haproxy代理服务

HAProxy:

LB Cluster:

        四层：   lvs, nginx(stream)，haproxy(mode tcp)

        七层：   http: nginx(http, ngx_http_upstream_module), haproxy(mode http), httpd, ats, perlbal, pound…

HAProxy：

             http://www.haproxy.org

             http://www.haproxy.com 

文档参考：

            http://cbonte.github.io/haproxy-dconv/

HAProxy is a TCP/HTTP reverse proxy which is particularly suited for high availability environments. Indeed, it can:

 – route HTTP requests depending on statically assigned cookies

 – spread load among several servers while assuring server persistence

   through the use of HTTP cookies

 – switch to backup servers in the event a main server fails

 – accept connections to special ports dedicated to service monitoring

 – stop accepting connections without breaking existing ones

 – add, modify, and delete HTTP headers in both directions

 – block requests matching particular patterns

 – report detailed status to authenticated users from a URI intercepted by the application

程序环境：
主程序：/usr/sbin/haproxy
主配置文件：/etc/haproxy/haproxy.cfg
Unit file：/usr/lib/systemd/system/haproxy.service

配置段：
        global：全局配置段
                   进程及安全配置相关的参数
                   性能调整相关参数
                   Debug参数
        proxies：代理配置段
                defaults：为frontend, listen, backend提供默认配置；
                fronted：前端，相当于nginx, server {}
                backend：后端，相当于nginx, upstream {}
                listen：同时拥前端和后端

简单的配置示例：
frontend web                                #定义前端名字
bind *:80                                      #监听服务器上的80端口，可以监听具体地址端口
default_backend     websrvs            #默认后端   websrvs

backend websrvs                            #定义后端名字，和前对定义的后端名字统一
balance roundrobin                          # 算法  动态轮询
server srv1 172.16.100.6:80 check             #后端服务器地址和端口，check是做健康检查
server srv2 172.16.100.7:80 check

global配置参数：
          进程及安全管理：chroot, deamon，user, group, uid, gid

log：定义全局的syslog服务器；最多可以定义两个；
          log <address> [len <length>] <facility> [max level [min level]]

nbproc <number>：要启动的haproxy的进程数量；
ulimit-n <number>：每个haproxy进程可打开的最大文件数；

性能调整：

maxconn <number>：设定每个haproxy进程所能接受的最大并发连接数；

                        Sets the maximum per-process number of concurrent connections to <number>.

maxconnrate <number>：Sets the maximum per-process number of connections per second to <number>. 

                        每个进程每秒种所能创建的最大连接数量；

maxsessrate <number>：
maxsslconn <number>: Sets the maximum per-process number of concurrent SSL connections to <number>.
spread-checks <0..50, in percent>

代理配置段：                               #后面的name都是随便定义，和作用相关
– defaults <name>
– frontend <name>
– backend  <name>
– listen   <name>

A “frontend” section describes a set of listening sockets accepting client connections.
A “backend” section describes a set of servers to which the proxy will connect to forward incoming connections.
A “listen” section defines a complete proxy with its frontend and backend parts combined in one section. It is generally useful for TCP-only traffic.

All proxy names must be formed from upper and lower case letters, digits, ‘-‘ (dash), ‘_’ (underscore) , ‘.’ (dot) and ‘:’ (colon). 区分字符大小写；

配置参数：

bind：Define one or several listening addresses and/or ports in a frontend.
bind [<address>]:<port_range> [, …] [param*]

listen http_proxy
bind :80,:443
bind 10.0.0.1:10080,10.0.0.1:10443
bind /var/run/ssl-frontend.sock user root mode 600 accept-proxy

balance：后端服务器组内的服务器调度算法
balance <algorithm> [ <arguments> ]
balance url_param <param> [check_post]

