1. 准备4台新装的系统，每台都有2个网卡。
2. 重新编译内核，加入对carp等的支持
fb01# cd /usr/src/sys/i386/conf
fb01# cp GENERIC UNIXNOTES
3. 加下面的内容到新的UNIXNOTES内核编辑文件
#new add
device carp #Common Address Redundancy Protocol
device pf #PF OpenBSD packet-filter firewall
device pflog #logging support interface for PF
device pfsync #synchronization interface for PF
options ALTQ
options ALTQ_CBQ
options ALTQ_RED
options ALTQ_RIO
options ALTQ_HFSC
options ALTQ_PRIQ
options ALTQ_NOPCC
4. Build 和install 新的itkylin.com内核参考
5. 在一台机器上编译好内核之后直接scp到别的机器上启用即可.
fb01# cd /boot/kernel
6. 在每台机器上用port安装apache,可以只在一台机器上编译，然后scp到其他上直接pkgadd.
7. 编辑每台机器的rc.conf 文件
fb01# cat /etc/rc.conf
sshd_enable=”YES”
ifconfig_le0=”inet 172.20.6.201 netmask 255.255.255.0″
ifconfig_le1=”inet 192.168.1.201 netmask 255.255.255.0″
defaultrouter=”172.20.6.2″
hostname=”fb01.abc.com”
cloned_interfaces=”carp0 carp1 carp2 carp3″
ifconfig_carp0=”vhid 1 advbase 5 advskew 10 pass aaa123 172.20.6.205/24″
ifconfig_carp1=”vhid 2 advbase 5 advskew 20 pass aaa123 172.20.6.206/24″
ifconfig_carp2=”vhid 3 advbase 5 advskew 30 pass aaa123 172.20.6.207/24″
ifconfig_carp3=”vhid 4 advbase 5 advskew 40 pass aaa123 172.20.6.208/24″
ifconfig_pfsync0=”up syncif le1″
apache22_enable=”YES”
fb02# cat /etc/rc.conf
sshd_enable=”YES”
ifconfig_le0=”inet 172.20.6.202 netmask 255.255.255.0″
ifconfig_le1=”inet 192.168.1.202 netmask 255.255.255.0″
defaultrouter=”172.20.6.2″
hostname=”fb02.abc.com”
cloned_interfaces=”carp0 carp1 carp2 carp3″
ifconfig_carp0=”vhid 1 advbase 5 advskew 40 pass aaa123 172.20.6.205/24″
ifconfig_carp1=”vhid 2 advbase 5 advskew 10 pass aaa123 172.20.6.206/24″
ifconfig_carp2=”vhid 3 advbase 5 advskew 20 pass aaa123 172.20.6.207/24″
ifconfig_carp3=”vhid 4 advbase 5 advskew 30 pass aaa123 172.20.6.208/24″
ifconfig_pfsync0=”up syncif le1″
fb03# cat /etc/rc.conf
gateway_enable=”YES”
hostname=”fb01.abc.com”
sshd_enable=”YES”
ifconfig_le0=”inet 172.20.6.203 netmask 255.255.255.0″
ifconfig_le1=”inet 192.168.1.203 netmask 255.255.255.0″
defaultrouter=”172.20.6.2″
hostname=”fb03.abc.com”
apache22_enable=”YES”
cloned_interfaces=”carp0 carp1 carp2 carp3″
ifconfig_carp0=”vhid 1 advbase 5 advskew 30 pass aaa123 172.20.6.205/24″
ifconfig_carp1=”vhid 2 advbase 5 advskew 40 pass aaa123 172.20.6.206/24″
ifconfig_carp2=”vhid 3 advbase 5 advskew 10 pass aaa123 172.20.6.207/24″
ifconfig_carp3=”vhid 4 advbase 5 advskew 20 pass aaa123 172.20.6.208/24″
ifconfig_pfsync0=”up syncif le1″
fb04# cat /etc/rc.conf
gateway_enable=”YES”
hostname=”fb01.abc.com”
sshd_enable=”YES”
ifconfig_le0=”inet 172.20.6.204 netmask 255.255.255.0″
ifconfig_le1=”inet 192.168.1.204 netmask 255.255.255.0″
defaultrouter=”172.20.6.2″
hostname=”fb04.abc.com”
apache22_enable=”YES”
cloned_interfaces=”carp0 carp1 carp2 carp3″
ifconfig_carp0=”vhid 1 advbase 5 advskew 20 pass aaa123 172.20.6.205/24″
ifconfig_carp1=”vhid 2 advbase 5 advskew 30 pass aaa123 172.20.6.206/24″
ifconfig_carp2=”vhid 3 advbase 5 advskew 40 pass aaa123 172.20.6.207/24″
ifconfig_carp3=”vhid 4 advbase 5 advskew 10 pass aaa123 172.20.6.208/24″
ifconfig_pfsync0=”up syncif le1″
8. 为每个apache编写主页文件，类似下面
fb01# cat /usr/local/www/apache22/data/index.html
<html><body><h1>201 It works!</h1></body></html>
9. 为每个机器加入下面语句，以是carp级别高会自动拿回master
fb04# cat /etc/sysctl.conf
net.inet.carp.preempt=1
net.inet.carp.arpbalance=1
10. 各个机器重启之后的网卡状态，只看carp部分
fb01# ifconfig
carp0: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.205 netmask 0xffffff00
carp: MASTER vhid 1 advbase 5 advskew 10
carp1: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.206 netmask 0xffffff00
carp: BACKUP vhid 2 advbase 5 advskew 20
carp2: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.207 netmask 0xffffff00
carp: BACKUP vhid 3 advbase 5 advskew 30
carp3: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.208 netmask 0xffffff00
carp: BACKUP vhid 4 advbase 5 advskew 40
fb02# ifconfig
carp0: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.205 netmask 0xffffff00
carp: BACKUP vhid 1 advbase 5 advskew 40
carp1: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.206 netmask 0xffffff00
carp: MASTER vhid 2 advbase 5 advskew 10
carp2: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.207 netmask 0xffffff00
carp: BACKUP vhid 3 advbase 5 advskew 20
carp3: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.208 netmask 0xffffff00
carp: BACKUP vhid 4 advbase 5 advskew 30
fb03# ifconfig
carp0: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.205 netmask 0xffffff00
carp: BACKUP vhid 1 advbase 5 advskew 30
carp1: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.206 netmask 0xffffff00
carp: BACKUP vhid 2 advbase 5 advskew 40
carp2: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.207 netmask 0xffffff00
carp: MASTER vhid 3 advbase 5 advskew 10
carp3: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.208 netmask 0xffffff00
carp: BACKUP vhid 4 advbase 5 advskew 20
fb04# ifconfig
carp0: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.205 netmask 0xffffff00
carp: BACKUP vhid 1 advbase 5 advskew 20
carp1: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.206 netmask 0xffffff00
carp: BACKUP vhid 2 advbase 5 advskew 30
carp2: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.207 netmask 0xffffff00
carp: BACKUP vhid 3 advbase 5 advskew 40
carp3: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
inet 172.20.6.208 netmask 0xffffff00
carp: MASTER vhid 4 advbase 5 advskew 10
11. 通过别的机器来检查carp工作情况
分别访问http://172.20.6.205 ;http://172.20.6.206; http://172.20.6.207;http://172.20.6.208
得到返回页分别是fb01,fb02,fb03,fb04 上的apache页面，因为4台同时在线，即访问每carp优先级最高的。
12. 重启fb01之后，在访问http://172.20.6.205，将有别的机器接管master