Keepalived+Nginx高可用集群

剧终

发布于 2020-08-27 00:32:04

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发布于 2020-08-27 00:32:04

文章被收录于专栏：Linux学习日志

实验环境

172.16.0.10 keepalived+Nginx主负载均衡
172.16.0.8 keepalived+Nginx备负载均衡
172.16.0.4 后端服务器WEB节点1(Nginx站点)
172.16.0.5 后端服务器WEB节点2(Nginx站点)

在所有服务器上面进行配置

systemctl stop firewalld        #关闭防火墙
setenforce 0        　　　　　　　　#关闭selinux，临时生效

配置后端web服务器(两台配置一样)

vim /usr/local/nginx/conf/nginx.conf
worker_processes auto;
events {
    worker_connections  1024;
  }
http {
  include mime.types;
  default_type application/octet-stream;
  server {
        listen       80;
        server_name  www.www.www;
        location / {
            root         /usr/local/nginx/html;
            index index.html index.php; 
        }
  }
}

启动Nginx

/usr/local/nginx/sbin/nginx

配置负载均衡服务器(两台配置一样)

vim /usr/local/nginx/conf/nginx.conf
worker_processes auto;
events {
    worker_connections  1024;
  }
http {
  include mime.types;
  default_type application/octet-stream;
  server {
        listen       80;
        server_name  www.www.www;
        location / {
        proxy_pass http://backend;
        proxy_set_header Host $host:$proxy_port;
        proxy_set_header X-Forwarded-For $remote_addr;
        }
      }
  upstream backend {
    server 172.16.0.4:80 weight=1 fail_timeout=10s max_fails=1 ;
    server 172.16.0.5:80 weight=1 fail_timeout=10s max_fails=1 ;
  }
}

启动Nginx

/usr/local/nginx/sbin/nginx

测试

搭建keepalived，在两台负载均衡节点上面安装keepalived

安装keeplived(两台负载均衡节点安装)

yum install keepalived -y

在master和backup编辑keeplived文件

master:
[root@master /]# cp /etc/keepalived/keepalived.conf{,.bak}
[root@master /]# vim /etc/keepalived/keepalived.conf
global_defs {
   router_id directory1   #调度器的名称，备调度器改为directory2（两个名字一定不能一样）
}

vrrp_instance VI_1 {
state MASTER        #定义主还是备，备用的话写backup
interface ens33     #VIP绑定接口
virtual_router_id 80  #整个集群的调度器一致(在同一个集群)
priority 100         #主调度器优先级  备调度器改为50
advert_int 1         #发包
authentication {
    auth_type PASS      #主备节点认证信息
    auth_pass 1111
}
virtual_ipaddress {
    172.16.0.100/24    #VIP  设置为自己网段
}
}

backup:
[root@backup /]# cp /etc/keepalived/keepalived.conf{,.bak}
[root@backup /]# vim /etc/keepalived/keepalived.conf
global_defs {
   router_id directory2   #调度器的名称，备调度器改为directory2（两个名字一定不能一样）
}

vrrp_instance VI_1 {
    state backup        #定义主还是备，备用的话写backup
    interface ens33     #VIP绑定接口
    nopreempt        #设置到backup上面，不抢占资源
    virtual_router_id 80  #整个集群的调度器一致(在同一个集群)
    priority 50
    advert_int 1         #发包
    authentication {
        auth_type PASS      #主备节点认证信息
        auth_pass 1111
    }
    virtual_ipaddress {
        172.16.0.100/24    #VIP  设置为自己网段
    }
}

启动keepalived查看VIP IP绑定成功了没

[root@master /]# systemct start keeplived
[root@backup /]# systemct start keeplived

Nginx检测脚本

如果有突发情况使得nginx服务不能启动，但是我们的keepalived服务是正常，这个时候用户是访问不到的，VIP也不会自动漂移到备用的节点服务器上。所以我们需要写一些代码来判断一下Nginx服务是不是正常，如果不正常的话我们就将Nginx服务重新启动，如果Nginx启动不了就将keepalived服务关掉，然后实现VIP的漂移，这个时候用户就不会出现无法访问的情况了。

vim /etc/keepalived/chk_nginx.sh
#!/bin/sh
# check nginx server status
NGINX=/usr/local/nginx/sbin/nginx
PORT=80
nmap localhost -p $PORT | grep "$PORT/tcp open"
#echo $?
if [ $? -ne 0 ];then
    $NGINX -s stop
    $NGINX
    sleep 2
    nmap localhost -p $PORT | grep "$PORT/tcp open"
    [ $? -ne 0 ] && systemctl stop keepalived
fi

说明：该脚本的意义就是先检测Nginx是否已经开启默认的80端口：如果存在80端口，一切正常；如果不存在80端口，就执行if段中的语句：先关一下Nginx，在启动Nginx，等待3秒，再次检测80端口，如果还不存在，则杀死keepalived，

配置keepalived文件

vim /etc/keepalived/keepalived.conf
global_defs {
   router_id directory1
}
vrrp_script chk_nginx {
    script "/etc/keepalived/chk_nginx.sh"
    interval 3
    weight 2
}
vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 80
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.16.0.100/24
    }
    track_script {　　　　　　　　　　
        chk_nginx
    }
}