Linux下负载均衡软件LVS配置(VS/DR)教程

VS/DR： 即（Virtual Server via Direct Routing）
 
也就是用直接路由技术实现虚拟服务器。它的连接调度和管理与VS/NAT和VS/TUN中的一样，但它的报文转发方法又有不同，VS/DR通过改写请求报文的MAC地址，将请求发送到Real Server，而Real Server将响应直接返回给客户，免去了VS/TUN中的IP隧道开销。这种方式是三种负载调度机制中性能最高最好的，但是必须要求Director Server与Real Server都有一块网卡连在同一物理网段上。

例子

DIP:172.28.95.220
VIP:172.28.95.245
RIP:172.28.95.221(222)

负载调度器:

[root@LVS-GS001 ipvsadm-1.24]# ifconfig eth1:1 172.28.95.245 netmask 255.255.255.0 up
[root@LVS-GS001 ipvsadm-1.24]# ifconfig
eth1      Link encap:Ethernet  HWaddr 00:15:5D:C7:83:7D 
          inet addr:172.28.95.220  Bcast:172.28.95.255  Mask:255.255.240.0
eth1:1    Link encap:Ethernet  HWaddr 00:15:5D:C7:83:7D 
          inet addr:172.28.95.245  Bcast:172.28.95.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Interrupt:9 Base address:0xc000
[root@LVS-GS001 ipvsadm-1.24]# ipvsadm
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
[root@LVS-GS001 ipvsadm-1.24]# ipvsadm --help
[root@LVS-GS001 ipvsadm-1.24]# ipvsadm --set 30 5 60    #--set tcp tcpfin udp        set connection timeout values
[root@LVS-GS001 ipvsadm-1.24]# ipvsadm -A -t 172.28.95.245:80 -s wrr -p 20    #-A        add virtual service with options    #-s scheduler         one of rr|wrr|lc|wlc|lblc|lblcr|dh|sh|sed|nq,the default scheduler is wlc.
[root@LVS-GS001 ipvsadm-1.24]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  172.28.95.245:80 wrr persistent 20
[root@LVS-GS001 ipvsadm-1.24]# ipvsadm -a -t 172.28.95.245:80 -r 172.28.95.221:80 -g -w 1 
[root@LVS-GS001 ipvsadm-1.24]# ipvsadm -a -t 172.28.95.245:80 -r 172.28.95.222:80 -g -w 1
[root@LVS-GS001 ipvsadm-1.24]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  172.28.95.245:80 wrr persistent 20
  -> 172.28.95.222:80             Route   1      0          0        
  -> 172.28.95.221:80             Route   1      0          0
Real-Server:

[root@RealServer001 ~]# ifconfig lo:221 172.28.95.245:80 netmask 255.255.255.255 up           
[root@RealServer001 ~]# echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore
[root@RealServer001 ~]# echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce
[root@RealServer001 ~]# echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
[root@RealServer001 ~]# echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce