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Subject Apache / mod_jk / Jboss-tomcat weirdness
Date Fri, 08 Aug 2008 08:59:34 GMT
Hello everyone,

I previously asked this on the Apache users mailing list - but it occurred
to me that this list may be more appropriate)

I'm trying to figure out some weirdness in a fairly large web environment.

We're running a web environment using RHEL 4, Apache 2.0.52 with Worker
MPM, mod_jk 1.2.20 and jboss/tomcat application servers (Jboss 4 / tomcat55).
There's a firewall between our web and application servers, and I have
read about mod_jk and firewalls (i.e. socket_keepalive = 1).

A weird thing I see is that sometimes, the apache server status page
displays requests/threads in the "W" (sending reply) state up to Apache
timeout, while the Jboss Jk status shows no threads for that client in the
"Service" state.

In fact, most of the "busy" threads are reported to be in the "Keepalive"
state - I presume due to the use of  socket_keepalive = 1 in

This means my problem kind of resembles the one described at, where Apache
threads get stuck in the "W" state instead of being closed (as to be
expected) - as if client-apache and apache/mod_jk - backend appserver
connections are not "detached".

I'm wondering what can cause this behaviour, as my has
the following:


When socket_keepalive=1, how long does a connection exist between mod_jk
and the application server? How can I control it?

Do I need to use cache_Size and cache_timeout in I
don't quite get their explanation - but cache_timeout does talk about
reducing the number of threads on the backend.

It seems the poster pointed to by the link I gave solved his problem by
implementing the mod_jk firewall howto in the end (i.e. set
socket_keepalive to 1) - but I am still having similar issues it seems.
Does this ring a bell with anyone?

Kind regards,

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