linux下的LVS-DR模式

2021-10-23 03:28:06

DIP：调度器的IP地址

RIP：后台真实服务器(realserver)的IP地址

VIP：就是用于服务提供的虚拟IP

LVS的DR模式比较其NAT模式复杂，也不容易实现，因为这种模式更接近与基于硬件的负载均衡，虽然性能较硬件的负载均衡调度还有差距，但是与NAT和TUN模式性能有了较大的提高，其要求调度器和realserver在同一个网段内（可以使用交换机相连，当然也可以基于IP的网络连接），在这里调度器上仅仅使用一张网卡即可，DIP是否等于VIP都可以，DT模式最大的优势在于对服务质量的大幅提高，同时应采取相关的设置对realserver上ARP做的某些限制。

具体实现过程可以这么来说：

1、客户端发来请求报文到调度器，调度器接到分包不做深入的处理，仅仅把目标MAC地址根据算法修改成realserver pool里的某台真实服务器的MAC地址，同时在缓存一份连接记录（确保此次连接的所有报文都传到同一台realserver上）

2、Realserver接到报文，根据要求做相关的处理，处理结束之后，根据自身网卡绑定的VIP地址，改写报文的源、目标地址，直接把报文回复给客户端，而不再经过调度器，在客观上减轻了调度器的负担。

实验的平台三台VM下linux服务器主机（CentOS 7.5，内核是3.6版本的是默认支持LVS的，所以不需要重新编译内核，可以直接使用），其中一台用作调度器，另外两台用作realserver。

第一：在调度器上的设置：

[root@localhost ~]# yum -y install ipvsadm   //安装LVS管理工具
[root@localhost ~]# ifconfig    //查看初始的网卡信息（这里仅仅采用一张网卡）
eth0      Link encap:Ethernet  HWaddr 00:0C:29:09:22:5D  
          inet addr:192.168.1.196  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fe09:225d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:17657 errors:0 dropped:0 overruns:0 frame:0
          TX packets:17945 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:7404853 (7.0 MiB)  TX bytes:10817894 (10.3 MiB)
          Interrupt:169 Base address:0x2000 
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:88 errors:0 dropped:0 overruns:0 frame:0
          TX packets:88 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:6797 (6.6 KiB)  TX bytes:6797 (6.6 KiB)
[root@localhost ~]# vi /etc/init.d/lvsdr   //编写集群管理脚本，当然你也可以自己逐条添加
#!/bin/bash
#description:start LVS of Directorserver DR
VIP=192.168.1.200
RIP1=192.168.1.193
RIP2=192.168.1.195


#./etc/rc.d/init.d/functions
case "$1" in
        start)
        echo "start LVS of DirectorServer DR"
        /sbin/ifconfig eth0:0 $VIP broadcast $VIP netmask 255.255.255.255 up
        /sbin/route add -host $VIP dev eth0:0
        echo "1">/proc/sys/net/ipv4/ip_forward
        /sbin/ipvadm -C
        /sbin/ipvsadm -A -t $VIP:80 -s rr           //仍然是轮度算法
        /sbin/ipvsadm -a -t $VIP:80 -r $RIP1 –g     //-g表示采用直接路由模式
        /sbin/ipvsadm -a -t $VIP:80 -r $RIP2 -g
        /sbin/ipvsadm
        ;;
        stop)
        echo "stop LVS of DirectorServer DR"
        echo "0" >/proc/sys/net/ipv4/ip_forward
        /sbin/ipvsadm -C
        /sbin/ifconfig eth0:0 down
        ;;
        *)
        echo "Usage:$0{start|stop}"
        exit 1
 esac
[root@localhost ~]# chmod a+x /etc/init.d/lvsndr   //加可执行权限
[root@localhost ~]# /etc/init.d/lvsdr start
start LVS of DirectorServer DR
/etc/init.d/lvsdr: line 13: /sbin/ipvadm: No such file or directory
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.1.200:http rr
  -> 192.168.1.195:http           Route   1      0          0         
  -> 192.168.1.193:http           Route   1      0          0    
[root@localhost ~]# ifconfig   //查看变化信息
eth0      Link encap:Ethernet  HWaddr 00:0C:29:09:22:5D  
          inet addr:192.168.1.196  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fe09:225d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:18342 errors:0 dropped:0 overruns:0 frame:0
          TX packets:18549 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:7480550 (7.1 MiB)  TX bytes:10886441 (10.3 MiB)
          Interrupt:169 Base address:0x2000 
eth0:0    Link encap:Ethernet  HWaddr 00:0C:29:09:22:5D  
          inet addr:192.168.1.200  Bcast:192.168.1.200  Mask:255.255.255.255
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Interrupt:169 Base address:0x2000 
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:88 errors:0 dropped:0 overruns:0 frame:0
          TX packets:88 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:6797 (6.6 KiB)  TX bytes:6797 (6.6 KiB)

