环境：
    director：192.168.232.18:80(centos7)
    realserver1：192.168.232.30:80(centos7)
    realserver2：192.168.232.31:80(centos7)
    client：192.168.232.101
    
    VIP：192.168.232.20:80
director配置
[root@director~]# echo "net.ipv4.ip_forward = 1" >> /etc/sysctl.conf 
[root@director~]# ifconfig eth0:2 192.168.232.21/24 up
[root@director~]# vim /etc/sysconfig/ipvsadm 
-A -t 192.168.232.20:80 -s wrr
-a -t 192.168.232.20:80 -r 192.168.232.30:80 -i -w 2
-a -t 192.168.232.20:80 -r 192.168.232.31:80 -i -w 2
[root@director~]# /etc/init.d/ipvsadm restart
[root@director~]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.232.20:80 wrr
  -> 192.168.232.30:80            Tunnel  2      0          0         
  -> 192.168.232.31:80            Tunnel  2      0          0  
realserver配置(两台所做配置相同)
[root@realserver1~]# modprobe ipip
[root@realserver1~]# lsmod | grep ipip
ipip                   13472  0 
tunnel4                13252  1 ipip
ip_tunnel              23760  1 ipip
[root@realserver1~]# vim /etc/sysconfig/network-scripts/ifcfg-tunl0
DEVICE=tunl0
IPADDR=192.168.232.20
NETMASK=255.255.255.255
ONBOOT=yes
NAME=tunl0
[root@realserver1~]# systemctl restart network.service
[root@realserver1~]# vim /etc/sysctl.conf
net.ipv4.ip_forward = 0
net.ipv4.conf.tunl0.arp_ignore = 1
net.ipv4.conf.tunl0.arp_announce = 2
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
net.ipv4.conf.tunl0.rp_filter = 0
net.ipv4.conf.all.rp_filter = 0
[root@realserver1~]# sysctl -p