如何配置Apache作为j2ee服务器的代理（负载均衡器）？

Question

I have apache web server installed as frontend and I have j2ee SAP Netweaver Application Server installed in Intranet server. How can I configure apache to forward requests and response to/from j2ee app server. for example, external apache server's ip is 9.20.1.1:80. internal sap server's address is 192.168.0.1/sap/bc/gui/sap/its/webgui?sap_client=200 I want access to my sap app server for example 9.20.1.1/sapserver/sap/bc/gui/sap/its/webgui?sap_client=200

Answer 1

You mentioned load balancing- so presumably you want to be able to add more Application Servers that are served through a single address. I hope they are stateless or storing session information in a database. You can use Apache to serve as a reverse proxy load balancer with mod_proxy_balancer . Docs are here .

Here's an example of what to add to your httpd.conf from this link .

 <Proxy balancer://myclustername>
  # cluster member 1
  BalancerMember http://192.168.0.1:3000 
  BalancerMember http://192.168.0.1:3001

  # cluster member 2, the fastest machine so double the load
  BalancerMember http://192.168.0.11:3000 loadfactor=2
  BalancerMember http://192.168.0.11:3001 loadfactor=2

  # cluster member 3
  BalancerMember http://192.168.0.12:3000
  BalancerMember http://192.168.0.12:3001

  # cluster member 4
  BalancerMember http://192.168.0.13:3000
  BalancerMember http://192.168.0.13:3001
</Proxy>

<VirtualHost *:80>
  ServerAdmin info@meinprof.de
  ServerName www.meinprof.de
  ServerAlias meinprof.de
  ProxyPass / balancer://meinprofcluster/
  ProxyPassReverse / balancer://meinprofcluster/
  ErrorLog /var/log/www/www.meinprof.de/apache_error_log
  CustomLog /var/log/www/www.meinprof.de/apache_access_log combined
</VirtualHost>

Answer 2

This is often mistakenly referred to as a reverse proxy. If you use a search engine to find "reverse proxy apache" you will get many good results.

The quick answer is to add something like this to your apache.conf

ProxyPass /sap/ 192.168.0.1/sap/

< Location /sap/ >

  ProxyPassReverse /sap/ 

< /Location >

See also the modrewrite rools and the [P] option.

Answer 3

Assuming you have mod_proxy enabled, add to you're sites-available:

   ProxyRequests Off
   <Location "/sapserver">
        ProxyPass http://192.168.0.1
        ProxyPassReverse http://192.168.0.1
   </Location>

Be careful though as this does expose your internal site to the entire internet.