算法：
         roundrobin：Each server is used in turns, according to their weights.
                server options： weight #
                          动态算法：支持权重的运行时调整，支持慢启动；每个后端中最多支持4095个server；
                static-rr：
                          静态算法：不支持权重的运行时调整及慢启动；后端主机数量无上限；

leastconn：
     推荐使用在具有较长会话的场景中，例如MySQL、LDAP等；

first：
     根据服务器在列表中的位置，自上而下进行调度；前面服务器的连接数达到上限，新请求才会分配给下一台服务；

source：源地址hash；
           除权取余法：
           一致性哈希：

uri：
对URI的左半部分做hash计算，并由服务器总权重相除以后派发至某挑出的服务器；

<scheme>://<user>:<password>@<host>:<port>/<path>;<params>?<query>#<frag>
左半部分：/<path>;<params>
整个uri：/<path>;<params>?<query>#<frag>

url_param：对用户请求的uri听<params>部分中的参数的值作hash计算，并由服务器总权重相除以后派发至某挑出的服务器；通常用于追踪用户，以确保来自同一个用户的请求始终发往同一个Backend Server；

hdr(<name>)：对于每个http请求，此处由<name>指定的http首部将会被取出做hash计算； 并由服务器总权重相除以后派发至某挑出的服务器；没有有效值的会被轮询调度； 
hdr(Cookie)

rdp-cookie
rdp-cookie(<name>)

hash-type：哈希算法
         hash-type <method> <function> <modifier>
                    map-based：除权取余法，哈希数据结构是静态的数组；
                    consistent：一致性哈希，哈希数据结构是一个树；

<function> is the hash function to be used : 哈希函数
       sdbm
       djb2
       wt6

default_backend <backend>
         设定默认的backend，用于frontend中；

default-server [param*]
         为backend中的各server设定默认选项；

回顾：
tcp/http reverse proxy；
haproxy.cfg
global, proxies
proxies：
defaults
frontend
listen
backend

proxies：bind、balance、hash-type、default_backend、server
balance：
        roundrobin、static-rr、leastconn、first、source、uri、hdr(<HEADER>)、url_param、…

HAProxy(2)
server <name> <address>[:[port]] [param] 
               定义后端主机的各服务器及其选项；

<name>：服务器在haproxy上的内部名称；出现在日志及警告信息；
<address>：服务器地址，支持使用主机名；
[:[port]]：端口映射；省略时，表示同bind中绑定的端口；
[param]：参数
maxconn <maxconn>：当前server的最大并发连接数；
backlog <backlog>：当前server的连接数达到上限后的后援队列长度；
backup：设定当前server为备用服务器；
check：对当前server做健康状态检测；
addr ：检测时使用的IP地址；
port ：针对此端口进行检测；
inter <delay>：连续两次检测之间的时间间隔，默认为2000ms; 
rise <count>：连续多少次检测结果为“成功”才标记服务器为可用；默认为2；
fall <count>：连续多少次检测结果为“失败”才标记服务器为不可用；默认为3；

注意：httpchk，”smtpchk”, “mysql-check”, “pgsql-check” and “ssl-hello-chk” 用于定义应用层检测方法；

cookie <value>：为当前server指定其cookie值，用于实现基于cookie的会话黏性；
disabled：标记为不可用；
redir <prefix>：将发往此server的所有GET和HEAD类的请求重定向至指定的URL；
weight <weight>：权重，默认为1;

统计接口启用相关的参数 ：           
   stats enable
启用统计页；基于默认的参数启用stats page；
– stats uri   : /haproxy?stats
– stats realm : “HAProxy Statistics”
– stats auth  : no authentication
– stats scope : no restriction

stats auth <user>:<passwd>
认证时的账号和密码，可使用多次；

stats realm <realm>
认证时的realm；

stats uri <prefix>
自定义stats page uri

stats refresh <delay>
设定自动刷新时间间隔；

stats admin { if | unless } <cond>
启用stats page中的管理功能

配置示例：
listen stats
bind :9099
stats enable
stats realm HAPorxy\ Stats\ Page
stats auth admin:admin
stats admin if TRUE

maxconn <conns>：为指定的frontend定义其最大并发连接数；默认为2000；
Fix the maximum number of concurrent connections on a frontend.  