第二：在节点上的设置（由于在两个节点上的设置基本完全相同，故这里只设置节点之一）

在192.168.1.193上

[root@localhost ~]# ifconfig   //查看网卡信息
eth0      Link encap:Ethernet  HWaddr 00:0C:29:B7:97:5B  
          inet addr:192.168.1.193  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:feb7:975b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:48655 errors:0 dropped:0 overruns:0 frame:0
          TX packets:39793 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:16204310 (15.4 MiB)  TX bytes:6641366 (6.3 MiB)
          Interrupt:169 Base address:0x2000 
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:12600 errors:0 dropped:0 overruns:0 frame:0
          TX packets:12600 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:8047060 (7.6 MiB)  TX bytes:8047060 (7.6 MiB)
[root@localhost ~]# vi /etc/init.d/lvscdr    //编写ARP及VIP绑定脚本（两节点完全相同）
#!/bin/bash
#descrpption :start realserver DR
VIP=192.168.1.200
#./etc/rc.d/init.d/functions
case "$1" in
        start)
        echo "start LVS of RealServer DR"
        /sbin/ifconfig lo:0 $VIP broadcast $VIP netmask 255.255.255.255 up
        /sbin/route add -host $VIP dev lo:0
        echo "1">/proc/sys/net/ipv4/conf/lo/arp_ignore
        echo "2">/proc/sys/net/ipv4/conf/all/arp_announce
        echo "1">/proc/sys/net/ipv4/conf/all/arp_ignore
        echo "2">/proc/sys/net/ipv4/conf/all/arp_announce
        ;;
        stop)
        /sbin/ifconfig lo:0 down
        echo "0">/proc/sys/net/ipv4/conf/lo/arp_ignore
        echo "0">/proc/sys/net/ipv4/conf/all/arp_announce
        echo "0">/proc/sys/net/ipv4/conf/all/arp_ignore
        echo "0">/proc/sys/net/ipv4/conf/all/arp_announce
        ;;
        *)
        echo "Usage:$0 {start|stop}"
        exit 1
esac
[root@localhost ~]# chmod a+x /etc/init.d/lvscdr 
[root@localhost ~]# /etc/init.d/lvscdr start
[root@localhost ~]# ifconfig   //查看变化信息
eth0      Link encap:Ethernet  HWaddr 00:0C:29:B7:97:5B  
          inet addr:192.168.1.193  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:feb7:975b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:48853 errors:0 dropped:0 overruns:0 frame:0
          TX packets:39954 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:16225588 (15.4 MiB)  TX bytes:6659428 (6.3 MiB)
          Interrupt:169 Base address:0x2000 
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:12600 errors:0 dropped:0 overruns:0"frale:0
   $(     TX packets:12600 erpors*0 dropped:8 oferruns:0 carrier:0
          collishons:0 tXqueuelen:0 
     0 `  RX bytes:8047060 (7.6 MiB)  VX bytes:8047060 (7.6 MiB)
ìo:0"     Link encap:Local LoopbacK  
      !   ijet addr:192.16:.1.200  Mcsk:2%5.255.055.255
       `  UP LOOPBACK RUN 
ING  MTU*1643¶  Metric:1

第三测试的部分：

为了测试效果明显，所以在rea,server特意设罦网页的䆅容不同，当然这仅仅是为了测试用，在真实的环境中是必须保持网顴内容的完兩相尌的　

测试效果

在地址栏釈输入VIP测诅,并临不断的列新页面

linux下的LVS-DR模式

M在调约器上观看

[root@localhost ~] (ipvsaɤ聭
Iࡐ Virtual œerѶer versio࡮ 1®2.9 (ѳize=4096) Prot耠LocalAddress:Port0Schedul%r цlags
  -耾ࠠRemoteAddr%ss:ѐort   Ƞ       Forward Weight ActiveConn InActConn
TCP  192.168.1.200:http rr
  -> 192.168.1.195:http           Route   1      0          5         
  -> 192.168.1.193:http           Route   1      0          4         
[root@localhost ~]# ipvsadm -lnc
IPVS connection entries
pro expire state       source             virtual            destination
TCP 01:51  FIN_WAIT    192.168.1.188:53751 192.168.1.200:80   192.168.1.193:80
TCP 01:53  FIN_WAIT    192.168.1.188:53760 192.168.1.200:80   192.168.1.195:80
TCP 01:52  FIN_WAIT    192.168.1.188:53755 192.168.1.200:80   192.168.1.193:80
TCP 01:53  FIN_WAIT    192.168.1.188:53756 192.168.1.200:80   192.168.1.195:80
TCP 00:46  FIN_WAIT    192.168.1.188:53746 192.168.1.200:80   192.168.1.195:80
TCP 01:53  FIN_WAIT    192.168.1.188:53759 192.168.1.200:80   192.168.1.193:80
TCP 01:53  FIN_WAIT    192.168.1.188:53757 192.168.1.200:80   192.168.1.193:80
TCP 01:52  FIN_WAIT    192.168.1.188:53754 192.168.1.200:80   192.168.1.195:80
TCP 01:53  FIN_WAIT    192.168.1.188:53758 192.168.1.200:80   192.168.1.195:80

linux下的LVS-DR模式

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