基于HAproxy的 session同步实践

首先安装，启动，配置HAproxy的方法网上已经有很多的介绍，此处不再作过多阐述

推荐2个比较有用的安装配置资料：

安装说明

http://blog.chinaunix.net/uid-17291169-id-4744949.html

配置文件说明

http://www.linuxidc.com/Linux/2012-07/65350.htm

 

另附简单操作代码

重启 关闭 与 启动

 

service haproxy start/stop/restart

查询状态

 

 

service haproxy status

 

 

 

 

OK，前期工作准备完成，下面来描述一下测试环境

工程1：http://192.168.28.151:1199/TestHa/

工程2：http://192.168.28.151:2299/TestHa/

利用HaProxy做负载均衡，并且配置session同步

以下是HaProsy的配置文件

 

#---------------------------------------------------------------------
# Example configuration for a possible web application.  See the
# full configuration options online.
#
#   http://haproxy.1wt.eu/download/1.4/doc/configuration.txt
#
#---------------------------------------------------------------------

#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
    # to have these messages end up in /var/log/haproxy.log you will
    # need to:
    #
    # 1) configure syslog to accept network log events.  This is done
    #    by adding the '-r' option to the SYSLOGD_OPTIONS in
    #    /etc/sysconfig/syslog
    #
    # 2) configure local2 events to go to the /var/log/haproxy.log
    #   file. A line like the following can be added to
    #   /etc/sysconfig/syslog
    #
    #    local2.*                       /var/log/haproxy.log
    #
    log         127.0.0.1 local2

    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon

    # turn on stats unix socket
    stats socket /var/lib/haproxy/stats

#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------
defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s
    maxconn                 3000

#---------------------------------------------------------------------
# main frontend which proxys to the backends
#---------------------------------------------------------------------
#此处配置HAProxy的监听端口
frontend  main *:5000
    acl url_static       path_beg       -i /static /images /javascript /stylesheets
    acl url_static       path_end       -i .jpg .gif .png .css .js

    use_backend static          if url_static
    default_backend             app

#---------------------------------------------------------------------
# static backend for serving up images, stylesheets and such
#---------------------------------------------------------------------
backend static
    balance     roundrobin
    server      static 127.0.0.1:4331 check

#---------------------------------------------------------------------
# round robin balancing between the various backends
#---------------------------------------------------------------------
backend app
    appsession JSESSIONID len 64 timeout 5h request-learn  #必配
    server  app1 192.168.28.151:1199 cookie app1 check#必配
    server  app2 192.168.28.151:2299 cookie app2 check#必配
# option httpchk GET /index.html
listen status 192.168.28.151:8899
    stats enable
    stats uri /stats
    stats auth admin:123456
    stats admin if TRUE
    stats realm (Haproxy\ statistic)

 

配置完成后测试一下结果

访问 http://192.168.28.151:5000/TestHa/

可见此过程中的三次跳转，HaProxy已经根据sessionid将本次会话都分配给了同一台机器。

那么我们再换一个浏览器测试一下负载均衡

 

 新的浏览器建立的新的会话被负载到了另外一个端口上。

实验至此并未结束，实际上HAProxy为我们提供了3种方法来实现session共享

• 用户IP 识别  
• cookie 识别  
• session 识别  

个人觉得前两种比较有局限性，第一种根据ip来分配，在ip变动的时候将会失去这种session一致性。第二种方法将一个cookie头植入客户端，倘若客户端禁用cookie那么也无法实现

详细的关于这三种方法可以阅读

http://itindex.net/blog/2012/07/24/1343118758531.html