通过keepalived搭建LVS高可用集群
实验环境：
主Director Server 192.168.163.3
备Director Server 192.168.163.4
real server1 192.168.163.5
real server2 192.168.163.6
VIP 192.168.163.100
四个节点上都安装上webserver：
#yum -y install httpd
在Director上安装好LVS软件和keepalived软件
LVS下载地址：http://www.linuxvirtualserver.org/software/ipvs.html
keepalived官网：http://www.keepalived.org
1.源码安装：
安装LVS
#tar -zxvf ipvsadm-1.24.tar.gz #cd ipvsadm-1.24 #make #make install
安装keepalived
#tar -zxvf keepalived-1.1.19.tar.gz #cd keepalived-1.1.19 #./configure --sysconf=/etc --with-kerner-dir=/usr/src/kernels/2.6.18-8.el5-i686 #make #make install
2.yum源安装：
#yum -y install ipvsadm #yum -y install keepalived
编辑keepalived的配置文件（/etc/keepalived/keepalived.conf）主要由3部分组成，分别为全局定义，vrrp实例定义，虚拟服务器定义
#全局定义
global_defs {
#设置报警邮件地址，可以多个，每行一个
notification_email {
root@localhost
}
#设置邮件发送地址
notification_email_from keepalived@localhost
#设置smtp server地址
smtp_server 127.0.0.1
#设置smtp server连接超时时间
smtp_connect_timeout 30
#表示运行keepalived服务器的一个标识
router_id LVS_DEVEL
}
#完成keepalived的手动切换
vrrp_script chk_schedown {
script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
interval 2
weight -2
}
#vrrp实例定义
vrrp_instance VI_1 {
state MASTER #定义keepalived角色，备节点为BACKUP
interface eth0
#指定HA监测的网络接口
virtual_router_id 51
#虚拟路由标识，主备要一致
priority 100 #优先级，数字越大优先级越高，备节点小于主节点
advert_int 1
#主备节点同步检查时间间隔，单位为秒
authentication {
auth_type PASS
#设置认证类型，主要由PASS和AH
auth_pass keepalivedpass
#设置认证密码，同一个实例下，主备节点要一致
}
virtual_ipaddress { #虚拟IP，可以多个，每行一个
192.168.163.100/24 dev eth0 label eth0:0
}
track_script {
#要执行的脚本
chk_schedown
}
}
#虚拟服务器定义
virtual_server 192.168.163.100 80 {
#定义虚拟服务器IP和PROT
delay_loop 6
#设置运行状况检查时间，单位为秒
lb_algo rr
#设置负载均衡调度算法
lb_kind DR
#设置LVS实现负载均衡的机制，有NAT，DR，TU
# persistence_timeout 50
#会话保持时间，单位为秒
protocol TCP
#指定转发协议类型
sorry_server 127.0.0.1 80
#定义所有realserver均出现故障时所用的服务器
real_server 192.168.163.5 80 {
#定义real server的IP和端口
weight 1
#定义权重
HTTP_GET {
#real server的状态检测，还有TCP_CHECK等
url {
#检查的URL地址和应返回的状态码
path /
status_code 200
}
connect_timeout 3
#设置连接超时时间
nb_get_retry 3
#设置重试次数
delay_before_retry 3
#设置重试间隔
}
}
real_server 192.168.163.6 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}在real server上编写脚本完成VIP设置和节点的配置（/etc/init.d/lvsrs）
#!/bin/bash
#
# Script to start LVS DR real server.
# chkconfig: - 90 10
# description: LVS DR real server
#
. /etc/rc.d/init.d/functions
VIP=192.168.163.100
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
启动keepalived+LVS集群系统
在主备Director server上启动keepalived服务
#service keepalived start
在两个real server上启动real server的配置脚本
#service lvsrs start
在四个节点启动httpd服务
#service httpd start