实验结构图：
系统环境：
VMWare ESXi
CentOS 5.2
Apache
qmail
LVS 实现方式: DR
DR是指Direct Routing，它的转发流程是：Director机器收到外界请求，按相应的调度算法将其直接发送到相应Real Server，Real Server处理完该请求后，将结果数据包直接返回给客户，完成一次负载调度。
需要的软件包：ipvsadm-1.24-8.1
网络配置：
LD Server eth0 10.0.10.209
Real Server1 eth0 10.0.10.207
Real Server2 eth0 10.0.10.208
Real Server3 eth0 10.0.10.210
Real Server4 eth0 10.0.10.240
VIP 10.0.10.60
VIP2 10.0.10.61
用户请求http连接是指向10.0.10.60，LD Server通过权重轮询（wrr）调度，将http请求转发到Real Server群中。
LVS的配置是通过前面所安装的IP虚拟服务器软件ipvsadm来实现的。ipvsadm与LVS的关系类似于iptables和NetFilter的关系，前者只是一个建立和修改规则的工具，这些命令的作用在系统重新启动后就消失了，所以应该将这些命令写到一个脚本里，然后让它在系统启动后自动执行。
LD Server 启动脚本：/etc/init.d/lvsDR
#!/bin/sh
#
# description: start LVS of Director Server
# created in 2009-04-29 by Dika.Ye
VIP=10.0.10.60
VIP2=10.0.10.61
RIP1=10.0.10.207
RIP2=10.0.10.208
RIP3=10.0.10.210
RIP4=10.0.10.240
#RIP3=10.0.10.x
GW=10.0.10.254
SER_PORT=80
SMTP_PORT=25
HTTP_CON_INTERFACE=eth0:6721
SMTP_CON_INTERFACE=eth0:6725
ATTEM=wrr
# Source function library.
. /etc/rc.d/init.d/functions
case $1 in
start)
echo -n "Starting LVS of Director Server "
#Set the Virtual IP Address
/sbin/ifconfig $HTTP_CON_INTERFACE $VIP broadcast $VIP netmask 255.255.255.255 up
/sbin/ifconfig $SMTP_CON_INTERFACE $VIP2 broadcast $VIP2 netmask 255.255.255.255 up
/sbin/route add -host $VIP dev $HTTP_CON_INTERFACE
/sbin/route add -host $VIP2 dev $SMTP_CON_INTERFACE
#Clear IPVS Table
/sbin/ipvsadm -C
#Set Lvs for http
/sbin/ipvsadm -A -t $VIP:$SER_PORT -s $ATTEM
/sbin/ipvsadm -a -t $VIP:$SER_PORT -r $RIP1:$SER_PORT -g
#Set LVS for smtp
/sbin/ipvsadm -A -t $VIP2:$SMTP_PORT -s $ATTEM
/sbin/ipvsadm -a -t $VIP2:$SMTP_PORT -r $RIP3:$SMTP_PORT -g
/sbin/ipvsadm -a -t $VIP2:$SMTP_PORT -r $RIP4:$SMTP_PORT -g
#Run Lvs
/sbin/ipvsadm
echo "."
;;
stop)
echo -n "Close LVS Director Server "
/sbin/ifconfig $HTTP_CON_INTERFACE down
/sbin/ifconfig $SMTP_CON_INTERFACE down
/sbin/ipvsadm -C
echo "."
;;
status)
echo "IPVSADM list"
ipvsadm -Ln
;;
*)
echo "Usage: $0" {start|stop}
exit 1
esac
Real Server启动脚本：/etc/init.d/lvsRS
HTTP Real Server
#!/bin/sh
# decription:start realserver
# chkconfig 235 26 26
VIP=10.0.10.60
VIP2=10.0.10.61
RIP1=10.0.10.207
RIP2=10.0.10.208
RIP3=10.0.10.210
RIP4=10.0.10.240
#RIP3=10.0.10.x
GW=10.0.10.254
SER_PORT=80
SMTP_PORT=25
HTTP_CON_INTERFACE=lo:6721
SMTP_CON_INTERFACE=lo:6725
ATTEM=wrr
. /etc/rc.d/init.d/functions
case "$1" in
start)
echo " start LVS of REALServer"
/sbin/ifconfig $HTTP_CON_INTERFACE $VIP broadcast $VIP netmask 255.255.255.255 up
/sbin/route add -host $VIP dev $HTTP_CON_INTERFACE
echo "0" > /proc/sys/net/ipv4/ip_forward
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
;;
stop)
/sbin/ifconfig $HTTP_CON_INTERFACE down
echo " stop LVS service"
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
;;
*)
echo "Usage: $0 {start|stop}"
exit 1
esac
Real Server启动脚本：/etc/init.d/lvsRS
SMTP Real Server
#!/bin/sh
# decription:start realserver
# chkconfig 235 26 26
VIP=10.0.10.60
VIP2=10.0.10.61
RIP1=10.0.10.207
RIP2=10.0.10.208
RIP3=10.0.10.210
RIP4=10.0.10.240
#RIP3=10.0.10.x
GW=10.0.10.254
SER_PORT=80
SMTP_PORT=25
HTTP_CON_INTERFACE=lo:6721
SMTP_CON_INTERFACE=lo:6725
ATTEM=wrr
. /etc/rc.d/init.d/functions
case "$1" in
start)
echo " start LVS of REALServer"
/sbin/ifconfig $SMTP_CON_INTERFACE $VIP2 broadcast $VIP2 netmask 255.255.255.255 up
/sbin/route add -host $VIP2 dev $SMTP_CON_INTERFACE
echo "0" > /proc/sys/net/ipv4/ip_forward
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
;;
stop)
/sbin/ifconfig $SMTP_CON_INTERFACE down
echo " stop LVS service"
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
;;
*)
echo "Usage: $0 {start|stop}"
exit 1
esac
启动服务：
LD Server
# service lvsDR start
Real Server
# service lvsRS start
[/img]..
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