mode { tcp|http|health }
          定义haproxy的工作模式；
                        tcp：基于layer4实现代理；可代理mysql, pgsql, ssh, ssl等协议；
                        http：仅当代理的协议为http时使用； 
                      health：工作为健康状态检查的响应模式，当连接请求到达时回应“OK”后即断开连接；

示例：
listen ssh
bind :22022
balance leastconn
mode tcp
server sshsrv1 172.16.100.6:22 check
server sshsrv2 172.16.100.7:22 check

cookie <name> [ rewrite | insert | prefix ] [ indirect ] [ nocache ]  [ postonly ] [ preserve ] [ httponly ] [ secure ]  [ domain <domain> ]* [ maxidle <idle> ] [ maxlife <life> ]
<name>：is the name of the cookie which will be monitored, modified or inserted in order to bring persistence.
rewirte：重写；
insert：插入；
prefix：前缀；

基于cookie的session sticky的实现：
backend websrvs
cookie WEBSRV insert nocache indirect
server srv1 172.16.100.6:80 weight 2 check rise 1 fall 2 maxconn 3000 cookie srv1
server srv2 172.16.100.7:80 weight 1 check rise 1 fall 2 maxconn 3000 cookie srv2

option forwardfor [ except <network> ] [ header <name> ] [ if-none ]
Enable insertion of the X-Forwarded-For header to requests sent to servers

在由haproxy发往后端主机的请求报文中添加“X-Forwarded-For”首部，其值前端客户端的地址；用于向后端主发送真实的客户端IP；
[ except <network> ]：请求报请来自此处指定的网络时不予添加此首部；
[ header <name> ]：使用自定义的首部名称，而非“X-Forwarded-For”；

errorfile <code> <file>
Return a file contents instead of errors generated by HAProxy

<code>：is the HTTP status code. Currently, HAProxy is capable of  generating codes 200, 400, 403, 408, 500, 502, 503, and 504.
<file>：designates a file containing the full HTTP response.

示例：
errorfile 400 /etc/haproxy/errorfiles/400badreq.http
errorfile 408 /dev/null  # workaround Chrome pre-connect bug
errorfile 403 /etc/haproxy/errorfiles/403forbid.http
errorfile 503 /etc/haproxy/errorfiles/503sorry.http

errorloc <code> <url>
errorloc302 <code> <url>

errorfile 403 http://www.magedu.com/error_pages/403.html

reqadd  <string> [{if | unless} <cond>]
Add a header at the end of the HTTP request

rspadd <string> [{if | unless} <cond>]
Add a header at the end of the HTTP response

rspadd X-Via:\ HAPorxy

reqdel  <search> [{if | unless} <cond>]
reqidel <search> [{if | unless} <cond>]  (ignore case)
Delete all headers matching a regular expression in an HTTP request

rspdel  <search> [{if | unless} <cond>]
rspidel <search> [{if | unless} <cond>]  (ignore case)
Delete all headers matching a regular expression in an HTTP response

rspidel  Server.

注意：
默认发往本机的日志服务器；
(1) local2.      /var/log/local2.log 
(2) $ModLoad imudp
$UDPServerRun 514

log-format <string>：
课外实践：参考文档实现combined格式的记录

capture cookie <name> len <length>
Capture and log a cookie in the request and in the response.

capture request header <name> len <length>
Capture and log the last occurrence of the specified request header.

capture request header X-Forwarded-For len 15

capture response header <name> len <length>
Capture and log the last occurrence of the specified response header.

capture response header Content-length len 9
capture response header Location len 15

为指定的MIME类型启用压缩传输功能
compression algo <algorithm> …：   启用http协议的压缩机制，指明压缩算法gzip, deflate；
compression type <mime type> …：指明压缩的MIMI类型；

对后端服务器做http协议的健康状态检测：
option httpchk
option httpchk <uri>
option httpchk <method> <uri>
option httpchk <method> <uri> <version>
定义基于http协议的7层健康状态检测机制；

http-check expect [!] <match> <pattern>
Make HTTP health checks consider response contents or specific status codes.

