keepalived（三）LVS+Keepalived

港控/mmm° 2022-05-12 06:06 243阅读 0赞

# 实验 #

#### 内容 ####

keepalived+lvs实现后端web服务的负载均衡与高可用

#### 架构图 ####

![这里写图片描述][70]

#### 环境 ####

<table> 
 <thead> 
  <tr> 
   <th>ip</th> 
   <th>系统</th> 
   <th>软件</th> 
   <th>角色</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>192.168.253.128</td> 
   <td>CentOS7</td> 
   <td>keepalived</td> 
   <td>keepalived的MASTER节点</td> 
  </tr> 
  <tr> 
   <td>192.168.253.158</td> 
   <td>CentOS7</td> 
   <td>keepalived</td> 
   <td>keepalived的BACKUP节点</td> 
  </tr> 
  <tr> 
   <td>192.168.253.145</td> 
   <td>CentOS7</td> 
   <td>nginx</td> 
   <td>后端web服务器</td> 
  </tr> 
  <tr> 
   <td>192.168.253.129</td> 
   <td>CentOS6</td> 
   <td>nginx</td> 
   <td>后端web服务器</td> 
  </tr> 
 </tbody> 
</table>

第一步：192.168.253.145端安装nginx

systemctl  stop firewalld 
    setenforce 0
    #wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo如果已经有epel源不需要执行
    yum install nginx  -y  #nginx需要epel源才可以yum安装

第二步：192.168.253.145上创建nginx起始页，启动nginx

echo "192.168.253.145" > /usr/share/nginx/html/index.html
    systemctl  start nginx

curl 192.168.253.145 测试一下  
![这里写图片描述][70 1]

第三步：192.168.253.129上安装nginx

/etc/init.d/iptables  stop
    setenforce 0
    #wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-6.repo 已经有epel源不需要执行
    yum install nginx   -y

第四步：192.168.253.129上创建nginx起始页，启动nginx

echo "192.168.253.129" > /usr/share/nginx/html/index.html
    /etc/init.d/nginx  start nginx

curl 192.168.253.129测试一下  
![这里写图片描述][70 2]

第五步：在192.168.253.129和192.168.253.145创建一个脚本用于修改内核参数，阻止arp通告和响应，以及在本地环回接口创建vip192.168.253.190/32

[root@localhost ~]# cat RS.sh 
    #!/bin/bash
    #
    vip=192.168.253.190  ##vip
    mask='255.255.255.255' ##掩码
    
    case $1 in
    start)
        ##阻止arp通告与响应
        echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore  
        echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore
        echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
        echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
    
        ifconfig lo:0 $vip netmask $mask broadcast $vip up #设置vip
        route add -host $vip dev lo:0  #增加主机路由
        ;;
    stop)
        ifconfig lo:0 down
    
        echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore
        echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce
    
        ;;
    *) 
        echo "Usage $(basename $0) start|stop"
        exit 1
        ;;
    esac

在两台机上都执行

sh RS.sh start #启动脚本

第六步：192.168.253.128端安装keepalived并修改/etc/keepalived/keepalived.conf配置文件

systemctl  stop firewalld 
    setenforce  0
    yum install keepalived -y
    [root@localhost ~]# cat /etc/keepalived/keepalived.conf
    ! Configuration File for keepalived
    global_defs { notification_email { root@localhost }
        notification_email_from keepalived@localhost
        smtp_server 127.0.0.1
        smtp_connect_timeout 30
        router_id 192.168.253.128
    }
    
    vrrp_instance VI_1 { state MASTER interface ens33 virtual_router_id 15 priority 95 advert_int 1 authentication { auth_type PASS auth_pass 1234 }
        virtual_ipaddress { 192.168.253.190/32 dev ens33 }
    }
    virtual_server 192.168.253.190 80 { delay_loop 1 lb_algo rr lb_kind DR persistence_timeout 1 protocol TCP real_server 192.168.253.145 80 { weight 1 HTTP_GET { url { path / status_code 200 }
                nb_get_retry 3
                delay_before_retry 1
                connect_timeout 1
            }
        }
    real_server 192.168.253.129 80  { weight 1 HTTP_GET { url { path / status_code 200 }
                nb_get_retry 3
                delay_before_retry 1
                connect_timeout 1
            }
        }
    }

第七步：192.168.253.158端安装keepalived并修改/etc/keepalived/keepalived.conf配置文件

systemctl  stop firewalld 
    setenforce  0
    yum install keepalived -y
    
    [root@localhost ~]# cat /etc/keepalived/keepalived.conf 
    ! Configuration File for keepalived
    global_defs { notification_email { root@localhost }
        notification_email_from keepalived@localhost
        smtp_server 127.0.0.1
        smtp_connect_timeout 30
        router_id 192.168.253.158
    }
    
    vrrp_instance VI_1 { state BACKUP interface ens33 virtual_router_id 15 priority 90 advert_int 1 authentication { auth_type PASS auth_pass 1234 }
        virtual_ipaddress { 192.168.253.190/32 dev ens33 }
    }
    virtual_server 192.168.253.190 80 { delay_loop 1 lb_algo rr lb_kind DR persistence_timeout 1 protocol TCP real_server 192.168.253.145 80 { weight 1 HTTP_GET { url { path / status_code 200 }
                nb_get_retry 3
                delay_before_retry 1
                connect_timeout 1
            }
        }
    real_server 192.168.253.129 80  { weight 1 HTTP_GET { url { path / status_code 200 }
                nb_get_retry 3
                delay_before_retry 1
                connect_timeout 1
            }
        }
    }

第八步：测试  
启动2台keepalived

systemctl start keepalived

![这里写图片描述][70 3]  
可以看到ipvs规则已经产生了。以及vip在192.168.253.128上

然后我们curl一下192.168.253.190  
![这里写图片描述][70 4]

我们使用的调度方法是轮询这里一直是192.168.253.128  
解决方法：将配置文件/etc/keepalived/keepalived.conf的persistence\_timeout 1这一项删掉，这一项是表示持久链接  
然后重启2个keepalived

systemctl restart keepalived

![这里写图片描述][70 5]

lvs测试没问题。这时候试试高可用，我们把192.168.253.128这个主机的keepalived down掉

systemctl stop keepalived

这时候再继续访问192.168.253.190  
![这里写图片描述][70 6]  
同时也可以看到192.168.253.190这个vip飘到192.168.253.158这个BACKUP节点上了。ipvsadm的规则也添加完成。  
![这里写图片描述][70 7]

[70]: /images/20220512/09e0618b56424167bb3925456ab176a7.png
[70 1]: /images/20220512/3a02d012b62744e083ab76a526e4c00e.png
[70 2]: /images/20220512/a3144e73791e44b684433d37bd431520.png
[70 3]: /images/20220512/92866e1d125e41d4bc514999fa3e4a04.png
[70 4]: /images/20220512/2c68f663e0874f4499bb3951a98d7194.png
[70 5]: /images/20220512/a445b047730c4f6bb84cb6ef01971d91.png
[70 6]: /images/20220512/6516fbd829644dc0995bc851898c7bac.png
[70 7]: /images/20220512/a27b300a5cbf41349aaa7d64ef155985.png