负载均衡--LVS+Keepalived

1、利用LVS+Keepalived实现高性能高可用负载均衡作者：NetSeek网站：背景：随着你的网站业务量的增长你网站的服务器压力越来越大？需要负载均衡方案！商业的硬件如F5又太贵，你们又是创业型互联公司如何有效节约成本，节省不必要的浪费？ 同时实现商业硬件一样的高性能高可用的功能？有什么好的负载均衡可伸张可扩展的方案 吗？答案是肯定的！有！我们利用 LVS+Keepalived基于完整开源软件的架构可以为你提供 一个负载均衡及高可用的服务器。一. LVS+Keepalived 介绍1. LVSLVS是Linux Virtual Server的简写

2、，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 );八种调度算法(rr,wrr,lc,wlc,lblc,lblcr,dh,sh )。2. KeepalviedKeepalived在这里主要用作 RealServer的健康状态检查以及LoadBalanee主机和BackUP主机之间failover的实现二. 网站负载均衡拓朴图LinuxTone S>S系统简单负载均衡架构负载肉荀层I务£'故据廉足IP信息列表:名称I

3、PLVS-DR-MasterLVS-DR-BACKUPLVS-DR-VIPWEB1-RealserverWEB2-Realserver0GateWay.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#wget http:/www .linu /software/kernel-2.6/ipvsadm-1.24.ta

4、r.gz#wget http:/www.keepalived.Org/software/keepalived-1.1.15.tar.gz2. 安装 LVS 和 Keepalived#lsmod |grep ip_vs#un ame -r2.6.18-53.el5PAE#ln -s /usr/src/kernels/2.6.18-53.el5PAE-i686/usr/src/li nux#tar zxvf ipvsadm-1.24.tar.gz#cd ipvsadm-1.24#make && make in stall#find / -name ipvsadm # 查看 ipvs

5、adm 的位置#tar zxvf keepalived-1.1.15.tar.gz#cd keepalived-1.1.15#./c on figure&& make && make in stall#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/syscon fig/keepalived /etc/syscon fig/#mkdir /etc/keepalived#cp

6、/usr/local/etc/keepalived/keepalived.c onf /etc/keepalived/#cp /usr/local/sb in/keepalived /usr/sb in/#service keepalived start|stop#做成系统启动服务方便管理四.配置LVS实现负载均衡1 . LVS-DR，配置LVS脚本实现负载均衡#vi /usr/local/sb in/lvs-dr.sh#!/bi n/bash# descripti on: start LVS of DirectorServer#Writte n by :NetSeek http:/www .

7、linuxton GW=# website director vip.SNS_VIP=SNS_RIP1=SNS RIP2=0./etc/rc.d/i nit.d/fu ncti onslogger $0 called with $1case "$1" instart)# set squid vip/sb in/ipvsadm -set 30 5 60/sb in/ifco nfig ethO:O $SNS_VIP broadcast $SNS_VIP netmask 2

8、55 broadcast $SNS_VIP up/sbi n/route add -host $SNS_VIP dev eth0:0/sb in/ipvsadm -A -t $SNS_VIP:80 -s wrr -p 3/sbin/ipvsadm -a -t $SNS_VIP:80 -r $SNS_RIP1:80 -g -w 1/sbi n/ipvsadm -a -t $SNS_VIP:80 -r $SNS_RIP2:80 -g -w 1touch /var/lock/subsys/ipvsadm >/dev/ null 2>&1J Jstop)/s

9、b in/ipvsadm -C/sb in/ipvsadm -Zifconfig eth0:0 downifconfig eth0:1 downroute del $SNS_VIProute del $SS_VIPrm -rf /var/lock/subsys/ipvsadm >/dev/ null 2>&1echo "ipvsadm stoped"status)if ! -e /var/lock/subsys/ipvsadm ;the necho "ipvsadm stoped"exit 1elseecho "ipvsad

10、m OK"fi5 5*)echo "Usage: $0 start|stop|status"exit 1esacexit 02. 配置 Realserver 脚本.#vi /usr/local/sbi n/realserver.sh#!/bin/bash# description: Config realserver lo and apply noarp#Writte n by :NetSeek http:/www .linuxton SNS_VIP=./etc/rc.d/i nit.d/fu ncti onscase "

11、;$1" instart)ifconfig lo:0 $SNS_VIP netmask 55 broadcast $SNS_VIP/sbi n/route add -host $SNS_VIP dev lo:0echo "1" >/proc/sys/net/ipv4/c on f/lo/arp_ig noreecho "2" >/proc/sys/net/ipv4/c on f/lo/arp_a nnounceecho "1" >/proc/sys/net/ipv4/c on f/

12、all/arp_ig noreecho "2" >/proc/sys/net/ipv4/c on f/all/arp_a nnouncesysctl -p >/dev/null 2>&1echo "RealServer Start OK"stop)ifconfig lo:0 dow nroute del $SNS_VIP >/dev/null 2>&1echo "0" >/proc/sys/net/ipv4/c on f/lo/arp_ig noreecho "0"

13、; >/proc/sys/net/ipv4/c on f/lo/arp_a nnounceecho "0" >/proc/sys/net/ipv4/c on f/all/arp_ig noreecho "0" >/proc/sys/net/ipv4/c on f/all/arp_a nnounceecho "RealServer Stoped"*)echo "Usage: $0 start|stop"exit 1esacexit 0或者采用 secondary ip address方式配置# vi

14、 /etc/sysctl.c onfn et.ipv4.c on f.lo.arp_ig nore = 1n et.ipv4.c on f.lo.arp a nnounce = 2n et.ipv4.c on f.all.arp_ig nore = 1n et.ipv4.c on f.all.arp a nnounce = 2#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 -n五.利用Keepalv

15、ied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.co nf#vi /etc/keepalived/keepalived.c onf! Con figurati on File for keepalivedglobal_defs no tificati on _email cn seek# failoverfirewall.loc# sysadm in firewall .locno tificati on _email_from sn s-lvssmtp_server # smtp_c onn ect_timeout 30router_i

16、d LVS_DEVEL# 20081013 written by :netseek# VIP1vrrpn sta nee VI_1 state MASTER#备份服务器上将 MASTER改为BACKUPin terface eth0virtual_router_id 51priority 100#备份服务上将 100改为99advert_ int 1authe nticati on auth_type PASSauth_pass 1111virtual_ipaddress #（如果有多个VIP，继续换行填写.）virtual server 80

17、 delay_loop 6 lb_algo wrr lb kind DRpersiste nce_timeout 60 protocol TCP#（每隔10秒查询realserver状态）#（lvs算法）#（Direct Route）#（同一 IP的连接60秒内被分配到同一台realserver）real_server 80 weight 3TCP_CHECK conn ect_timeout 10n b_get_retry 3 delay_before_retry 3 conn ect_port 80real_server 0 80 weig

18、ht 3TCP_CHECK connect timeout 10#（权重）#（10秒无响应超时）n b_get_retry 3 delay_before_retry 3 conn ect_port 802. BACKUP 服务器同上配置，先安装Ivs 再按装 keepalived,仍后配置 /etc/keepalived/keepalived.conf，只需将红色标示的部分改一下即可3. vi /etc/rcocal#/usr/local/sbin/lvs-dr.sh 将 Ivs-dr.sh 这个脚本注释掉。步#/usr/local/sbin/lvs-dr.sh stop 停止 lvs-dr 脚本#/etc/init.d/keepalived start启动 keepalived 服务，keepalived 就能利用 keepalived.conf 配己置文件，实现负载均衡和高可用.4. 查看lvs服务是否正常#watch ipvsadm -nIP Virtual Server ver