利用LVS+Keepalived实现高性能高可用负载均衡服务器

1、LVS+Keepalived 介绍LVSLVS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);十种调度算法(rrr|wrr|lc|wlc|lblc|lblcr|dh|sh|sed|nq)。KeepalviedKeepalived 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 的实现二.网站负载均衡拓朴图IP信息列表

2、：名称IPLVS-DR-Master LVS-DR-BACKUP LVS-DR-VIP WEB1-Realserver WEB2-Realserver 0 GateWay 复制代码三.安装LVS和Keepalvied 软件包1. 下载相关软件包#mkdir /usr/local/src/lvs #cd /usr/local/src/lvs #wgethttp:/www.linuxvirtualserver.Org/software/kernel

3、-2.6/ipvsadm-1.24.tar.gz #wget http:/www.keepalived.0rg/software/keepalived-1.1.15.tar.gz复制代码2. 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

4、 #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/sy

5、sconfig/, #mkdir /etc/keepalived #cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/ #cp /usr/local/sbin/keepalived /usr/sbin/ #service keepalived start|stop #做成系统启动服务方便管理 .复制代码四.配置LVS实现负载均衡1 . LVS-DR,配置LVS脚本实现负载均衡注：此脚本在于演示方便大家理解lvs,在keepalived方案中不要启动此脚本，所以看后面有注掉，很多朋友对此有问题。关于LVS的keepalvie

6、d 的HA方案，完全由keepalived.conf一个文件搞定，特此声明！#vi /usr/local/sbin/lvs-dr.sh #!/bin/bash # description: start LVS of DirectorServer #Written by :NetSeek , GW= # website director vip. SNS_VIP= SNS_RIP1= SNS_RIP2=0. ./etc/rc.d/init.d/funct

7、ions logger $0 called with $1 , case "$1" in, start) # set squid vip /sbin/ipvsadm -set 30 5 60 /sbin/ifconfig eth0:0 $SNS_VIP broadcast $SNS_VIP netmask 55broadcast $SNS_VIP up /sbin/route add -host $SNS_VIP dev eth0:0 /sbin/ipvsadm -A -t $SNS_VIP:80 -s wrr -p 3 /sbin/ipvsadm

8、 -a -t $SNS_VIP:80 -r $SNS_RIP1:80 -g -w 1 /sbin/ipvsadm -a -t $SNS_VIP:80 -r $SNS_RIP2:80 -g -w 1 touch /var/lock/subsys/ipvsadm >/dev/null 2>&1； stop) /sbin/ipvsadm -C /sbin/ipvsadm -Z ifconfig eth0:0 down route del $SNS_VIP, rm -rf /var/lock/subsys/ipvsadm >/dev/null 2>&1 echo

9、 "ipvsadm stoped",;, status), if ! -e /var/lock/subsys/ipvsadm ;then echo "ipvsadm stoped" exit 1 else echo "ipvsadm OK” fi；, *) echo "Usage: $0 (start|stop|status" exit 1 esac, exit 0复制代码2.配置 Realserver 脚本.#vi /usr/local/sbin/realserver.sh #!/bin/bash # descriptio

10、n: Config realserver lo and apply noarp #Written by :NetSeek , SNS_VIP= . /etc/rc.d/init.d/functions, case "$1" in start) ifconfig lo:0 $SNS_VIP netmask 55 broadcast $SNS_VIP /sbin/route add -host $SNS_VIP dev lo:0 echo "1" >/pro

11、c/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>&1echo "RealServer Start OK" stop)

12、, ifconfig lo:0 down 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/a

13、ll/arp_announce echo "RealServer Stoped", *) echo "Usage: $0 start|stop" exit 1 esac exit 0复制代码或者采用 secondary ip address 方式配置 vi /etc/sysctl.confnet.ipv4.conf.lo.arp_ignore = 1 net.ipv4.conf.lo.arp_announce = 2 net.ipv4.conf.all.arp_ignore = 1 net.ipv4.conf.all.arp_announce = 2 c

14、ode #sysctl ?p #ip addr add /32 dev lo #ip add list查看是否绑定 3. 启动lvs-dr 脚本和realserver 启本，在 DR上可以查看LVS当前状态： #watch ipvsadm ?ln复制代码五.利用Keepalvied实现负载均衡和和高可用性1.配置在主负载均衡服务器上配置keepalived.conf#vi /etc/keepalived/keepalived.conf! Configuration File for keepalived, global_defs notification_email c

15、nseek, notification_email_from sns-lvs smtp_server # smtp_connect_timeout 30router_id LVS_DEVEL# 20081013 written by :netseek# VIP1vrrp_instance VI_1 state MASTER #备份服务器上将 MASTE畋为BACKUPinterface eth0virtual_router_id 51priority 100 # 备份服务上将 100改为99advert_int 1authentication auth_type PASSa

16、uth_pass 1111virtual_ipaddress #（如果有多个VIP，继续换行填写.）virtual_server 80 delay_loop 6 #（ 每隔 10 秒查询 realserver 状态）lb_algo wrr #（lvs 算法）lb_kind DR #（Direct Route）persistence_timeout 60 #（ 同一 IP 的连接 60 秒内被分配到同一台realserver）protocol TCP #（ 用 TCP协议检查 realserver 状态）real_server 61.164.12

17、2.9 80 weight 3 #（ 权重）TCP_CHECKconnect_timeout 10 #（10秒无响应超时）nb_get_retry 3delay_before_retry 3connect_port 80real_server 0 80 weight 3TCP_CHECKconnect_timeout 10nb_get_retry 3delay_before_retry 3connect_port 80 , 复制代码Ivs再按装keepalived,仍后配置,只需将红色标示的部分改一下即可2. BACKUP服务器同上配置，先安装/etc/keepaliv

18、ed/keepalived.conf3.停掉lvs_dr.sh演示脚本#/usr/local/sbin/lvs-dr.sh#/usr/local/sbin/lvs-dr.sh stop#/etc/init.d/keepalived start keepalived.conf配置文件,整个LVS负均衡HA方案，由vi /etc/rc.local将lvs-dr.sh这个脚本注释掉。停止lvs-dr 脚本启动keepalived 服务，keepalived 就能利用实现负载均衡和高可用keepalived.conf一个文件即可搞定！4.查看lvs服务是否正常#watch ipvsadm ?lnIP

19、Virtual Server version 1.2.1 (size=4096) Prot LocalAddressort Scheduler Flags -> RemoteAddressort Forward Weight ActiveConn InActConn TCP :80 wrr persistent 60 -> 0:80 Route 3 0 0 -> :80 Route 3 0 0复制代码#tail ?f /var/log/message 监听日志，查看状态，测试LVS负载均衡及高可用性是否有

20、效。5.停Master服务器的keepalived服务，查看BAKCUP艮务器是否能正常接管服务。四.相关参考1 . LVS基础知识汇总LVS 的算法介绍/viewthread.php?tid=69学习 LVS 的三种转发模式/viewthread.php?tid=77LVS 中的 IP 负载均衡技术 /viewthread.php?tid=68更多的请到 负载均衡版查看Keepalived 相关参考资料。/documentation.ht