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LVS
LVS是Linux Virtual Server的简写，意即Linux虚拟服务器，是一个虚拟的服务器集群系统。本项目在1998年5月由章文嵩博士成立，是中国国内最早出现的自由软件项目之一。目前有三种IP负载均衡技术（VS/NAT、VS/TUN和VS/DR）本文是按照VS/DR的方式配置,十种调度算法（rrr|wrr|lc|wlc|lblc|lblcr|dh|sh|sed|nq）。 Keepalvied
Keepalived在这里主要用作RealServer的健康状态检查以及LoadBalance主机和BackUP主机之间failover的实现 部署环境
系统：Linux CentOS 5.8
浮动IP：192.168.1.150
主LVS IP：192.168.1.86
备LVS IP：192.168.1.87
真实服务器WEB1 IP：192.168.1.88
真实服务器WEB2 IP：192.168.1.250 配置步骤 主备LVS下载软件包
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$>wget /software/kernel-2.6/ipvsadm-1.24.tar.gz $>wget /software/keepalived-1.1.15.tar.gz
主备LVS安装LVS和Keepalived
$>lsmod |grep ip_vs $>uname -r 2.6.18-53.el5PAE $>ln -s /usr/src/kernels/2.6.18-53.el5PAE-i686/ /usr/src/linux $>tar zxvf ipvsadm-1.24.tar.gz $>cd ipvsadm-1.24 $>make && make install $>find / -name ipvsadm # 查看ipvsadm的位置 $>tar zxvf keepalived-1.1.15.tar.gz $>cd keepalived-1.1.15 $>./configure && make && make install $>find / -name keepalived # 查看keepalived位置 $>cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/ $>cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/ $>mkdir /etc/keepalived $>cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/ $>cp /usr/local/sbin/keepalived /usr/sbin/ $>service keepalived start|stop
执行ln -s 出错请看最后的常见问题处理 主备LVS配置Keepalived
修改配置文件/etc/keepalived/keepalived.conf为如下内容（注意真实环境下将#注释说明的内容去掉）
global_defs { notification_email { admin@ } notification_email_from sns-lvs@ smtp_server 127.0.0.1 router_id LVS_DEVEL }
vrrp_instance VI_1 { state MASTER #备份服务器上将MASTER改为BACKUP
interface eth0 virtual_router_id 88 priority 100 # 备份服务上将100改为99 advert_int 1 authentication { auth_type PASS auth_pass 123123 } virtual_ipaddress { 192.168.1.150 #(如果有多个VIP，继续换行填写.) } }
virtual_server 192.168.1.150 80 { delay_loop 3 #(每隔3秒查询realserver状态) lb_algo wrr #(lvs 算法) lb_kind DR #(Direct Route) persistence_timeout 3 #(同一IP的连接3秒内被分配到同一台realserver) protocol TCP #(用TCP协议检查realserver状态)
real_server 192.168.1.88 80 {weight 3 #(权重)TCP_CHECK {connect_timeout 10 #(10秒无响应超时)nb_get_retry 3delay_before_retry 3connect_port 80}}real_server 192.168.1.250 80 {weight 3TCP_CHECK {connect_timeout 10nb_get_retry 3delay_before_retry 3connect_port 80}}
}
配置提供真实服务的主机
添加配置文件/etc/realserver/realserver.sh为以下内容
#!/bin/bash
SNS_VIP=192.168.1.150
/etc/rc.d/init.d/functions
case "$1" in start) /sbin/ifconfig lo:0 $SNS_VIP netmask 255.255.255.255 broadcast $SNS_VIP up /sbin/route add -host $SNS_VIP dev lo:0 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 sysctl -p >/dev/null 2>&1 echo "RealServer Start OK" ;;
stop) /sbin/ifconfig lo:0 down /sbin/route del $SNS_VIP >/dev/null 2>&1 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 "RealServer Stoped" ;;
*) echo "Usage: $0 {start|stop}" exit 1 esac
exit 0
提供真实服务的主机修改/etc/rc.d/rc.loal
$>vi /etc/rc.d/rc.local
添加 /etc/realserver/realserver.sh 主备LVS执行
$>chkconfig --level keepalived 35 on
主备LVS启动keepalived服务
$>/etc/init.d/keepalived start
提供真实服务的主机运行/etc/realserver/realserver.sh
$>chmod +x /etc/realserver/realserver.sh $>/etc/realserver/realserver.sh
9.查看当前LVS的状态
$>ipvsadm -ln
常见问题处理：
安装时发现没有目录：/usr/src/kernels，安装kernel-devel包可以解决
$>yum install kernel-devel
安装编译keeepalived时需要支持LVS时才可以做LVS调度：例如出现下面情况，将不支持lvs
Keepalived configuration
Keepalived version : 1.1.15 Compiler : gcc Compiler flags : -g -O2 Extra Lib : -lpopt -lssl -lcrypto Use IPVS Framework : No IPVS sync daemon support : No Use VRRP Framework : Yes Use LinkWatch : No Use Debug flags : No
解决办法，指定kernel目录：
/configure —with-kernel-dir=/usr/src/kernels/2.6.9-55.EL-i686 （rhel4.5_32平台） ./configure —with-kernel-dir=/usr/src/kernels/2.6.18-164.el5-i686/（rhel5.4_32平台）
正确情况：
Keepalived configuration
Keepalived version : 1.1.15 Compiler : gcc Compiler flags : -g -O2 Extra Lib : -lpopt -lssl -lcrypto Use IPVS Framework : Yes IPVS sync daemon support : Yes Use VRRP Framework : Yes Use LinkWatch : No Use Debug flags : No
然后在make，make install
安装编译keeepalived时
configure: error: !!! OpenSSL is not properly installed on your system. !!! !!! Can not include OpenSSL headers files. !!!
$>yum install e2fsprogs-devel keyutils-libs-devel libsepol-devel libselinux-devel krb5-devel zlib-devel openssl-devel
参考资料：
http://i-/blog/1684342 官方文档： /documentation.html
