Bug 916387

Summary: mod_cluster 1.2.3.Final with httpd 2.2.15-15 generates confusing warning about version mismatch
Product: [JBoss] JBoss Enterprise Application Platform 6 Reporter: Ian Walker <ian.walker>
Component: mod_clusterAssignee: Jean-frederic Clere <jclere>
Status: CLOSED NOTABUG QA Contact:
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Version: 6.0.1   
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Hardware: Unspecified   
OS: Linux   
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Last Closed: 2013-05-30 14:20:27 UTC Type: Bug
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Description Ian Walker 2013-02-28 00:01:34 UTC 
Description of problem:
When using mod_cluster 1.2.3.Final with the version of httpd (2.2.15-15) that comes with RedHat Enterprise Linux 6.2, the following warning appears in the httpd error_log on startup:

  [warn] httpd version 2.2.15 mismatch detected

The warning message is somewhat confusing because 
  a) it does not tell you what component generated the warning
  b) it does not tell you what to do to fix it
  c) mod_cluster appears to work normally

Upgrading to a newer version of httpd (2.2.15-26 as of this writing) fixes the warning message.

I would suggest changing the message to something like "mod_proxy_cluster: httpd version x.x.x mismatch detected. Please upgrade to a newer version of httpd."

If the message cannot be changed, adding a note someplace about this warning would be helpful.


Version-Release number of selected component (if applicable):
RedHat Enterprise Linux 6.2
httpd 2.2.15-15
mod_cluster 1.2.3.Final


How reproducible:
Always


Steps to Reproduce:
1. Setup mod_cluster to work with httpd
2. Start httpd


Actual results:
"[warn] httpd version 2.2.15 mismatch detected" appears in the httpd error_log


Expected results:
No warning message


Additional info:
Problem appears to have been caused by httpd-2.2.15-proxy-failonstatus.patch which added errstatuses to the proxy_balancer struct in modules/proxy/mod_proxy.h.

httpd-2.2.15-15 does not have that field, which makes a sizeof() check in mod_proxy_cluster.c:proxy_cluster_post_config() fail, thus generating the warning.
Comment 1 Jean-frederic Clere 2013-02-28 07:55:09 UTC 
Stuff added to the structure should be a problem, the logic in mod_cluster takes that in account.
When the structure is too small "httpd version x.y.z too" will be displayed (and httpd won't start).
Comment 2 Jean-frederic Clere 2013-02-28 07:59:30 UTC 
I will changed the message to:
httpd version %d.%d.%d doesn't match version used by mod_proxy_cluster.c
which makes obvious that there is a glitch between to httpd version running and the version used to compile mod_cluster.
Comment 3 Ian Walker 2013-02-28 08:11:44 UTC 
(In reply to comment #2)
> I will changed the message to:
> httpd version %d.%d.%d doesn't match version used by mod_proxy_cluster.c
> which makes obvious that there is a glitch between to httpd version running
> and the version used to compile mod_cluster.

Thank you for considering a change to the message.

Unfortunately, "httpd version %d.%d.%d doesn't match version used by mod_proxy_cluster.c" does not tell one what version is used by mod_proxy_cluster.c, or what do do about the problem.

I think something like one of the following would be a bit clearer:

"httpd version %d.%d.%d does not match version used by mod_proxy_cluster.c. Try upgrading to a newer release of httpd."

This way the user knows that the warning was generated by mod_proxy_cluster.c and that they should upgrade their httpd.
Comment 4 Jean-frederic Clere 2013-02-28 09:04:13 UTC 
"Try upgrading to a newer release of httpd." that might not solve the problem if mod_cluster has been compiled with older version for example. I will add httpd version used when compiling mod_cluster to the message...
Comment 5 Ian Walker 2013-02-28 09:09:54 UTC 
If the release number appears in the version info, then that will be fine. 

I'm worried that the release number (as defined in the rpm) won't appear and you might get messages like "httpd version 2.2.15 doesn't match version used by mod_proxy_cluster.c (2.2.15)".
Comment 6 Jean-frederic Clere 2013-05-30 14:20:27 UTC 
It will be fixed in the next 1.3.x version.