连接超时时长：
timeout client <timeout>
Set the maximum inactivity time on the client side. 默认单位是毫秒; 

timeout server <timeout>
Set the maximum inactivity time on the server side.

timeout http-keep-alive <timeout>
持久连接的持久时长；

timeout http-request <timeout>
Set the maximum allowed time to wait for a complete HTTP request

timeout connect <timeout>
Set the maximum time to wait for a connection attempt to a server to succeed.

timeout client-fin <timeout>
Set the inactivity timeout on the client side for half-closed connections.

timeout server-fin <timeout>
Set the inactivity timeout on the server side for half-closed connections.

use_backend <backend> [{if | unless} <condition>]
Switch to a specific backend if/unless an ACL-based condition is matched.
当符合指定的条件时使用特定的backend；

block { if | unless } <condition>
Block a layer 7 request if/unless a condition is matched

acl invalid_src src 172.16.200.2
block if invalid_src
errorfile 403 /etc/fstab

http-request { allow | deny } [ { if | unless } <condition> ]
Access control for Layer 7 requests

tcp-request connection {accept|reject}  [{if | unless} <condition>]
Perform an action on an incoming connection depending on a layer 4 condition

示例：
listen ssh
bind :22022
balance leastconn
acl invalid_src src 172.16.200.2
tcp-request connection reject if invalid_src
mode tcp
server sshsrv1 172.16.100.6:22 check
server sshsrv2 172.16.100.7:22 check backup

acl：
The use of Access Control Lists (ACL) provides a flexible solution to perform content switching and generally to take decisions based on content extracted from the request, the response or any environmental status.

acl <aclname> <criterion> [flags] [operator] [<value>] …
<aclname>：ACL names must be formed from upper and lower case letters, digits, ‘-‘ (dash), ‘_’ (underscore) , ‘.’ (dot) and ‘:’ (colon).ACL names are case-sensitive.

<value>的类型：
– boolean
– integer or integer range
– IP address / network
– string (exact, substring, suffix, prefix, subdir, domain)
– regular expression
– hex block

<flags>
-i : ignore case during matching of all subsequent patterns.
-m : use a specific pattern matching method
-n : forbid the DNS resolutions
-u : force the unique id of the ACL
— : force end of flags. Useful when a string looks like one of the flags.

[operator] 
匹配整数值：eq、ge、gt、le、lt

匹配字符串：
– exact match     (-m str) : the extracted string must exactly match the patterns ;
– substring match (-m sub) : the patterns are looked up inside the extracted string, and the ACL matches if any of them is found inside ;
– prefix match    (-m beg) : the patterns are compared with the beginning of the extracted string, and the ACL matches if any of them matches.
– suffix match    (-m end) : the patterns are compared with the end of the extracted string, and the ACL matches if any of them matches.
– subdir match    (-m dir) : the patterns are looked up inside the extracted string, delimited with slashes (“/”), and the ACL matches if any of them matches.
– domain match    (-m dom) : the patterns are looked up inside the extracted string, delimited with dots (“.”), and the ACL matches if any of them matches.

acl作为条件时的逻辑关系：
– AND (implicit)
– OR  (explicit with the “or” keyword or the “||” operator)
– Negation with the exclamation mark (“!”)

if invalid_src invalid_port
if invalid_src || invalid_port
if ! invalid_src invalid_port

<criterion> ：
dst : ip
dst_port : integer
src : ip
src_port : integer

acl invalid_src  src  172.16.200.2

path : string
This extracts the request’s URL path, which starts at the first slash and ends before the question mark (without the host part).
/path;<params>

path     : exact string match
path_beg : prefix match
path_dir : subdir match
path_dom : domain match
path_end : suffix match
path_len : length match
path_reg : regex match
path_sub : substring match

url : string
This extracts the request’s URL as presented in the request. A typical use is with prefetch-capable caches, and with portals which need to aggregate multiple information from databases and keep them in caches.

