LVS负载均衡NAT模式单网卡、相同网段的简单部署

实验环境：centos7、关闭防火墙、关闭SElinux

yum -y install ipvsadm

[root@localhost ~]# echo "net.ipv4.ip_forward = 1" >> /etc/sysctl.conf
[root@localhost ~]# cat /etc/sysctl.conf 
# sysctl settings are defined through files in
# /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/.
#
# Vendors settings live in /usr/lib/sysctl.d/.
# To override a whole file, create a new file with the same in
# /etc/sysctl.d/ and put new settings there. To override
# only specific settings, add a file with a lexically later
# name in /etc/sysctl.d/ and put new settings there.
#
# For more information, see sysctl.conf(5) and sysctl.d(5).
net.ipv4.ip_forward = 1

[root@localhost ~]# modprobe ip_vs
[root@localhost ~]# cat /proc/net/ip_vs
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port Forward Weight ActiveConn InActConn

[root@localhost ~]# ipvsadm -C   #清除内核虚拟服务器表中的所有记录
[root@localhost ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
[root@localhost ~]# ipvsadm -A -t 10.5.6.61:80 -s rr     #添加虚拟服务器
[root@localhost ~]# ipvsadm -a -t 10.5.6.61:80 -r 10.5.6.62:80 -m  #添加服务器节点
[root@localhost ~]# ipvsadm -a -t 10.5.6.61:80 -r 10.5.6.63:80 -m  #添加服务器节点
[root@localhost ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.5.6.61:80 rr
  -> 10.5.6.62:80                 Masq    1      0          3         
  -> 10.5.6.63:80                 Masq    1      0          3 

选项注释
“-A”:表示添加虚拟服务器
“-a”:表示添加真实服务器
“-t”:用来指定VIP地址及TCP端口
“-r”:用来指定RIP地址及TCP端口
“-s”:用来指定负载调度算法——rr（轮询）、wrr（加权轮询）、lc（最少连接）、wlc（加权最少连接）
“-m”:表示使用NAT群集模式（是DR模式，是TUN模式）

以下配置两台真实服务器都要做

vim /etc/sysconfig/network-scripts/ifcfg-ens192

TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=ens192
UUID=818b65d8-d309-48f7-a609-9b9920404a12
DEVICE=ens192
ONBOOT=yes
IPADDR=10.5.6.62
PREFIX=24
GATEWAY=10.5.6.61   #网关指向虚拟服务器
DNS1=114.114.114.114
IPV6_PRIVACY=no

[root@localhost ~]# yum -y install httpd
...
[root@localhost ~]# vim /var/www/html/index.html
添加:
server01

[root@localhost ~]# curl 10.5.6.61
server 01
[root@localhost ~]# curl 10.5.6.61
server 02
[root@localhost ~]# curl 10.5.6.61
server 01
[root@localhost ~]# curl 10.5.6.61
server 02
[root@localhost ~]# curl 10.5.6.61
server 01
[root@localhost ~]# curl 10.5.6.61
server 02
[root@localhost ~]# curl 10.5.6.61
server 01
[root@localhost ~]# curl 10.5.6.61
server 02
[root@localhost ~]# curl 10.5.6.61

这不就是单臂路由吗？哈哈