# CentOS7 搭建LVS/NAT 负载均衡集群

实验拓扑图：

操作流程：

Director Server pc50 : 192.168.37.50

172.16.131.244
安装并启用ipvsadm
创建虚拟服务器
向虚拟服务器上加入节点

web Server1 pc51: 192.168.37.51

web Server2 pc52: 192.168.37.52
配置WEB 客户端

Clinet : 172.16.131.247
连接虚拟服务器测试

具体步骤：

全局环境准备：

配置yam源或准备以下需要的软件

# systemctl stop firewalld.service //关闭防火墙  
# systemctl disable firewalld.service //关闭开机自启
# firewall-cmd --state //查看                    
# setenforce 0                          //设置SELinux 为宽松模式

web服务器 pc51 / pc52 ：

# yum -y install httpd
[root@pc51 ~]# echo '192.168.37.51' > /var/www/html/test.html
[root@pc52 ~]# echo "192.168.37.52" > /var/www/html/test.html
# systemctl start httpd  
# systemctl enable httpd 
# yum -y install elinks
[root@pc51 ~]# elinks --dump http://localhost/test.html
  192.168.37.51
[root@pc52 ~]# elinks --dump http://localhost/test.html
  192.168.37.52

配置分发器 pc50：

#yum -y install ipvsadm
//开启内核的路由转发功能
# echo "net.ipv4.ip_forward=1" > /etc/sysctl.conf
# sysctl -p
net.ipv4.ip_forward = 1

网站服务器 pc51 / pc52 ：

指定网关地址 192.168.37.50

# route -n//查看路由
# route add default gw 192.168.37.50//临时配置网关 网卡重启后生效
//永久配置网关
# vim /etc/sysconfig/network-scripts/ifcfg-ens33
最后加：GATEWAY=192.168.37.50

# systemctl  restart  network     //重新加载网卡

客户端 172.16.131.247 配置

指定网关地址 172.16.131.244 ：

# vim /etc/sysconfig/network-scripts/ifcfg-ens33

最后加：GATEWAY=172.16.131.244

# systemctl  restart  network
# ping -c 2 192.168.37.51  //测试
PING 192.168.37.51 (192.168.37.51) 56(84) bytes of data.
64 bytes from 192.168.37.51: icmp_seq=1 ttl=63 time=0.322 ms
64 bytes from 192.168.37.51: icmp_seq=2 ttl=63 time=0.503 ms

--- 192.168.37.51 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1000ms
rtt min/avg/max/mdev = 0.322/0.412/0.503/0.092 ms
# yum -y install elinks

配置分发器 pc50 ：

# yum -y install ipvsadm
# rpm -q ipvsadm
ipvsadm-1.27-7.el7.x86_64

添加虚拟服务

        # ipvsadm -L  //查看 IPVS
        IP Virtual Server version 1.2.1 (size=4096)
        Prot LocalAddress:Port Scheduler Flags
          -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
        # ipvsadm -A -t 172.16.131.244:80 -s rr//添加虚拟服务 调度算法为Round Robin
        # ipvsadm -Ln   //- n  数字显示
        IP Virtual Server version 1.2.1 (size=4096)
        Prot LocalAddress:Port Scheduler Flags
          -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
        TCP  172.16.131.244:80 rr
                //向虚拟服务器中加入节点
        # ipvsadm -a -t 172.16.131.244:80 -r 192.168.37.51:80 -m
        # ipvsadm -a -t 172.16.131.244:80 -r 192.168.37.52:80 -m
        # ipvsadm -Ln
        IP Virtual Server version 1.2.1 (size=4096)
        Prot LocalAddress:Port Scheduler Flags
          -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
        TCP  172.16.131.244:80 rr
          -> 192.168.37.51:80              Masq    1      0          0         
          -> 192.168.37.52:80              Masq    1      0          0   

客户端测试

        # elinks --dump http://172.16.131.244/test.html
           192.168.37.51
        # elinks --dump http://172.16.131.244/test.html
           192.168.37.52
        //客户端 轮询到不同的后端真实服务器      

Director Server 查看：

        [root@pc50 ~]# ipvsadm -Ln --stats
        IP Virtual Server version 1.2.1 (size=4096)
        Prot LocalAddress:Port               Conns   InPkts  OutPkts  InBytes OutBytes
          -> RemoteAddress:Port
        TCP  172.16.131.244:80                 2       10       10      846     1098
          -> 192.168.37.51:80                     1        5        5        423      549
          -> 192.168.37.52:80                     1        5        5        423      549


 模拟pc51 web服务故障：
        [root@pc51 ~]# systemctl  stop httpd 
        [root@pc50 ~]# ipvsadm -Z


//客户端测试
        # elinks --dump http://172.16.131.244/test.html
           192.168.4.52
        # elinks --dump http://172.16.131.244/test.html
           192.168.4.52


        [root@pc50 ~]# ipvsadm -Ln --stats
        IP Virtual Server version 1.2.1 (size=4096)
        Prot LocalAddress:Port               Conns   InPkts  OutPkts  InBytes OutBytes
          -> RemoteAddress:Port
        TCP  172.16.131.244:80                 3       11       11      906     1138
          -> 192.168.4.51:80                     1        1        1         60       40
          -> 192.168.4.52:80                     2       10       10      846     1098