利用 LVS+Keepalived 实现高性能高可用负载均衡

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贡献于2014-02-14

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利用 LVS+Keepalived 实现高性能高可用负载均衡 作者:NetSeek 网站: http://www.linuxtone.org 日期:2008-10-27 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. 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); 八种调度算法(rr,wrr,lc,wlc,lblc,lblcr,dh,sh)。 2. 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 二. 网站负载均衡拓朴图 . IP信息列表: 名称 IP LVS-DR-Master 61.164.122.6 LVS-DR-BACKUP 61.164.122.7 LVS-DR-VIP 61.164.122.8 WEB1-Realserver 61.164.122.9 WEB2-Realserver 61.164.122.10 GateWay 61.164.122.1 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 #wget http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.24.tar.gz #wget http://www.keepalived.org/software/keepalived-1.1.15.tar.gz 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 #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 #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/sbin/lvs-dr.sh #!/bin/bash # description: start LVS of DirectorServer #Written by :NetSeek http://www.linuxtone.org GW=61.164.122.1 # website director vip. SNS_VIP=61.164.122.8 SNS_RIP1=61.164.122.9 SNS_RIP2=61.164.122.10 ./etc/rc.d/init.d/functions 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 255.255.255.255 broadcast $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 -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 ifconfig eth0:1 down route del $SNS_VIP route del $SS_VIP rm -rf /var/lock/subsys/ipvsadm >/dev/null 2>&1 echo "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 2. 配置 Realserver 脚本. #vi /usr/local/sbin/realserver.sh #!/bin/bash # description: Config realserver lo and apply noarp #Written by :NetSeek http://www.linuxtone.org SNS_VIP=61.164.122.8 . /etc/rc.d/init.d/functions case "$1" in start) ifconfig lo:0 $SNS_VIP netmask 255.255.255.255 broadcast $SNS_VIP /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) 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/all/arp_announce echo "RealServer Stoped" ;; *) echo "Usage: $0 {start|stop}" exit 1 esac exit 0 或者采用 secondary ip address 方式配置 # vi /etc/sysctl.conf net.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 #sysctl –p #ip addr add 61.164.122.8/32 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 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 { cnseek@gmail.com # failover@firewall.loc # sysadmin@firewall.loc } notification_email_from sns-lvs@gmail.com smtp_server 127.0.0.1 # smtp_connect_timeout 30 router_id LVS_DEVEL } # 20081013 written by :netseek # VIP1 vrrp_instance VI_1 { state MASTER #备份服务器上将 MASTER 改为 BACKUP interface eth0 virtual_router_id 51 priority 100 # 备份服务上将 100 改为 99 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 61.164.122.8 #(如果有多个 VIP,继续换行填写.) } } virtual_server 61.164.122.8 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 61.164.122.9 80 { weight 3 #(权重) TCP_CHECK { connect_timeout 10 #(10秒无响应超时) nb_get_retry 3 delay_before_retry 3 connect_port 80 } } real_server 61.164.122.10 80 { weight 3 TCP_CHECK { connect_timeout 10 nb_get_retry 3 delay_before_retry 3 connect_port 80 } } } 2. BACKUP 服务器同上配置,先安装 lvs 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/rc.local #/usr/local/sbin/lvs-dr.sh 将 lvs-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 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 –ln IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 61.164.122.8:80 wrr persistent 60 -> 61.164.122.10:80 Route 3 0 0 -> 61.164.122.9:80 Route 3 0 0 #tail –f /var/log/message 监听日志,查看状态。 5.停 Master 服务器的 keepalived 服务,查看 BAKCUP 服务器是否能正常接管. 四.相关参考 1.LVS 基础知识汇总 ¾ LVS的算法介绍 http://www.linuxtone.org/viewthread.php?tid=69 ¾ 学习LVS的三种转发模式 http://www.linuxtone.org/viewthread.php?tid=77 ¾ LVS中的IP负载均衡技术 http://www.linuxtone.org/viewthread.php?tid=68 更多的请到http://www.linuxtone.org 负载均衡版查看 3. Keepalived 相关参考资料。 http://www.keepalived.org/documentation.html

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