LB 服务器负载均衡【旁路部署】

LB旁路部署案例
一、 需求

• 为了实现服务器对外网用户提供服务的可靠性，客户在现网中部署了LB设备，LB采用旁路方式部署，要求外网主机访问时的流量经过LB轮询到内部服务器，一台服务器down机不影响其正常业务。
  二、 拓扑环境
  
  三、 配置思路
• 配置各个设备ip地址及路由，保证ip可达
• 配置检测模板
• 配置ip地址池
• 配置实服务组，调用检测模板和ip地址池
• 配置实服务，关联实服务组
• 配置虚服务器，关联实服务组
• 测试
  四、 配置步骤
  配置脚本如下所示：
  出口NAT设备配置：

  sysname NAT#system-working-mode standardxbar load-singlepassword-recovery enablelpu-type f-series#vlan 1#interface Serial1/0#interface Serial2/0#interface Serial3/0#interface Serial4/0#interface NULL0#interface GigabitEthernet0/0port link-mode routecombo enable copperip address 192.168.34.4 255.255.255.0#interface GigabitEthernet0/1port link-mode routecombo enable copperip address 100.1.46.4 255.255.255.0nat outboundnat server protocol tcp global 100.1.46.4 2323 inside 192.168.35.5 2323#interface GigabitEthernet0/2port link-mode routecombo enable copper#interface GigabitEthernet5/0port link-mode routecombo enable copper#interface GigabitEthernet5/1port link-mode routecombo enable copper#interface GigabitEthernet6/0port link-mode routecombo enable copper#interface GigabitEthernet6/1port link-mode routecombo enable copper#scheduler logfile size 16#line class auxuser-role network-operator#line class consoleuser-role network-admin#line class ttyuser-role network-operator#line class vtyuser-role network-operator#line aux 0user-role network-operator#line con 0user-role network-admin#line vty 0 63user-role network-operator#ip route-static 0.0.0.0 0 100.1.46.6ip route-static 192.168.1.0 24 192.168.34.3ip route-static 192.168.2.0 24 192.168.34.3ip route-static 192.168.35.0 24 192.168.34.3#domain system#domain default enable system#role name level-0description Predefined level-0 role#role name level-1description Predefined level-1 role#role name level-2description Predefined level-2 role#role name level-3description Predefined level-3 role#role name level-4description Predefined level-4 role#role name level-5description Predefined level-5 role#role name level-6description Predefined level-6 role#role name level-7description Predefined level-7 role#role name level-8description Predefined level-8 role#role name level-9description Predefined level-9 role#              role name level-10description Predefined level-10 role#role name level-11description Predefined level-11 role#role name level-12description Predefined level-12 role#role name level-13description Predefined level-13 role#role name level-14description Predefined level-14 role#user-group system

LB关键配置：

interface GigabitEthernet1/0/1 port link-mode route combo enable copper ip address 192.168.0.1 255.255.255.0#interface GigabitEthernet1/0/2 port link-mode route combo enable copper ip address 192.168.35.5 255.255.255.0loadbalance snat-pool pool ip range start 192.168.35.5 end 192.168.35.5#server-farm sf snat-pool pool probe t1#real-server rs1 ip address 192.168.1.1 port 23 weight 150 server-farm sf#real-server rs2 ip address 192.168.2.2 port 23 weight 120     server-farm sf#virtual-server vs type tcp port 2323  virtual ip address 192.168.35.5 default server-farm sf service enable # ip route-static 0.0.0.0 0 192.168.35.3#acl basic 2000 rule 0 permitsecurity-zone name Trust import interface GigabitEthernet1/0/2#security-zone name DMZ#security-zone name Untrust#security-zone name Management#zone-pair security source Any destination Any packet-filter 2000#return

五、 测试
外网主机telnet外网映射到LB的地址和端口，看是否可以访问到内部服务器
telnet 100.1.46.4 2323
Trying 100.1.46.4 ...
Press CTRL+K to abort
Connected to 100.1.46.4 ...

dis ip int brief
*down: administratively down
(s): spoofing (l): loopback
Interface Physical Protocol IP Address Description
GE0/0 down down -- --
GE0/1 up up 192.168.1.1 --
测试后可以正常访问到服务器A

退出登录后再尝试登录下，测试看是否可以轮询到另一个服务器
quit

The connection was closed by the remote host!
telnet 100.1.46.4 2323
Trying 100.1.46.4 ...
Press CTRL+K to abort
Connected to 100.1.46.4 ...

dis ip int brief
*down: administratively down
(s): spoofing (l): loopback
Interface Physical Protocol IP Address Description
GE0/0 up up 192.168.2.2 --

LB>dis real-server statistics
Slot 1:
Real server: rs1
Total connections: 7
Active connections: 0
Max connections: 1
Connections per second: 0
Max connections per second: 1
Server input: 13601 bytes
Server output: 15872 bytes
Throughput: 0 bytes/s
Inbound throughput: 0 bytes/s
Outbound throughput: 0 bytes/s
Max throughput: 3612 bytes/s
Max inbound throughput: 1359 bytes/s
Max outbound throughput: 2253 bytes/s
Received packets: 252
Sent packets: 238
Dropped packets: 0
Received requests: 0
Dropped requests: 0
Sent responses: 0
Dropped responses: 0
Connection failures: 0

Real server: rs2
Total connections: 8
Active connections: 1
Max connections: 1
Connections per second: 0
Max connections per second: 1
Server input: 15552 bytes
Server output: 17213 bytes
Throughput: 0 bytes/s
Inbound throughput: 0 bytes/s
Outbound throughput: 0 bytes/s
Max throughput: 5796 bytes/s
Max inbound throughput: 2451 bytes/s
Max outbound throughput: 3345 bytes/s
Received packets: 288
Sent packets: 264
Dropped packets: 0
Received requests: 0
Dropped requests: 0
Sent responses: 0
Dropped responses: 0
Connection failures: 0

dis virtual-server statistics
Slot 1:
Virtual server: vs
Total connections: 15
Active connections: 1
Max connections: 2
Connections per second: 0
Max connections per second: 1
Client input: 29257 bytes
Client output: 33165 bytes
Throughput: 0 bytes/s
Inbound throughput: 0 bytes/s
Outbound throughput: 0 bytes/s
Max throughput: 5796 bytes/s
Max inbound throughput: 2451 bytes/s
Max outbound throughput: 3345 bytes/s
Received packets: 542
Sent packets: 504
Dropped packets: 0
六、 注意事项

• 该拓扑图中，如果只是单纯配置服务器负载均衡，不针对外网进来的源做snat的话，是无法访问到服务器的，原因是，外网终端向LB发起访问，但是数据包回复时却是内网服务器直接给予的回应，服务器回包时，数据包到核心设备，直接按照缺省路由去做转发了，即使客户端收到数据包，由于发起和回应的地址不一致，则会认为数据包不是自己想要的，会直接丢弃
• 配置LB时，新建实服务，关联实服务组，最后在虚服务器下做关联时，设备会根据检测模板去轮询看是否和服务器可达，如果可达，将处于active状态，如果检测不可达，处于Probe-failed