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README
LGPL-2.1
通讯转发、(负载均衡)通讯分发器 - G5

1.概述
	G5是一款高性能高并发负载、易配置使用、支持远程管理的轻量级TCP/IP的通讯转发、(负载均衡)通讯分发器软件。基于epoll(ET)事件驱动非堵塞全异步无锁框架实现(在非Linux操作系统上退化为select实现),能运行在Linux、UNIX和WINDOWS等多种主流操作系统上。
	G5支持所有TCP应用层协议,这意味着不仅可以用于网站HTTP服务,还能用在SMTP、POP、FTP上等,甚至非常见TCP应用协议。
	G5支持几乎所有主流负载均衡算法,如轮询、最少连接数、最小响应时间等。
	使用场景如下:
	* 简单的TCP通讯转发
	* 与无负载均衡功能的通讯软件配合实现负载均衡分发,避免改造通讯软件带来的工作量和风险
	* 网站反向代理通讯网关

2.开发背景
	今天和系统运维的老大聊天,谈到一直在用的F5,行里对其评价为价格过高、功能复杂难懂,没有发挥相应的价值。因为以前我曾经给行里开发过一个通讯中间件,附带软实现了负载均衡,几年使用下来一直效果不错,突然想自己再软实现一个纯负载均衡通讯分发器,并开源分享给大家。
	说干就干,回到家,搜了一下网上同类软件,整理技术需求,
	软件定义如下:
	基于规则的通讯转发、分发。客户端连入时,根据来源网络地址和本地侦听端口查询转发规则,参照负载均衡算法分发到目标网络地址集合中的其中一个。
	
	实现目标如下:
	* 支持长/短TCP,后续还会支持UDP
	* 与应用层协议无关,即支持HTTP,FTP,SMTP,POP,TELNET,SSH等等所有应用层协议
	* 稳定高效,Linux下首选epoll(ET模式),全异步设计;WINDOWS和类UNIX用select实现
	* 转发分发规则配置文件;也支持远程在线管理规则,以及查询状态
	* 支持多种主流负载均衡算法
	* 源码和可执行程序体型轻巧,概念简单,使用快捷
	
	支持负载均衡算法有:
	* 主备模式,即一直连接第一个目标地址,如果第一个目标地址故障了,切换到下一个目标地址
	* 轮询模式,把所有目标地址按次序依次循环使用
	* 最少连接数模式,在目标地址集合中挑选当前最少连接的目标
	* 最小响应时间模式,在目标地址集合中挑选历史数据交换最快的目标
	* 随机模式,随机选择目标地址
	* HASH模式,根据来源地址计算HASH得到一个唯一固定的目标地址
	
	完整实现基于epoll(ET)的非堵塞全异步应用层框架,主要包含以下内容:
	* 基于epoll(ET)事件处理应用层框架。
	* accept客户端连接后转连服务端connect的非堵塞异步实现。
	* recv客户端数据后转发send服务端时,当转发速度小于接收速度情况下的非堵塞异步实现。
	* 客户端和服务端的请求和响应在转发端的并发隔离。
	
	研发之前,取个好听的名字,相对于硬实现F5,就取名为软实现G5吧 ^_^
	经过5个晚上的奋笔疾书,捣鼓出第一版,源代码只有一个.c(2400行)和一个.h文件(260行),编译链接出可执行程序约70KB大小。
	
3.安装部署
	从http://git.oschina.net/calvinwilliams/G5下载源码安装包,在你的临时目录解开
	$ tar xvzf G5-x.x.x.tar.gz
	$ cd G5-x.x.x/src
	$ make -f makefile.Linux clean
	$ make -f makefile.Linux install
	因为只有一对源文件,所以编译链接很快,也便于编译器优化,更便于你自己手工编译。
	如果不报错的话,可执行程序G5就安装到/usr/bin/下了。
	
