负载均衡：LVS-NAT实现：

负载均衡：LVS-NAT实现：

实验环境：

1 三台RHEL5.4虚拟机，二台作安装好web作为后端Realserver，另一台作为Director，Realserver的网关都指向Director，

2 Director上需要二个网卡，一个公网地址向外提供服务，一个内网地址可以是私有地址与Realserver通信。Director上开启路由转发功能。

3 Realserver ip 192.168.0.55/192.168.0.56，网关192.168.0.100 

  Director ip 外网卡：10.0.0.10，内网卡192.168.0.100 

配置好Realserver上的ip和网关，开启web服务，主要在Director上配置

ipvsadm -A -t 10.0.0.10:80 -s wlc

    ipvsadm -a -t 10.0.0.10：80 -r 192.168.0.55 -m -w 2   

    ipvsadm -a -t 10.0.0.10：80 -r 192.168.0.56 -m -w 5

vim /etc/sysctl

net.ipv4.ip_forward = 1 #开启路由转发

sysctl -p            #重新读取配置文件

用一个客户机直接访问 http://10.0.0.10

 

LVM-nat的脚本

#!/bin/bash

# case “$1”in

start)

    ipvsadm -A -t 192.168.0.83:80 -s wlc

    ipvsadm -a -t 192.168.0.83:80 -r 192.168.10.6 -m -w 2   

    ipvsadm -a -t 192.168.0.83:80 -r 192.168.10.7 -m -w 5 ;;

stop)

    ipvsadm –C ;;

status)

    ipvadm -Ln ;;

esac

ipvsadm –Ln 查看所有连接 ipvsadm –E 192.168.0.83::80 –s wrr (基于权重，权重大的连接将多)

 

负载均衡 LVS-DR server

实验环境：

1 三台RHEL5.4虚拟机，二台作安装好web作为后端Realserver，另一台作为Director

2 Director上需要一个网卡，地址都为公网地址，VIP必须是公网地址，RIP可以是私网地址但要与Director通信时要进行解析。所以这里全部使用公网地址，不需要指定网关

Director上开启路由转发功能。

3 Realserver ip 192.168.0.55/192.168.0.56，

  Director ip 192.168.0.100 VIP 192.168.0.200

当客户端发出请求时reserver都会响应，为避免realserver都响应可以：

1 通过防火墙不让arp数据包进来

2 linux内核有二个参数，配置完后避免arp请求

 

配置过程：

在两个Rserver上各配置vip

 ifconfig lo:0 192.168.0.200 broadcast 192.168.0.200 netmask 255.255.255.255 up

在二个Rserver上配置路由信息通过lo:0接口才出去

route add -host 192.168.0.200 dev lo:0

在二个web服务器上做地址隐藏 vim /etc/sysctl.conf

vim /etc/sysctl.conf 地址隐藏

net.ipv4.conf.lo.arp_ignore = 1

net.ipv4.conf.lo.arp_announce = 2

net.ipv4.conf.all.arp_ignore = 1

net.ipv4.conf.all.arp_announce = 2

sysctl -p 重新读取配置文件

 Directory上配置

ifconfig eth0:0 192.168.0.100 broadcast 192.168.0.100 netmask 255.255.255.255 up

ipvsadm -A -t 192.168.0.200:80 -s wlc

ipvsadm -a -t 192.0.200:80 -r 192.168.0.55 -g -w 5

ipvsadm -a -t 192.0.200:80 -r 192.168.0.56 -g -w 8

server ipvsadm save

二个Realserver可以通过一个nfs服务器共享网站资源，是二个Realserver的网站内容同步提供同样的网站内容

配置完成后直接通过：http://192.168.0.200访问网站 

 

Director脚本:

#!/bin/bash

# LVS script for VS/DR

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

VIP=192.168.0.200

RIP1=192.168.0.55

RIP2=192.168.0.56

PORT=80

case "$1" in

start)          

 /sbin/ifconfig eth0:1 $VIP broadcast $VIP netmask 255.255.255.255 up

 /sbin/route add -host $VIP dev eth0:1

# 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 192.168.0.200 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 wlc

# Now direct packets for this VIP to

# the real server IP (RIP) inside the cluster

 /sbin/ipvsadm -a -t $VIP:80 -r $RIP1 -g -w 1

 /sbin/ipvsadm -a -t $VIP:80 -r $RIP2 -g -w 2

 

 /bin/touch /var/lock/subsys/ipvsadm &> /dev/null

;;

stop)

# Stop forwarding packets

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

# Reset ipvsadm

 /sbin/ipvsadm -C

# Bring down the VIP interface

 /sbin/ifconfig eth0:1 down

 /sbin/route del $VIP

 /bin/rm -f /var/lock/subsys/ipvsadm

 echo "ipvs is stopped..."

;;

status)

 if [ ! -e /var/lock/subsys/ipvsadm ]; then

    echo "ipvsadm is stopped ..."

 else

    echo "ipvs is running ..."

    ipvsadm -L -n

 fi

;;

*)

 echo "Usage: $0 {start|stop|status}"

;;

esac

 

 

RealServer脚本:

#!/bin/bash

# Script to start LVS DR real server.

# description: LVS DR real server

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

VIP=192.168.0.200

host=`/bin/hostname`

case "$1" in

start)

       # Start LVS-DR real server on this machine.

        /sbin/ifconfig lo down

        /sbin/ifconfig lo up

        echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore

        echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce

        echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore

        echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce

        /sbin/ifconfig lo:0 $VIP broadcast $VIP netmask 255.255.255.255 up

        /sbin/route add -host $VIP dev lo:0

;;

stop)

        # Stop LVS-DR real server loopback device(s).

        /sbin/ifconfig lo:0 down

        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore

        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce

        echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore

        echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce

;;

status)

        # Status of LVS-DR real server.

        islothere=`/sbin/ifconfig lo:0 | grep $VIP`

        isrothere=`netstat -rn | grep "lo:0" | grep $VIP`

        if [ ! "$islothere" -o ! "isrothere" ];then

            # Either the route or the lo:0 device

            # not found.

            echo "LVS-DR real server Stopped."

        else

            echo "LVS-DR real server Running."

        fi

;;

*)

            # Invalid entry.

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

            exit 1

;;

esac