企业级反向代理 Haproxy--调度算法（四）

5 HAProxy 调度算法

HAProxy通过固定参数 balance 指明对后端服务器的调度算法，该参数可以配置在listen或backend选 项中。

HAProxy的调度算法分为静态和动态调度算法，但是有些算法可以根据不同的参数实现静态和动态算法 相互转换。

官方文档：http://docs.haproxy.org/3.0/configuration.html#4-balance

5.1 Socat 工具

对服务器动态权重和其它状态可以利用 socat 工具进行调整，Socat 是 Linux 下的一个多功能的网络工 具，名字来由是Socket CAT，相当于netCAT的增强版.Socat 的主要特点就是在两个数据流之间建立双向 通道，且支持众多协议和链接方式。如 IP、TCP、 UDP、IPv6、Socket文件等

范例：利用工具socat对服务器动态权重调整

# 安装socat
root@ubutun2204-1:~# apt update && apt -y install socat

#查看帮助
root@ubutun2204-1:~# echo "help" | socat stdio /var/lib/haproxy/haproxy.sock
The following commands are valid at this level:
  abort ssl ca-file <cafile>              : abort a transaction for a CA file
  abort ssl cert <certfile>               : abort a transaction for a certificate file
  abort ssl crl-file <crlfile>            : abort a transaction for a CRL file
  add acl [@<ver>] <acl> <pattern>        : add an acl entry
  add map [@<ver>] <map> <key> <val>      : add a map entry (payload supported instead of key/val)
  add server <bk>/<srv>                   : create a new server
  add ssl ca-file <cafile> <payload>      : add a certificate into the CA file
  add ssl crt-list <list> <cert> [opts]*  : add to crt-list file <list> a line <cert> or a payload
  clear acl [@<ver>] <acl>                : clear the contents of this acl
  clear counters [all]                    : clear max statistics counters (or all counters)
  clear map [@<ver>] <map>                : clear the contents of this map
  clear table <table> [<filter>]*         : remove an entry from a table (filter: data/key)
  commit acl @<ver> <acl>                 : commit the ACL at this version
  commit map @<ver> <map>                 : commit the map at this version
  commit ssl ca-file <cafile>             : commit a CA file
  commit ssl cert <certfile>              : commit a certificate file
  commit ssl crl-file <crlfile>           : commit a CRL file
  debug dev hash   [msg]                  : return msg hashed if anon is set
  del acl <acl> [<key>|#<ref>]            : delete acl entries matching <key>
  del map <map> [<key>|#<ref>]            : delete map entries matching <key>
  del server <bk>/<srv>                   : remove a dynamically added server
  del ssl ca-file <cafile>                : delete an unused CA file
  del ssl cert <certfile>                 : delete an unused certificate file
  del ssl crl-file <crlfile>              : delete an unused CRL file
  del ssl crt-list <list> <cert[:line]>   : delete a line <cert> from crt-list file <list>
  disable agent                           : disable agent checks
  disable dynamic-cookie backend <bk>     : disable dynamic cookies on a specific backend
  disable frontend <frontend>             : temporarily disable specific frontend
  disable health                          : disable health checks
  disable server (DEPRECATED)             : disable a server for maintenance (use 'set server' instead) #禁用服务器
  dump stats-file                         : dump stats for restore
  enable agent                            : enable agent checks
  enable dynamic-cookie backend <bk>      : enable dynamic cookies on a specific backend
  enable frontend <frontend>              : re-enable specific frontend
  enable health                           :