lvs/NAT的实现及脚本（图）

VS/NAT

LVS-NAT基于cisco的LocalDirector。VS/NAT不需要在RealServer上做任何设置，其只要能提供一个tcp/ip的协议栈即可，甚至其无论基于什么OS。基于VS/NAT，所有的入站数据包均由Director进行目标地址转换后转发至内部的RealServer，RealServer响应的数据包再由Director转换源地址后发回客户端。

VS/NAT模式不能与netfilter兼容，因此，不能将VS/NAT模式的Director运行在netfilter的保护范围之中。现在已经有补丁可以解决此问题，但尚未被整合进ip_vs code。

____________

| |

| client |

|____________|

CIP=192.168.0.253 (eth0)

|

|

VIP=192.168.0.220 (eth0)

____________

| |

| director |

|____________|

DIP=192.168.10.10 (eth1)

|

(switch)------------------------

| |

RIP=192.168.10.2 (eth0) RIP=192.168.10.3 (eth0)

_____________ _____________

| | | |

| realserver1 | | realserver2 |

|_____________| |_____________|

设置VS/NAT模式的LVS(这里以web服务为例)

Director:

建立服务

# ipvsadm -A -t VIP:PORT -s rr

如:

# ipvsadm -A -t 192.168.0.220:80 -s rr

设置转发：

# ipvsadm -a -t VIP:PORT -r RIP_N:PORT -m -w N

如：

# ipvsadm -a -t 192.168.0.220:80 -r 192.168.10.2 -m -w 1

# ipvsadm -a -t 192.168.0.220:80 -r 192.168.10.3 -m -w 1

打开路由转发功能

# echo "1" > /proc/sys/net/ipv4/ip_forward

服务控制脚本：

#!/bin/bash

#

# LVS script for VS/NAT

#

. /etc/rc.d/init.d/functions

#

VIP=192.168.0.220

DIP=192.168.10.10

RIP1=192.168.10.2

RIP2=192.168.10.3

#

case "$1" in

start)

/sbin/ifconfig eth0:1 $VIP netmask 255.255.255.0 up

# Since this is the Director we must be able to forward packets

echo 1 > /proc/sys/net/ipv4/ip_forward

# Clear all iptables rules.

/sbin/iptables -F

# Reset iptables counters.

/sbin/iptables -Z

# Clear all ipvsadm rules/services.

/sbin/ipvsadm -C

# Add an IP virtual service for VIP 192.168.0.219 port 80

# In this recipe, we will use the round-robin scheduling method.

# In production, however, you should use a weighted, dynamic scheduling method.

/sbin/ipvsadm -A -t $VIP:80 -s rr

# Now direct packets for this VIP to

# the real server IP (RIP) inside the cluster

/sbin/ipvsadm -a -t $VIP:80 -r $RIP1 -m

/sbin/ipvsadm -a -t $VIP:80 -r $RIP2 -m

;;

stop)

# Stop forwarding packets

echo 0 > /proc/sys/net/ipv4/ip_forward

# Reset ipvsadm

/sbin/ipvsadm -C

# Bring down the VIP interface

ifconfig eth0:1 down

;;

*)

echo "Usage: $0 {start|stop}"

;;

esac
本文出自 “一份存档” 博客，请务必保留此出处http://linuxbpm.blog.51cto.com/1823930/388233