BIWEB开源PHP WMS系统创始人ArthurXF肖飞的blog

　　很多Linux的朋友也许都非常熟悉LVS负载均衡软件了，但是在FREEBSD下如何做负载均衡呢？
　　其实FREEBSD也有很多负载均衡的方法。本文由ArthurXF倾情奉献，谢谢支持！
　　负载均衡就是要把高流量合理的分配给不同的服务器，让每台服务器在最大承受能力范围内，最好的为用户服务。负载均衡其实就是如何把流量合理分配的工作。
　　当然负载均衡的办法很多，我ArthurXF这里只给出两个方法，以供大家学习参考。
1.构建流量控制防火墙（桥接模式）
概述
利用FreeBSD内核支持的BRIDGE、IPFIREWALL以及DUMMYNET选项，可以建立基于FreeBSD的透明流量控制防火墙（桥接模式），起到限制流量和包过滤的功能。









2.SG Cluster（一个简单实现集群的方法）
官方网址：http://turtle.ee.ncku.edu.tw/sgcluster/
SG Cluster是基于FREEBSD的NAT执行和SG软件分配建立的负载均衡工具。
具有如下特点：
易管理 - 有非常友好和简单安装的web用户管理界面。

图形化 - 系统将运行在不同系统上的集群后台服务高亮图形化显示在一个客户端。

可升级 - 系统负载能力可随着加入新的集群服务器而得到提升。

负载平衡 - 系统自动发送请求到最小负载的服务器上，以达到系统的最佳性能。

容错性 - SG负载均衡系统监控所有的服务器，仅仅将请求发送给有效的服务器，并可在整个负载均衡系统中设置多个负载均衡服务器，以避免系统中的单点故障。

高负载 - SG负载均衡可以标记系统中的过多冗余，系统还能在系统升级的时候维持正常服务。

配置
Config document from offical site..

http://turtle.ee.ncku.edu....

CONFIGURATION
edit system config files

There is an editor 'ee' bundled in SG system disk, you can use 'ee' to edit the configuration files under /etc

/etc/rc.conf.local

this file contains hostname information, see below for example

1 hostname="ds211.ee.ncku.edu.tw" # Set this!
2
3 gateway_enable="YES" # Set to YES if this host will be a gateway.
4 firewall_enable="YES" # firewall (see /etc/rc.firewall) or NO

line 1: set the hostname of the SG load balancer

/etc/ sg.conf

this file contains the configuration information of SG system, see below for example

1 # SG CLUSTER CONFIGURATION, CHANGE FOR YOUR NEED!!!
2
3 sgpath="/stand" # where sg related program is
4 temporary_ip="10.0.0.1" # ip before start sg
5 temporary_gw="10.0.0.253" # gateway before start sg
6
7 public_interface="fxp0"
8 private_interface="fxp1"
9
10 default_gw="140.116.72.253"
11
12 public_ip="140.116.72.136"
13 public_netmask="255.255.255.0"
14 private_ip="192.168.1.253"
15 private_netmask="255.255.255.0"
16
17 group_ip="140.116.72.137 140.116.72.138"
18
19 # map real servers to server group
20 natd_parameter="
21 -redirect_address 192.168.1.1 140.116.72.137
22 -redirect_address 192.168.1.2 140.116.72.137
23 -redirect_address 192.168.1.3 140.116.72.137
24 -redirect_port tcp 192.168.1.2:23 140.116.72.138:23
25 -redirect_port tcp 192.168.1.3:23 140.116.72.138:23
26 -redirect_port tcp 192.168.1.4:23 140.116.72.138:23
27 "
28
29 # username/passwd used by sgcmd to connect sgctrld
30 username="dslab"
31 password="dslab"
32
33 # init command sent to sgctrld
34 init_command="
35 set g 140.116.72.137:0 keyport_list 0
36 set g 140.116.72.137:0 s 192.168.1.1:0 weight 2
37 set g 140.116.72.137:0 s 192.168.1.2:0 weight 1
38 set g 140.116.72.137:0 s 192.168.1.3:0 weight 1
39 set g 140.116.72.138:23 keep_same_server 1
40 set g 140.116.72.138:23 keyport_list 0 23/tcp
41 set g 140.116.72.138:23 s 192.168.1.2:23 weight 1
42 set g 140.116.72.138:23 s 192.168.1.3:23 weight 1
43 set g 140.116.72.138:23 s 192.168.1.4:23 weight 2
44 "
45
46 # THERE SHOULD NO NEED TO CHANGE FROM BELOW ########################################
47
48 bidd_ip="234.5.6.7" # multicast group ip for bidd
49 bidd_port="3456" # port for bidd
50 bidd_master_heartbeat_interval="8"
51 bidd_master_timeout="10"
52 bidd_bid_timeout="3"
53 bidd_start_script="$sgpath/sgstart.sh"
54 bidd_stop_script="$sgpath/sgstop.sh"
55 bidd_continue_script="$sgpath/sgcontinue.sh"
56
57 sgmon_calc_status_interval="10"
58 sgmon_port_test_interval="60"
59 sgmon_host_timeout="2"
60
61 sgctrld_passwd_file="/etc/sgctrld.passwd"