4.基本使用
4.1.命令行参数
	不带参数执行G5会显示版本、命令行参数说明等信息
	$ G5
	G5 - tcp LB dispatch
	v1.0.0 build Apr  6 2014 15:00:31 WITH 100:1024:4096,10:3:100,64
	Copyright by calvin 2014
	Email : calvinwilliams.c@gmail.com
	
	USAGE : G5 -f config_pathfilename [ -r forward_rule_maxcount ] [ -s forward_session_maxcount ] [ -b transfer_bufsize ] [ -d ]
	
4.2.启动
	因为是工具型软件,所以用户界面设计的比较简单,自行编写一个分发规则配置文件
	$ cat demo.conf
	admin G 192.168.1.54:* - 192.168.1.54:8060 ;
	webdog MS 192.168.1.54:* - 192.168.1.54:8070 > 192.168.1.79:8088 ;
	webdog2 RR *.*.*.*:* - 192.168.1.54:8080 > 192.168.1.79:8089 192.168.1.79:8090 192.168.1.79:8091 ;
	作为G5唯一一个必须的命令行参数-f启动
	$ G5 -f demo.conf
	G5 - tcp LB dispatch
	v1.1.0 build Apr 12 2014 03:57:33 WITH 100:1024:4096,10:3:100,64
	Copyright by calvin 2014
	Email : calvinwilliams.c@gmail.com
	forward_rule_maxcount    [100]
	forward_session_maxcount [1024]
	transfer_bufsize         [4096]bytes
	epoll_create ok #3#
	2014-04-12 03:59:05 | admin G 192.168.1.54:* - 192.168.1.54:8060(LISTEN)#5# ;
	2014-04-12 03:59:05 | webdog MS 192.168.1.54:* 192.168.1.79:* - 192.168.1.54:8070(LISTEN)#7# > 192.168.1.79:8088 ;
	2014-04-12 03:59:05 | webdog2 RR *.*.*.*:* - 192.168.1.54:8080(LISTEN)#8# > 192.168.1.79:8089 192.168.1.79:8090 192.168.1.79:8091 ;
	...
	之后产生的所有普通信息、错误都输出到标准输出、错误输出上,如果启动参数加上-d,则还会输出所有调试信息,如连接、断开、数据分发
	
	我模拟发起一个HTTP请求
	$ lynx http://192.168.1.54:8080/index.php
	G5的标准输出上产生如下信息
	2014-04-12 03:60:05 | forward2 [192.168.1.54:43477]#3# - [192.168.1.54:8080]#7# > [192.168.1.79:8089]#8#
	2014-04-12 03:60:05 | transfer #3# [324]bytes to #8#
	2014-04-12 03:60:05 | transfer #8# [257]bytes to #3#
	2014-04-12 03:60:05 | close #8# recv 0
	说明一下
	192.168.1.54:43477(lynx)连接192.168.1.54:8080(G5)被转发到网站服务器192.168.1.79:8089(apache)
	lynx发送了HTTP请求324字节给网站服务器
	lynx从网站服务器接收了HTTP响应257字节
	服务端首先断开连接
	
	一般都使用nohup使其变为守护进程,输出导向到文件
	$ nohup G5 demo.conf >demo.log 2>&1 &
	
4.3.停止
	别客气,直接kill (pid)即可。

4.4.作为WINDOWS服务运行
	安装作为WINDOWS服务
	$ G5 ... --install-service
	
	卸载WINDOWS服务
	$ G5 ... --uninstall-service
	
5.配置文件
	配置文件里一行为一条转发规则,每条规则由三大段组成:规则名称、规则类型和规则实体,之间用白字符(空格、TAB)隔开。
	
5.1.规则名称
	唯一标识该规则,便于新增、修改和删除规则。
	
5.2.规则类型
	说明该规则是在线管理(G),还是以某种通讯分发算法。目前实现的算法列表如下
	MS : 主备模式
	RR : 轮询模式
	LC : 最少连接数模式
	RT : 最小响应时间模式
	RD : 随机模式
	HS : HASH模式
	
