6 Replies Latest reply on Feb 5, 2007 8:10 AM by shi lei

    Open connections with Apache 2.2+mod_proxy_ajp+JBoss/Tomcat

    Stephen Keumurian Newbie

      Hello,

      I've been trying to track down a problem on our server for a while now and thought I'd check in here to see if anyone has a solution. I have Apache 2.2.2 setup as a front end for JBoss 4.0.2 on the same server. I have a rather long list of named virtual hosts being served on this one system. I'm using mod_proxy_ajp to route traffic to multiple web applications on the server. I'm running into a situation where the number of connections from Apache to the Tomcat AJP connector (localhost:8009) is forever growing and eventually people are blocked from accessing the server. The connections are left in the "ESTABLISHED" state as viewed by netstat.

      tcp4 0 0 localhost.8009 localhost.49163 ESTABLISHED
      tcp4 0 0 localhost.49163 localhost.8009 ESTABLISHED
      


      I've tried using Apache with the worker MPM as well as the pre-fork MPM and the problem seems to occur with both, but becomes a problem a lot sooner with the pre-fork MPM.

      I tried editing jboss-4.0.2/server/default/deploy/jbossweb-tomcat55.sar/server.xml to include a connectionTimeout value of 20000 milliseconds. This timeout works, but then instead of the connections being left in the "ESTABLISHED" state they are now left as "CLOSE_WAIT." I've tried changing various values on the Apache side, such as specifying smax, ttl, etc. to no avail.

      I'm defining the proxy to my application like this:

      <Location /cdf>
       ProxyPass ajp://localhost:8009/cdf smax=30 ttl=30 retry=1
       ProxyPassReverse ajp://localhost:8009/cdf
      </Location>
      


      This is included in each named virtual host that needs access to the application. Other virtual hosts have their own Location entries that proxy pass to other applications.

      My http-mpm.conf is setup like this for the worker MPM:
      <IfModule mpm_worker_module>
       StartServers 2
       MaxClients 300
       MinSpareThreads 25
       MaxSpareThreads 300
       ThreadsPerChild 25
       MaxRequestsPerChild 0
      </IfModule>
      


      and like this for the prefork:

      <IfModule mpm_prefork_module>
       StartServers 15
       MinSpareServers 51
       MaxSpareServers 65
       MaxClients 500
       MaxRequestsPerChild 0
      </IfModule>
      


      I have a test server that I has a simpler version of the same setup on (no named virtual hosts) and I'm seeing this behavior there as well. I've tried creating a test application that only includes a basic index.html and it appears to behave the same way. Am I missing something? Am I using mod_proxy_ajp incorrectly?

      Thanks,
      Stephen