line 7,8: set the name of public interface and private interface


Ethernet card supported by SG load balancer:

ed - NE2000, 3com 3C503 (ed0 port 0x300 irq10, ed1 port 0x320 irq11)
ie - 3com 30507, Intel Ether Express (ie0 port 0x280 irq5, ie1 port 0x340 irq 7)
de - DEC 21040/21140 based PCI card
fxp - Intel Ether Express pro
vr - DLink DFE530tx
xl - 3Com 3C900/3C905/3C905B


line 10: the default gateway for public interface

line 12-15: set the ip and netmask of the public interface and private interface

line 17: the ip of server groups (separated by space)

line 20-27: define servers in each server group

In this example, 2 server groups, 140.116.72.137:0 and 140.116.72.138:23, are defined, echo of them has 3 member server in the group.

line 30,31: the username/passwd used by web interface to login sgctrld

line 34-44: initial command sent to sgctrld to set SG properties,

property setting syntax:

set group [group_ip] [group_property] [value]
set group [group_ip] server [server_ip] [server_property] [value]

group property name description
name group name
active_flag 0=off, 1=on
keyport_list port list, 0 means icmp, NNN/udp=udp port, NNN/tcp=tcp port, where NNN=1..65535
select_method 0=roundrobin, 1=by_conn, 2=by_pkt, 3=by_clntip, 4=by_ext
keep_same_server  0=off, 1=on
failure_detect_by_packet_snoop 0=off, 1=on
recovery_detect_by_packet_snoop 0=off, 1=on
packet_delta_threshold pkt lost upper limit for each keyport
packet_timeout_threshold timeout upper limit for each keyport, unit:second
failure_detect_by_porttest 0=off, 1=on
recovery_detect_by_porttest 0=off, 1=on
porttest_error_threshold 0-65535
failure_detect_by_heartbeat 0=off, 1=on
recovery_detect_by_heartbeat 0=off, 1=on
heartbeat_timeout_threshold 0-65535
mcast_mode 0=deny, 1=bypass, 2=readwrite, 3=rdonly
multicast_addr multicast address for service program
mcast_error_threshold 0-65535
deny_interval deny interval for evil client  
connection_count_limit 1-65535, limit per client, 0 no limit
connection_rate_limit 1-65535, limit per client, 0 no limit
finwait_tcp_limit 1-65535, limit per client, 0 no limit

 server property name value
name server name
ac_list server access control list, ex: "140.116.72/24 !140.116.49.0/24"
weight 0-255
external_count a counter representing server load defined server program
status 0=dead, 1=pending, 2=alive

/etc/resolv.conf

set the dns server

/etc/hosts

local host table



set root password

use 'passwd root' to change root password of SG system



set sgctrld password

The password file of sgctrld is /etc/sgctrld.passwd, you can use

echo 'your_name:`makepwd your_passwd`'>;>;/etc/sgctrld.passwd

to add your_name/your_passwd to /etc/sgctrld.passwd

Or you can also 'ee' to edit the /etc/sgctrld.passwd directly to remove old account



synchronize all modification into floppy disk

When SG system boot up, all things are loaded into the ram disk, and your modification is also on the ram disk. You have to use 'update' to synchronize the change to the floppy disk.



reboot the SG system disk

If everything is right, you would see some message like 'bidd...BID->;MASTER' appears on the console. Try to telnet to the SG load balancer from remote host and browse the web page of 'http://your.load.balancer.hostname.or.ip'. If everything is right, congratulations!