前提：後端兩個RS已經安裝好了httpd，並且可以被正常訪問到
規劃：
Director1：
eth0,DIP:202.207.178.6
eth0:0,VIP:202.207.178.4
Director2：
eth0,DIP:202.207.178.7
eth0:0,VIP:202.207.178.4
RS1:
eth0,RIP:202.207.178.8
lo:0,VIP:202.207.178.4
RS2:
eth0,RIP:202.207.178.9
lo:0,VIP:202.207.178.4
一、配置DR模型（注意：RS1和RS2上的網卡別名地址必須在配置好arp_ignore和arp_announce之後纔可配置，爲避免影響，應關閉防火牆和SELinux）
1、按上述IP地址規劃在相應的網卡上配置相應的IP地址
2、配置RS1和RS2對arp的請求響應，以及其對應VIP
RS1：
# sysctl -w net.ipv4.conf.eth0.arp_announce=2
# sysctl -w net.ipv4.conf.all.arp_announce=2
# echo 1 > /proc/sys/net/ipv4/conf/eth0/arp_ignore
# echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
#ifconfig lo:0 202.207.178.4 broadcast 202.207.178.4 netmask
255.255.255.255
RS2：
# echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
# echo 2 > /proc/sys/net/ipv4/conf/eth0/arp_announce
# echo 1 > /proc/sys/net/ipv4/conf/eth0/arp_ignore
# echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
# ifconfig lo:0 202.207.178.4 broadcast 202.207.178.4 netmask
255.255.255.255
3、爲了使響應報文的源地址爲VIP，添加一條路由
RS1:
# route add -host 202.207.178.4 dev lo:0
RS2:
# route add -host 202.207.178.4 dev lo:0
4、在前端兩個Director上分別定義規則
# ipvsadm -A -t 202.207.178.4:80 -s rr
# ipvsadm -a -t 202.207.178.4:80 -r 202.207.178.8 -g
# ipvsadm -a -t 202.207.178.4:80 -r 202.207.178.9 -g
二、安裝配置keepalived，並對此係統進行測試！
Director1:
1、安裝keepalived
# tar xf keepalived-1.2.1.tar.gz
# cd keepalived-1.2.1
# ./configure --with-kernel-dir=/usr/src/kernels/2.6.32-642.11.1.el6.i686/
# make && make install
注意：
可能需要安裝此包：
# yum install popt-devel
發現/usr/src/kernels/爲空，需要安裝內核源碼
# yum install kernel-devel
2、配置keepalived
1）設置一個變量
# DIR=/usr/local/
2）執行如下語句，將keepalived的配置文件放置在/etc下相關目錄中
# cp $DIR/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
# cp $DIR/etc/sysconfig/keepalived /etc/sysconfig/ && mkdir -p
/etc/keepalived
# cp $DIR/sbin/keepalived /usr/sbin/
3）爲keepalived提供配置文件
# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
#定義出現故障向何處發郵件
notification_email {
}
#定義郵件是由誰發的
notification_email_from root@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
#定義檢測腳本（爲了完成主從節點的切換）
vrrp_script chk_schedown {
script "[ -e /etc/keepalived/down ] && exit 1 || exit 0"
interval 1
weight -5
fail 2
rise 1
}
# VIP1
#用來定義虛擬路由（vrrp實例）
vrrp_instance VI_1 {
state MASTER
#定義通告信息基於那個接口發送和虛擬路由是工作在那個接口上的
interface eth0
# lvs_sync_daemon_inteface eth0
virtual_router_id 51
#定義優先級
priority 101
#定義每隔多長時間發一次通告
advert_int 5
#定義認證
authentication {
#定義認證類型爲簡單字符認證
auth_type PASS
auth_pass keepalivedpass
}
#定義虛擬地址
virtual_ipaddress {
202.207.178.4/16 dev eth0 label eth0:0
}
#定義自己寫的腳本何時執行
track_script {
chk_schedown
}
}
virtual_server 202.207.178.4 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.255.0
protocal TCP
sorry_server 127.0.0.1 80
real_server 202.207.178.8 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
real_server 202.207.178.9 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
}
4）啓動服務
# /etc/init.d/keepalived restart
# ps -ef | grep keepalived
此時發現服務已經啓動！
# tail -fn 100 /var/log/messages
此時發下一直滾屏，是缺少一個模塊，下面加載此模塊
# modprobe ip_vs
# /etc/init.d/keepalived restart
# tail -fn 100 /var/log/messages
此時一切正常
Director2：
配置同主節點，只是在配置文件中修改以下幾項即可：
priority 100
real_server 202.207.178.9 80
測試：此時訪問http://202.207.178.4/，可以發現以輪詢方式訪問到後端RS；在/etc/keepalived下touch一個名爲down的文件，即可實現主從節點的切換！
三、自寫腳本，實現DR宕機，向管理員發郵件（在主從節點上同時執行）
# cd /etc/keepalived/
# vim notify.sh
添加如下內容：
#!/bin/bash
#
contact='root@localhost'
Usage(){
echo "Usage: `basename $0` {master|backup|fault} VIP"
}
Notify(){
subject="`hostname`'s state changed to $1"
mailbody="`data "+%F %T "`: `hostname`'s state change to $1, $VIP floating."
echo $mailbody | mail -s "$subject" $contact
}
[ $# -lt 2 ] && Usage && exit
VIP=$2
case $1 in
master)
Notify master
;;
backup)
Notify backup
;;
fault)
Notify fault
;;
*)
Usage
exit 1
;;
esac
# chmod +x notify.sh
# vim keepalived.conf
在vrrp段添加如下內容：
notify_master "/etc/keepalived/notify.sh master 202.207.178.4"
notify_backup "/etc/keepalived/notify.sh backup 202.207.178.4"
notify_fault "/etc/keepalived/notify.sh fault 202.207.178.4"
此時在兩個節點重啓keepalived服務，實現主從節點切換，即可收到郵件！
歡迎批評指正！