前言* 随着互联网的发展，提供用户访问的web服务器，必须要保证每天24不间断服务，访问量不断增加，有什么好的web架构既能实现高可用性负载均衡，而且价格又是免费的呢？答案有木有？有！lvs+keepalived 是不错的选择！
一、实验环境：4台centos 5.4 ，以及简单的拓扑图： LVS-Master 192.168.2.108 LVS-BACKUP 192.168.2.109 LVS-DR-VIP 192.168.2.100 WEB1-Realserver192.168.2.79 WEB2-Realserver 192.168.2.80 二、安装ipvsadm+keepalived,用脚本自动安装： 由于我们使用的是lvs+keepalived，所以这里不需要配置lvs-dr脚本，直接在keepalived.conf里面配置即可！ #!/bin/sh ###脚本编写目的:自动安装lvs+keepalived ###编写时间: 7月6日17:25:39 ###初稿人:wugk ###定义变量 DIR1=/usr/src DIR2=/usr/local cat << EOF ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++Welcome to use Linux installed a key LVS+KEEPALIVED shells scripts +++++++++++++++++++++*************************++++++++++++++++++++++++ EOF if [ $UID -ne 0 ];then echo “This script must use root user ,please exit……” sleep 2 exit 0 fi download () { cd $DIR1 && wget -c /software/kernel-2.6/ipvsadm-1.24.tar.gz /software/keepalived-1.1.15.tar.gz if [ $? = 0 ];then echo "Download LVS Code is OK!" else echo "Download LVS Code is failed,Please check!" exit 1 fi } ipvsadm_install () { ln -s $DIR1/kernels/2.6.* $DIR1/linux cd $DIR1 && tar xzvf ipvsadm-1.24.tar.gz &&cd ipvsadm-1.24 && make && make install if [ $? -eq 0 ];then echo "Install ipvsadm success,please waiting install keepalived ..............." else echo "Install ipvsadm failed ,please check !" exit 1 fi } keepalived_install () { cd $DIR1 && tar -xzvf keepalived-1.1.15.tar.gz &&cd keepalived-1.1.15 && ./configure && make && make install if [ $? -eq 0 ];then echo "Install keepalived success,please waiting configure keepalived ..............." else echo "Install keepalived failed ,please check install version !" exit 1 fi } ######如果以上软件包编译报错的话，请检查相关的版本跟系统版本之间的关系，然后手动下载安装. keepalived_config () { cp $DIR2/etc/rc.d/init.d/keepalived/etc/rc.d/init.d/ && cp $DIR2/etc/sysconfig/keepalived /etc/sysconfig/ && mkdir -p /etc/keepalived &&cp $DIR2/etc/keepalived/keepalived.conf /etc/keepalived/ && cp $DIR2/sbin/keepalived /usr/sbin/ if [ $? -eq 0 ];then echo "Keepalived system server config success!" else echo "Keepalived system server config failed ,please check keepalived!" exit 1 fi } PS3="Please select Install Linux Packages:" select option in download ipvsadm_install keepalived_install keepalived_config do $option done 以上脚本分别在lvs-master和lvs-backup上执行安装。 三、配置keepalived.conf：内容如下是lvs-master配置 也可以参考配置：/download/keepalived.conf 可以直接打开 ! Configuration File for keepalived global_defs { notification_email {wgkgood@ } notification_email_from wgkgood@ smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id LVS_DEVEL } # VIP1 vrrp_instance VI_1 { state MASTER interface eth0 lvs_sync_daemon_inteface eth0 virtual_router_id 51 priority 100 advert_int 5 authentication {auth_type PASS auth_pass 1111 } virtual_ipaddress {192.168.2.100 } } #REAL_SERVER_1 virtual_server 192.168.2.100 80 { delay_loop 6 lb_algo wlc lb_kind DR persistence_timeout 60 protocol TCP real_server 192.168.2.79 80 {weight 100 TCP_CHECK {connect_timeout 10 nb_get_retry 3 delay_before_retry 3 connect_port 80 } } #REAL_SERVER_2 real_server 192.168.2.80 80 {weight 100 TCP_CHECK {connect_timeout 10 nb_get_retry 3 delay_before_retry 3 connect_port 80 } } } 注意***Lvs-backup端同样配置，只需要更改state MASTER为state BACKUP，修改priority 100为priority 90即可。 四、分别在web1、web2上配置好apache，然后分别执行如下脚本： 如下的VIP1指的是lvs-dr-vip地址，及对外提供访问的虚拟ip： #!/bin/sh PS3="Please Choose whether or not to start a realserver VIP1 configuration:" select i in "start" "stop" do case "$i" in start) read -p"Please enter the virtual server IP address:" VIP1 ifconfig lo:0 $VIP1 netmask 255.255.255.255 broadcast $VIP1 /sbin/route add -host $VIP1 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" exit 0 ;; stop) ifconfig lo:0 down route del $VIP1 >/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" exit 1 ;; *) echo "Usage: $0 {start|stop}" exit 2 esac done 脚本会提示是否启动，按1即启动，然后输入vip地址 192.168.2.100 ，用ifconfig你会看到：lo:0的ip即表示配置ip成功。 lo:0Link encap:Local Loopback inet addr:192.168.2.100Mask:255.255.255.255 UP LOOPBACK RUNNINGMTU:16436Metric:1 五、最后启动lvs-master、lvs-backup上面的keepalived服务即可： /etc/init.d/keepalived restart 查看lvs-master日志： 在浏览器里面访问 http://192.168.2.100/ 即可！当你宕掉lvs-master后，lvs-backup会接管变成lvs-master提供服务，当lvs-master故障恢复后，lvs-backup又会变成原来的状态！ 所安装的脚本可以在这里下载： /download/lvs-keepalived.sh 在lvs-master和lvs-backup上执行 /download/realserver.sh 在web服务器端执行