5.3.规则实体
	格式为"来源地址集合 - 本地转发地址集合 > 目标地址集合 ;",其中三个地址集合内可以包含一个地址或白字符隔开的地址列表。单个地址由"IP:PORT"组成。来源单个地址中的IP和PORT可以使用'*'和'?'通配。当只有一个目标地址时,通讯分发算法就没有意义了。
	
5.4.属性
	规则类型可选追加属性集合格式为"( 属性1名称 属性1值 属性2名称 属性2值 ... )",之间用白字符(空格、TAB)隔开。目前可用的属性有
		timeout 秒数
		maxclient 最大客户端会话数量(全局)
	规则实体内来源地址集合可选追加属性集合同规则类型属性集合。目前可用的属性有
		maxclient 最大客户端会话数量(单个规则实体内来源地址集合)
	
5.5.示例
	回来解释一下前面展示的配置文件
	$ cat demo.conf
	# 只允许本机192.168.1.54连接到G5在线管理规则,管理连接空闲超时为5分钟,超时时强制断开
	admin G ( timeout 300 ) 192.168.1.54:* - 192.168.1.54:8060 ;
	# 本地所有TCP连接到本机8070端口时统统转发到192.168.1.79:8088
	# 用于跨网段的通讯转发,空闲超时为2分钟,超时时强制断开,最大客户端会话数量为5个,多余连接将被强制断开
	webdog MS ( timeout 120 ) 192.168.1.54:* 192.168.1.79:* - 192.168.1.54:8070 > 192.168.1.79:8088 ;
	# 允许所有主机连接192.168.1.79:8089,并以轮询算法分发给三个服务器192.168.1.79:8089 192.168.1.79:8090 192.168.1.79:8091
	# 用于网站前端负载均衡通讯节点
	webdog2 RR *.*.*.*:* ( maxclients 5 ) - 192.168.1.54:8080 > 192.168.1.79:8089 192.168.1.79:8090 192.168.1.79:8091 ;
	还简单吧
	
6.在线管理
	G5在启动时必须指定一个配置文件装载所有规则并以之工作,也支持远程连接上管理端口在线管理规则,用telnet即可
	$ telnet 192.168.1.54 8060
	Trying 192.168.1.54...
	Connected to rhel54 (192.168.1.54).
	Escape character is '^]'.
	>
	'>'为输入提示符,后面可以键入的命令有
	ver : 显示G5版本及编译日期时间
	quit : 断开管理连接
	list rules : 显示当前所有转发规则
	add rule (...规则...) : 新增转发规则
	modify rule (...规则...) : 修改转发规则
	remove rule (规则名称) : 删除转发规则
	dump rule : 保存所有转发规则到启动时指定的配置文件中
	list forwards : 显示当前所有转发连接信息
	