url     : exact string match
url_beg : prefix match
url_dir : subdir match
url_dom : domain match
url_end : suffix match
url_len : length match
url_reg : regex match
url_sub : substring match

req.hdr([<name>[,<occ>]]) : string
This extracts the last occurrence of header <name> in an HTTP request.

hdr([<name>[,<occ>]])     : exact string match
hdr_beg([<name>[,<occ>]]) : prefix match
hdr_dir([<name>[,<occ>]]) : subdir match
hdr_dom([<name>[,<occ>]]) : domain match
hdr_end([<name>[,<occ>]]) : suffix match
hdr_len([<name>[,<occ>]]) : length match
hdr_reg([<name>[,<occ>]]) : regex match
hdr_sub([<name>[,<occ>]]) : substring match

示例：
acl bad_curl hdr_sub(User-Agent) -i curl
block if bad_curl

status : integer
Returns an integer containing the HTTP status code in the HTTP response.

Pre-defined ACLs
ACL name Equivalent to Usage
FALSE always_false never match
HTTP req_proto_http match if protocol is valid HTTP
HTTP_1.0 req_ver 1.0 match HTTP version 1.0
HTTP_1.1 req_ver 1.1 match HTTP version 1.1
HTTP_CONTENT hdr_val(content-length) gt 0 match an existing content-length
HTTP_URL_ABS url_reg ^[^/:]*:// match absolute URL with scheme
HTTP_URL_SLASH url_beg / match URL beginning with “/”
HTTP_URL_STAR url * match URL equal to “*”
LOCALHOST src 127.0.0.1/8 match connection from local host
METH_CONNECT method CONNECT match HTTP CONNECT method
METH_GET method GET HEAD match HTTP GET or HEAD method
METH_HEAD method HEAD match HTTP HEAD method
METH_OPTIONS method OPTIONS match HTTP OPTIONS method
METH_POST method POST match HTTP POST method
METH_TRACE method TRACE match HTTP TRACE method
RDP_COOKIE req_rdp_cookie_cnt gt 0 match presence of an RDP cookie
REQ_CONTENT req_len gt 0 match data in the request buffer
TRUE always_true always match
WAIT_END wait_end wait for end of content analysis

HAProxy：global, proxies（fronted, backend, listen, defaults）
balance：
roundrobin, static-rr
leastconn
first
source
hdr(<name>)
uri (hash-type)
url_param

Nginx调度算法： ip_hash, hash, leastconn, 
lvs调度算法：     rr/wrr/sh/dh, lc/wlc/sed/nq/lblc/lblcr

基于ACL的动静分离示例：
frontend  web *:80
acl url_static       path_beg       -i  /static /images /javascript /stylesheets
acl url_static       path_end       -i  .jpg .gif .png .css .js .html .txt .htm

use_backend staticsrvs          if url_static
default_backend             appsrvs

backend staticsrvs
balance     roundrobin
server      stcsrv1 172.16.100.6:80 check

backend appsrvs
balance     roundrobin
server  app1 172.16.100.7:80 check
server  app1 172.16.100.7:8080 check

listen stats
bind :9091
stats enable
stats auth admin:admin
stats admin if TRUE

配置HAProxy支持https协议： 
1 支持ssl会话；
bind *:443 ssl crt /PATH/TO/SOME_PEM_FILE

crt后的证书文件要求PEM格式，且同时包含证书和与之匹配的所有私钥；

cat  demo.crt demo.key > demo.pem 

2 把80端口的请求重向定443；
bind *:80
redirect scheme https if !{ ssl_fc }

3 如何向后端传递用户请求的协议和端口
http_request set-header X-Forwarded-Port %[dst_port]
http_request add-header X-Forwared-Proto https if { ssl_fc }