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


  1. LVS-DR-Master        61.164.122.6        

  2. LVS-DR-BACKUP        61.164.122.7        

  3. LVS-DR-VIP        61.164.122.8        

  4. WEB1-Realserver        61.164.122.9        

  5. WEB2-Realserver        61.164.122.10        

  6. GateWay        61.164.122.1   

安装LVS和Keepalvied软件包
下载相关软件包

  1.      #mkdir /usr/local/src/lvs

  2.      #cd /usr/local/src/lvs

  3.      #wget http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.24.tar.gz

  4.      #wgethttp://www.keepalived.org/software/keepalived-1.1.15.tar.gz


 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


  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


  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               


  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.


 配置LVS实现负载均衡
  vi /etc/sysctl.conf

  1.           net.ipv4.conf.lo.arp_ignore = 1

  2.           net.ipv4.conf.lo.arp_announce = 2

  3.           net.ipv4.conf.all.arp_ignore = 1

  4.           net.ipv4.conf.all.arp_announce = 2

  5.           sysctl   -p

       ip addr add 61.164.122.8/32 dev lo

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

  1.   ! Configuration File for keepalived


  3. global_defs {

  4.    notification_email {

  5.          yakexi007@vip.qq.com

  6.    }

  7.    notification_email_from sns-lvs@gmail.com

  8.    smtp_server 127.0.0.1

  9.   # smtp_connect_timeout 30

  10.    router_id LVS_DEVEL

  11. }


  13. # 20081013 written by :netseek

  14. # VIP1

  15. vrrp_instance VI_1 {

  16.     state MASTER             #备份服务器上将MASTER改为BACKUP   

  17.     interface eth0

  18.     virtual_router_id 51

  19.     priority 100    # 备份服务上将100改为99

  20.     advert_int 1

  21.     authentication {

  22.         auth_type PASS

  23.         auth_pass 1111

  24.     }

  25.     virtual_ipaddress {

  26.         61.164.122.8   

  27.         #(如果有多个VIP，继续换行填写.)

  28.     }

  29. }


  31. virtual_server 61.164.122.8 80 {

  32.     delay_loop 6                  #(每隔10秒查询realserver状态)

  33.     lb_algo wrr                  #(lvs 算法)

  34.     lb_kind DR                  #(Direct Route)

  35.     persistence_timeout 60        #(同一IP的连接60秒内被分配到同一台realserver)

  36.     protocol TCP                #(用TCP协议检查realserver状态)


  38.     real_server 61.164.122.9 80 {

  39.         weight 3               #(权重)

  40.         TCP_CHECK {

  41.         connect_timeout 10       #(10秒无响应超时)

  42.         nb_get_retry 3

  43.         delay_before_retry 3

  44.         connect_port 80

  45.         }

  46.     }

  47.     real_server 61.164.122.10 80 {

  48.         weight 3

  49.         TCP_CHECK {

  50.         connect_timeout 10

  51.         nb_get_retry 3

  52.         delay_before_retry 3

  53.         connect_port 80

  54.         }

  55.      }

  56. }

#/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.
     整个LVS负均衡HA方案，由keepalived.conf一个文件即可搞定！