	使用示例
	$ telnet 192.168.1.54 8060
	Trying 192.168.1.54...
	Connected to rhel54 (192.168.1.54).
	Escape character is '^]'.
	> ver
	version v1.0.0 build Apr  3 2014 08:05:54
	> list rules
	    1 : admin G ( timeout 300 ) 192.168.1.54:* ( conntions[1/2] ) - 192.168.1.54:8060 ;
	    2 : webdog MS ( timeout 120 ) 192.168.1.54:* 192.168.1.79:* - 192.168.1.54:8070 > 192.168.1.79:8088 ;
	    3 : webdog2 RR *.*.*.*:* ( conntions[0/100] ) - 192.168.1.54:8080 > 192.168.1.79:8089 192.168.1.79:8090 192.168.1.79:8091 ;
	> add rule webdog3 MS 192.168.1.54:* - 192.168.1.54:8070 > 192.168.1.79:8088 ;
	add forward rule ok
	> modify rule webdog3 HS 192.168.1.54:* - 192.168.1.54:8070 > 192.168.1.79:8088 ;
	modify forward rule ok
	> remove rule webdog3
	remove forward rule ok
	> dump rules
	dump all forward rules ok
	> list forwards
	    1 : LISTEN [192.168.1.54:8060]#5#
	    2 : LISTEN [192.168.1.54:8060]#6#
	    3 : LISTEN [192.168.1.54:8070]#7#
	    4 : LISTEN [192.168.1.54:8080]#8#
	    5 : CLIENT [192.168.1.54:54162]#4# - MANAGE [192.168.1.54:8060]#5#
	 2138 : CLIENT [192.168.1.54:39869]#11# < LISTEN [192.168.1.54:8080]#8# - SERVER [192.168.1.79:8090]#12# connected
	 2139 : CLIENT [192.168.1.54:39869]#11# - LISTEN [192.168.1.54:8080]#8# > SERVER [192.168.1.79:8090]#12# connected
	 2140 : CLIENT [192.168.1.54:39871]#27# < LISTEN [192.168.1.54:8080]#8# - SERVER [192.168.1.79:8091]#28# connected
	 2141 : CLIENT [192.168.1.54:39871]#27# - LISTEN [192.168.1.54:8080]#8# > SERVER [192.168.1.79:8091]#28# connected
	 2142 : CLIENT [192.168.1.54:39873]#17# < LISTEN [192.168.1.54:8080]#8# - SERVER [192.168.1.79:8089]#18# connected
	 2143 : CLIENT [192.168.1.54:39875]#25# < LISTEN [192.168.1.54:8080]#8# - SERVER [192.168.1.79:8090]#26# connected
	 2144 : CLIENT [192.168.1.54:39875]#25# - LISTEN [192.168.1.54:8080]#8# > SERVER [192.168.1.79:8090]#26# connected
	 2145 : CLIENT [192.168.1.54:39873]#17# - LISTEN [192.168.1.54:8080]#8# > SERVER [192.168.1.79:8089]#18# connected
	 2146 : CLIENT [192.168.1.54:39877]#21# < LISTEN [192.168.1.54:8080]#8# - SERVER [192.168.1.79:8091]#22# connected
	 2147 : CLIENT [192.168.1.54:39877]#21# - LISTEN [192.168.1.54:8080]#8# > SERVER [192.168.1.79:8091]#22# connected
	 2148 : CLIENT [192.168.1.54:39879]#9# < LISTEN [192.168.1.54:8080]#8# - SERVER [192.168.1.79:8089]#10# connected
	 2149 : CLIENT [192.168.1.54:39879]#9# - LISTEN [192.168.1.54:8080]#8# > SERVER [192.168.1.79:8089]#10# connected
	 2150 : CLIENT [192.168.1.54:39881]#15# < LISTEN [192.168.1.54:8080]#8# - SERVER [192.168.1.79:8090]#16# connected
	 2151 : CLIENT [192.168.1.54:39881]#15# - LISTEN [192.168.1.54:8080]#8# > SERVER [192.168.1.79:8090]#16# connected
	 2152 : CLIENT [192.168.1.54:39883]#19# < LISTEN [192.168.1.54:8080]#8# - SERVER [192.168.1.79:8091]#20# connected
	 2153 : CLIENT [192.168.1.54:39884]#23# < LISTEN [192.168.1.54:8080]#8# - SERVER [192.168.1.79:8089]#24# connected
	 2154 : CLIENT [192.168.1.54:39884]#23# - LISTEN [192.168.1.54:8080]#8# > SERVER [192.168.1.79:8089]#24# connected
	 2155 : CLIENT [192.168.1.54:39883]#19# - LISTEN [192.168.1.54:8080]#8# > SERVER [192.168.1.79:8091]#20# connected
	 2156 : CLIENT [192.168.1.54:39887]#13# < LISTEN [192.168.1.54:8080]#8# - SERVER [192.168.1.79:8090]#14# connected
	 2157 : CLIENT [192.168.1.54:39887]#13# - LISTEN [192.168.1.54:8080]#8# > SERVER [192.168.1.79:8090]#14# connected
	> clean forwards
	clean forwards ok
	> quit
	Connection closed by foreign host.
	$
	
