Web2
Vip for proxy	10.36.192.99

给所有服务器改成上述对应名称

所有服务都安装nginx并启动

配置nginx的负载均衡

主负载和主备服务器都进入nginx配置文件添加

[root@proxy-master ~]# vim /etc/nginx/conf.d/default.conf

upstream web{
  server 10.36.192.244:80 weight=1 max_fails=3 fail_timeout=20s;
  server 10.36.192.224:80 weight=1 max_fails=3 fail_timeout=20s;
}
server {
  listen 80;
  server_name localhost;
  location / {
    proxy_pass http://web;
    proxy_set_header Host $host:$proxy_port;
    proxy_set_header X-Forwarded-For $remote_addr;
    }
}

[root@proxy-master ~]# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

[root@proxy-master ~]# systemctl restart nginx

在web1和web2服务器网站目录输入不同信息查看

进入web1服务器

[root@server1 ~]# echo “server1” > /usr/share/nginx/html/index.html

进入web2服务器

[root@server2 ~]# echo “server2” > /usr/share/nginx/html/index.html

Keepalived实现调度器HA

注：主/备调度器均能够实现正常调度

1. 主/备调度器安装软件

主负载

[root@proxy-master ~]# yum install -y keepalived

[root@proxy-master ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak

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

! Configuration File for keepalived

global_defs {
   router_id directory1
}

vrrp_instance VI_1 {
    state MASTER         #定义主负载还是主备
    interface ens33      
    virtual_router_id 80
    priority 100         #优先级设置
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1234
    }
    virtual_ipaddress {
        10.36.192.99/24    #vip
    }
}

主备

[root@proxy-slave ~]# yum install -y keepalived

[root@proxy-slave ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak

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

! Configuration File for keepalived

global_defs {
   router_id directory2
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 80
    priority 50
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1234
    }
    virtual_ipaddress {
        10.36.192.99/24
    }
}

启动KeepAlived（主备均启动）

[root@proxy-master ~]# systemctl start keepalived
[root@proxy-master ~]# systemctl enable keepalived
Created symlink from /etc/systemd/system/multi-user.target.wants/keepalived.service to /usr/lib/systemd/system/keepalived.service.

[root@proxy-slave ~]# systemctl start keepalived
[root@proxy-slave ~]# systemctl enable keepalived
Created symlink from /etc/systemd/system/multi-user.target.wants/keepalived.service to /usr/lib/systemd/system/keepalived.service.

到此：
可以解决心跳故障keepalived
不能解决Nginx服务故障

扩展对调度器Nginx健康检查（可选）两台都设置

让Keepalived以一定时间间隔执行一个外部脚本，脚本的功能是当Nginx失败，则关闭本机的Keepalived

[root@proxy-master ~]# vim /etc/keepalived/check-nginx-status.sh

#!/bin/bash												        
/usr/bin/curl -I http://localhost &>/dev/null	
if [ $? -ne 0 ];then										    
#	/etc/init.d/keepalived stop
	systemctl stop keepalived
fi				

[root@proxy-master ~]# chmod a+x /etc/keepalived/check-nginx-status.sh

keepalived使用script

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

! Configuration File for keepalived

global_defs {
   router_id directory1
}
vrrp_script check_nginx {
   script "/etc/keepalived/check-nginx-status.sh"
   interval 5
}
vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 80
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1234
    }
    virtual_ipaddress {
        10.36.192.99/24
    }
    track_script {
        check_nginx
    }
}

如图所示关闭主负载服务器nginx脚本检测到后自动关闭了keepalived转到了主备