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:

LVS-DR-Master          192.168.2.166 LVS-DR-BACKUP          192.168.2.167 LVS-DR-VIP             192.168.2.170         WEB1-Realserver        192.168.2.171 WEB2-Realserver        192.168.2.172 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 #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=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