HAproxy 代理技术原理探究

HAproxy 技术分享

简介

HAProxy是一款提供高可用性、负载均衡以及基于TCP（第四层）和HTTP（第七层）应用的代理软件

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Features

1.免费
2.可以作到4层以上代理
3.高性能
4.高稳定性

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使用案例

淘宝CDN(HTTP反向代理)

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测试:

HTTP代理 ab -i -c 500 -n 100000

| --- node 8910 URL = / HAproxy| --- node 8911 URL = / | --- node 8912 URL = / | --- node 8913 /test/ (reqisetbe ^[^\ ]*\ /(test|uri)/ server_uri_route) #按照规则转发

####### haproxy : (单独由haproxy进行均衡负载) Concurrency Level: 500 Time taken for tests: 32.562 seconds Complete requests: 100000 Failed requests: 0 Write errors: 0 Total transferred: 36606588 bytes HTML transferred: 0 bytes Requests per second: 3071.02 [#/sec] (mean) Time per request: 162.812 [ms] (mean) Time per request: 0.326 [ms] (mean, across all concurrent requests) Transfer rate: 1097.85 [Kbytes/sec] received ####### nginx : (单独由nginx进行均衡负载) Concurrency Level: 500 Time taken for tests: 36.539 seconds Complete requests: 100000 Failed requests: 0 Write errors: 0 Total transferred: 38600000 bytes HTML transferred: 0 bytes Requests per second: 2736.82 [#/sec] (mean) Time per request: 182.694 [ms] (mean) Time per request: 0.365 [ms] (mean, across all concurrent requests) Transfer rate: 1031.65 [Kbytes/sec] received

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对比Nginx

 

Name	Nginx	HAproxy
HTTP代理性能	9	10
TCP 代理性能	0	10
稳定性	10	10
转发规则	10	7
HTTP代理性能	9	10
平滑升级	10	8

原理 epoll 转发

验证 转发方式为以下
经过TCP代理请求 www.baidu.com

client HAProxy Backend curl |----------------->| accept(client) recvfrom(client) sendto(Backent) |-------->| dowith(HAProxy) |<--------| recvfrom(Backend) sendto(Client) |<-----------------| 

strace 查看系统调用

zhangbo3@vm-222:/etc/haproxy$ sudo strace -p 7876
    
    epoll_wait(0, {{EPOLLIN, {u32=5, u64=5}}}, 7, 1000) = 1
 *** (事件循环，监听链接事件) accept(5, { sa_family=AF_INET, sin_port=htons(56479), sin_addr=inet_addr("127.0.0.1") }, [16]) = 1  *** (来自客户端[127.0.0.1]的请求, 端口56479[随机端口]) fcntl(1, F_SETFL, O_RDONLY|O_NONBLOCK) = 0  *** (设置链接socket为非阻塞) setsockopt(1, SOL_TCP, TCP_NODELAY, [1], 4) = 0  *** (设置TCP链接为 NODELAY, 禁止Nagle算法) accept(5, 0x7fff8da2d7a0, [128]) = -1 EAGAIN (Resource temporarily unavailable)  *** (再次去accept链接失败，由于accept被循环包裹，须要返回 EAGAIN才break) recvfrom(1, "GET HTTP://www.baidu.com HTTP/1."..., 8192) = 212  *** (收到来自客户端的请求 curl -x 127.0.0.1:1180 www.baidu.com) recvfrom(1, 0x2560ac4, 7980, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)  *** (返回EAGAIN后break,表示收到完整的TCP数据, 开始处理请求数据) epoll_ctl(0, EPOLL_CTL_ADD, 1, {EPOLLIN, {u32=1, u64=1}}) = 0  *** (未来自客户端的socket加入epoll监听队列) socket(PF_INET, SOCK_STREAM, IPPROTO_TCP) = 2 fcntl(2, F_SETFL, O_RDONLY|O_NONBLOCK) = 0 setsockopt(2, SOL_TCP, TCP_NODELAY, [1], 4) = 0 connect(2, { sa_family=AF_INET, sin_port=htons(8912), sin_addr=inet_addr("127.0.0.1") }, 16) = -1 EINPROGRESS (Operation now in progress)  *** (建立到backend的socket链接,这里backend配置为8912)  *** (server server3 127.0.0.1:8912) sendto(2, "GET HTTP://www.baidu.com HTTP/1."..., 212, MSG_DONTWAIT|MSG_NOSIGNAL, NULL, 0) = 212  *** (发送数据到backend) epoll_wait(0, {}, 7, 0) = 0  *** (继续进入epoll_wait,等待来自backend的数据返回) gettimeofday({1413020002, 322710}, NULL) = 0 recvfrom(2, 0x255c960, 16384, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)  *** (Backend数据来了) epoll_ctl(0, EPOLL_CTL_ADD, 2, {EPOLLIN, {u32=2, u64=2}}) = 0 epoll_wait(0, {{EPOLLIN, {u32=2, u64=2}}}, 7, 1000) = 1 gettimeofday({1413020003, 308930}, NULL) = 0 recvfrom(2, "HTTP/1.1 200 OK\r\nDate: Sat, 11 O"...,16384) = 2896  *** (backend 返回 HTTP 200, 这是标准HTTP协议头) recvfrom(2, 0x255d4b0, 13488, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable) sendto(1, "HTTP/1.1 200 OK\r\nDate: Sat, 11 O"...) = 2896  *** (将backend返回的数据发送到front end) epoll_wait(0, {{EPOLLIN, {u32=2, u64=2}}}, 7, 1000) = 1  *** (继续进入epoll_wait) gettimeofday({1413020003, 309695}, NULL) = 0  *** (客户端链接超时，关闭链接) shutdown(2, 1 /* send */) = 0 close(2) = 0 shutdown(1, 1 /* send */) = 0 close(1) = 0 

验证单进程模型 -> 查看线程数
cat /proc/7878/status

Name:   haproxy
    State:  S (sleeping)
    ...
    Threads:        1 SigQ: 0/15594 SigPnd: 0000000000000000 ShdPnd: 0000000000000000 ...