	注意:慎用dump rules
	
7.性能测试
	因为是简单的通讯转发、分发器,内部使用epoll(ET)+全异步实现,达到高并发和充分负载均衡,几乎可以榨干单核硬件资源。
	由于我没有完整靠谱的压测环境,只能在我的老爷机上做直连和通过G5转连的性能比较差异。
	
	压测硬件(2007年买的老爷机)
		CPU  : Intel Dual E2160 1.8GHz 1.81GHz
		内存 : 2GB
		硬盘 : 希捷 250GB 7200转
	压测软件
		Windows XP SP3 ( VMware 6.0 ( RedHat Enterprise Linux 5.4 分了256MB内存 ) )
	压测场景
		ab直连apache 和 ab通过G5转发给apache
		并发数100,总请求数10000次
	
	首先是192.168.1.54:*(apache ab)直连192.168.1.79:8090(apache 2.2.13 for win32),

	Server Software:        Apache/2.2.13
	Server Hostname:        192.168.1.79
	Server Port:            8090
	
	Document Path:          /index.html
	Document Length:        44 bytes
	
	Concurrency Level:      100
	Time taken for tests:   12.503706 seconds
	Complete requests:      10000
	Failed requests:        0
	Write errors:           0
	Total transferred:      3160000 bytes
	HTML transferred:       440000 bytes
	Requests per second:    799.76 [#/sec] (mean)
	Time per request:       125.037 [ms] (mean)
	Time per request:       1.250 [ms] (mean, across all concurrent requests)
	Transfer rate:          246.73 [Kbytes/sec] received
	
	Connection Times (ms)
	             min  mean[+/-sd] median   max
	Connect:        0    0   4.4      0      86
	Processing:    11  123  31.7    113     283
	Waiting:        8  122  31.6    112     281
	Total:         28  123  31.9    113     284
	
	Percentage of the requests served within a certain time (ms)
	 50%    113
	 66%    115
	 75%    117
	 80%    120
	 90%    163
	 95%    187
	 98%    249
	 99%    256
	100%    284 (longest request)

	然后是192.168.1.54:*(apache ab)发往192.168.1.54:8080(G5)(主备模式MS)分发给192.168.1.79:8089,8090,8091(apache 2.2.13 for win32),

	Server Software:        Apache/2.2.13
	Server Hostname:        192.168.1.54
	Server Port:            8080
	
	Document Path:          /index.html
	Document Length:        44 bytes
	
	Concurrency Level:      100
	Time taken for tests:   14.235889 seconds
	Complete requests:      10000
	Failed requests:        0
	Write errors:           0
	Total transferred:      3160000 bytes
	HTML transferred:       440000 bytes
	Requests per second:    702.45 [#/sec] (mean)
	Time per request:       142.359 [ms] (mean)
	Time per request:       1.424 [ms] (mean, across all concurrent requests)
	Transfer rate:          216.71 [Kbytes/sec] received
	
	Connection Times (ms)
	             min  mean[+/-sd] median   max
	Connect:        0    0   8.3      0     154
	Processing:    25  140  31.3    132     335
	Waiting:       22  139  31.2    131     334
	Total:         70  140  32.3    132     338
	
	Percentage of the requests served within a certain time (ms)
	 50%    132
	 66%    134
	 75%    137
	 80%    140
	 90%    175
	 95%    190
	 98%    275
	 99%    295
	100%    338 (longest request)

	然后是192.168.1.54:*(apache ab)发往192.168.1.54:8080(G5)(轮询模式RR)分发给192.168.1.79:8089,8090,8091(apache 2.2.13 for win32),

	Server Software:        Apache/2.2.13
	Server Hostname:        192.168.1.54
	Server Port:            8080
	
	Document Path:          /index.html
	Document Length:        44 bytes
	
	Concurrency Level:      100
	Time taken for tests:   14.15712 seconds
	Complete requests:      10000
	Failed requests:        0
	Write errors:           0
	Total transferred:      3160316 bytes
	HTML transferred:       440044 bytes
	Requests per second:    713.48 [#/sec] (mean)
	Time per request:       140.157 [ms] (mean)
	Time per request:       1.402 [ms] (mean, across all concurrent requests)
	Transfer rate:          220.18 [Kbytes/sec] received
	
