>-----Original Message----- >From: Rainer Jung [mailto:rainer.j...@kippdata.de] >Sent: Wednesday, July 25, 2012 5:00 AM >To: users@httpd.apache.org >Subject: Re: [users@httpd] Intermittent mod_proxy_ajp error - APR does not >understand this error code: proxy: dialog > >On 23.07.2012 20:36, Carlucci, Tony wrote: >> Hello, I’ve been trying to track down an intermittent problem with a >> Java web application that is running on tcServer fronted by Apache HTTP >> Server. We get intermittent “Server Unavailable / HTTP 500” errors, >> and when we do see them, there is the same set of log statements written >> to the Apache HTTP Server error log: >> >> [Mon Jul 23 10:03:15 2012] [error] (70014)End of file found: >> ajp_ilink_receive() can't receive header >> >> [Mon Jul 23 10:03:15 2012] [error] ajp_read_header: ajp_ilink_receive failed >> >> [Mon Jul 23 10:03:15 2012] [error] (120006)APR does not understand this >> error code: proxy: dialog to 127.0.0.1:7071 (127.0.0.1) failed >> >> We are not seeing any error messages in the tcServer logs. >> >> I believe the issue is with the mod_proxy_ajp module but it’s been very >> difficult tracking down what exactly the problem is. What’s >> interesting is that this Apache / tcServer configuration is used with >> other applications that work just fine and never have the intermittent >> 500 error. We also can run our application strictly in Tomcat (no >> Apache front) without any intermittent errors. >> >> We haven’t ruled out that there could be something in our Java >> application code that is causing this, in combination with the >> mod_proxy_ajp module, but we have hit a wall as to what this issue could >> be. Has anyone else experienced a similar intermittent issue combined >> with the above error messages? Below is a copy of the error log and >> some configuration settings. > >You might want to check the following discussion thread: > > http://marc.info/?t=123905265500007&r=1&w=2 > >To actually narrow down the cause I would: > >- use ping as mentioned in the thread >- check whether the timeout you have set on the Tomcat connector is >roughly the same as used by mod_proxy_ajp >- check whether it looks like happening mostly for the same URL, then it >is more likely a servlet issue >- if it happens often enough sniff the traffic between Apache and Tomcat >and then check the packet details for one of the broken requests. For >this to work you might need to move Tomcat away from localhost. >
Thanks for the suggestions Rainer, I'll give these a try. Tony >Regards, > >Rainer > >--------------------------------------------------------------------- >To unsubscribe, e-mail: users-unsubscr...@httpd.apache.org >For additional commands, e-mail: users-h...@httpd.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@httpd.apache.org For additional commands, e-mail: users-h...@httpd.apache.org
