LVS+Keepalived实现高可用集群 操作系统平台：CentOS5.2 软件：LVS+keepalived
LVS+Keepalived 介绍 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）； 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
IP配置信息: 1. LVS-DR-Master 192.168.2.166 2. LVS-DR-BACKUP 192.168.2.167 3. LVS-DR-VIP 192.168.2.170 4. WEB1-Realserver 192.168.2.171 5. WEB2-Realserver 192.168.2.172 6. GateWay 192.168.2.253 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 1. #lsmod |grep ip_vs 2. #uname -r 3. 2.6.18-53.el5PAE 4. #ln -s /usr/src/kernels/2.6.18-53.el5PAE-i686/ /usr/src/linux 5. 6. #tar zxvf ipvsadm-1.24.tar.gz 7. #cd ipvsadm-1.24 8. #make && make install 9. #find / -name ipvsadm # 查看ipvsadm的位置 10. 11. #tar zxvf keepalived-1.1.15.tar.gz 12. #cd keepalived-1.1.15 13. #./configure && make && make install 14. #find / -name keepalived # 查看keepalived位置 15. 16. #cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/ 17. #cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/ 18. #mkdir /etc/keepalived 19. #cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/ 20. #cp /usr/local/sbin/keepalived /usr/sbin/ 21. #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=192.168.2.253 # website director vip. WEB_VIP=192.168.2.170 WEB_RIP1=192.168.2.171
WEB_RIP2=192.168.2.172 . /etc/rc.d/init.d/functions logger $0 called with $1 case \"$1\" in start) # Clear all iptables rules. /sbin/iptables -F # Reset iptables counters. /sbin/iptables -Z # Clear all ipvsadm rules/services. /sbin/ipvsadm -C #set lvs vip for dr /sbin/ipvsadm --set 30 5 60 /sbin/ifconfig eth0:0 $WEB_VIP broadcast $WEB_VIP netmask 255.255.255.255 up /sbin/route add -host $WEB_VIP dev eth0:0 /sbin/ipvsadm -A -t $WEB_VIP:80 -s wrr -p 3 /sbin/ipvsadm -a -t $WEB_VIP:80 -r $WEB_RIP1:80 -g -w 1 /sbin/ipvsadm -a -t $WEB_VIP:80 -r $WEB_RIP2:80 -g -w 1 touch /var/lock/subsys/ipvsadm >/dev/null 2>&1 # set Arp /sbin/arping -I eth0 -c 5 -s $WEB_VIP $GW >/dev/null 2>&1 ;; stop) /sbin/ipvsadm -C /sbin/ipvsadm -Z ifconfig eth0:0 down route del $WEB_VIP >/dev/null 2>&1 rm -rf /var/lock/subsys/ipvsadm >/dev/null 2>&1 /sbin/arping -I eth0 -c 5 -s $WEB_VIP $GW echo \"ipvsadm stoped\" ;; status) if [ ! -e /var/lock/subsys/ipvsadm ];then echo \"ipvsadm is stoped\" exit 1
else ipvsadm -ln echo \"..........ipvsadm is OK.\" fi ;; *) echo \"Usage: $0 {start|stop|status}\" exit 1 esac exit 0 2． 配置Realserver脚本.
#!/bin/bash # Written by NetSeek # description: Config realserver lo and apply noarp WEB_VIP=192.168.2.170 . /etc/rc.d/init.d/functions case \"$1\" in start) ifconfig lo:0 $WEB_VIP netmask 255.255.255.255 broadcast $WEB_VIP /sbin/route add -host $WEB_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 $WEB_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\" ;;
status) # Status of LVS-DR real server. islothere=`/sbin/ifconfig lo:0 | grep $WEB_VIP` isrothere=`netstat -rn | grep \"lo:0\" | grep $web_VIP` if [ ! \"$islothere\" -o ! \"isrothere\" ];then # Either the route or the lo:0 device # not found. echo \"LVS-DR real server Stopped.\" else echo \"LVS-DR Running.\" fi ;; *) # Invalid entry. echo \"$0: Usage: $0 {start|status|stop}\" exit 1 ;; esac exit 0
附上realserver机上的/etc/sysctl.conf：
# Kernel sysctl configuration file for Red Hat Linux # # For binary values, 0 is disabled, 1 is enabled. See sysctl(8) and # sysctl.conf(5) for more details. # Controls IP packet forwarding net.ipv4.ip_forward = 1 # Controls source route verification net.ipv4.conf.default.rp_filter = 1 # Do not accept source routing net.ipv4.conf.default.accept_source_route = 0 # Controls the System Request debugging functionality of the kernel kernel.sysrq = 0 # Controls whether core dumps will append the PID to the core filename. # Useful for debugging multi-threaded applications. kernel.core_uses_pid = 1 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 或者采用secondary ip address方式配置 # vi /etc/sysctl.conf
添加以下内容如上所示：
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 (主调度器) ! Configuration File for keepalived global_defs { notification_email { acassen@firewall.loc failover@firewall.loc sysadmin@firewall.loc } notification_email_from Alexandre.Cassen@firewall.loc smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id LVS_DEVEL } vrrp_instance VI_1 { state MASTER
interface eth0 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.2.170 } } virtual_server 192.168.2.170 80 { delay_loop 6 lb_algo wrr lb_kind DR persistence_timeout 60 protocol TCP real_server 192.168.2.171 80 { weight 3 TCP_CHECK { connect_timeout 10 nb_get_retry 3 delay_before_retry 3 connect_port 80 } } real_server 192.168.2.172 80 { weight 3 TCP_CHECK { connect_timeout 10 nb_get_retry 3 delay_before_retry 3 connect_port 80 } } }
在备用调度器上： #vi /etc/keepalived/keepalived.conf (备用调度器) ! Configuration File for keepalived global_defs { notification_email { acassen@firewall.loc failover@firewall.loc sysadmin@firewall.loc } notification_email_from Alexandre.Cassen@firewall.loc smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id LVS_DEVEL } vrrp_instance VI_1 { state BACKUP interface eth0 virtual_router_id 51 priority 99 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.2.170 } } virtual_server 192.168.2.170 80 { delay_loop 6 lb_algo wrr lb_kind DR persistence_timeout 60 protocol TCP real_server 192.168.2.171 80 {
weight 3 TCP_CHECK { connect_timeout 10 nb_get_retry 3 delay_before_retry 3 connect_port 80 } } real_server 192.168.2.172 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。 #/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 LocalAddressort Scheduler Flags
-> RemoteAddressort 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 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效。
5．停Master服务器的keepalived服务，查看BAKCUP服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 http://www.linuxtone.org/viewthread.php?tid=69 学习LVS的三种转发模式 http://www.linuxtone.org/viewthread.php?tid=77 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
Keepalived 相关参考资料。 http://www.keepalived.org/documentation.html 原文地址 http://blog.chinaunix.net/u/18630/showart_1889903.html
因篇幅问题不能全部显示，请点此查看更多更全内容