	Connection Times (ms)
	             min  mean[+/-sd] median   max
	Connect:        0    0   7.5      0     140
	Processing:    26  137  67.8     91     342
	Waiting:       25  137  67.8     90     340
	Total:         49  138  68.1     91     347
	
	Percentage of the requests served within a certain time (ms)
	 50%     91
	 66%    178
	 75%    219
	 80%    222
	 90%    229
	 95%    259
	 98%    273
	 99%    279
	100%    347 (longest request)

	然后是192.168.1.54:*(apache ab)发往192.168.1.54:8080(G5)(最小响应时间模式RT)分发给192.168.1.79:8089,8090,8091(apache 2.2.13 for win32),

	Server Software:        Apache/2.2.13
	Server Hostname:        192.168.1.54
	Server Port:            8080
	
	Document Path:          /index.html
	Document Length:        44 bytes
	
	Concurrency Level:      100
	Time taken for tests:   14.260485 seconds
	Complete requests:      10000
	Failed requests:        0
	Write errors:           0
	Total transferred:      3160000 bytes
	HTML transferred:       440000 bytes
	Requests per second:    701.24 [#/sec] (mean)
	Time per request:       142.605 [ms] (mean)
	Time per request:       1.426 [ms] (mean, across all concurrent requests)
	Transfer rate:          216.33 [Kbytes/sec] received
	
	Connection Times (ms)
	             min  mean[+/-sd] median   max
	Connect:        0    0   7.7      0     148
	Processing:    29  140  27.3    133     346
	Waiting:       26  139  27.2    132     346
	Total:         65  141  28.4    133     346
	
	Percentage of the requests served within a certain time (ms)
	 50%    133
	 66%    136
	 75%    138
	 80%    140
	 90%    181
	 95%    190
	 98%    241
	 99%    287
	100%    346 (longest request)

	然后是192.168.1.54:*(apache ab)发往192.168.1.54:8080(G5)(随机模式RD)分发给192.168.1.79:8089,8090,8091(apache 2.2.13 for win32),

	Server Software:        Apache/2.2.13
	Server Hostname:        192.168.1.54
	Server Port:            8080
	
	Document Path:          /index.html
	Document Length:        44 bytes
	
	Concurrency Level:      100
	Time taken for tests:   14.114779 seconds
	Complete requests:      10000
	Failed requests:        0
	Write errors:           0
	Total transferred:      3160632 bytes
	HTML transferred:       440088 bytes
	Requests per second:    708.48 [#/sec] (mean)
	Time per request:       141.148 [ms] (mean)
	Time per request:       1.411 [ms] (mean, across all concurrent requests)
	Transfer rate:          218.64 [Kbytes/sec] received
	
	Connection Times (ms)
	             min  mean[+/-sd] median   max
	Connect:        0    0   7.3      0     139
	Processing:    22  138  67.3     92     354
	Waiting:       21  138  67.3     92     353
	Total:         48  139  67.6     92     356
	
	Percentage of the requests served within a certain time (ms)
	 50%     92
	 66%    184
	 75%    212
	 80%    221
	 90%    239
	 95%    255
	 98%    279
	 99%    292
	100%    356 (longest request)
	
	可以看出,转发的总耗时比直连多了10%左右,大体还是可以接受的,如果G5和WebServer分开部署在不同机器里,G5就能发挥出负载均衡的优势,性能也会大幅提升。
	以后若有更好的环境,我将会做更全面更深入的压测。

8.最后
	作为一个负载均衡通讯转发分发网络工具,G5基本实现设计目标,并发布出来分享给开源世界,欢迎使用。
	G5源代码作为epoll(ET)+全异步综合使用示例也供大家学习参考,欢迎批评指正。
	如有问题或建议欢迎联系我
	开源项目首页 : http://git.oschina.net/calvinwilliams/G5
	作者邮箱 : calvinwilliams.c@gmail.com

附录A.待开发内容
(无)
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