I will change the JkLogLevel and post the results. I have a question though: Does prepost_timeout also detect if it received http code such as 503 from app server.
On Wed, Feb 25, 2009 at 9:05 AM, Rainer Jung <rainer.j...@kippdata.de> wrote: > On 25.02.2009 17:10, Mohit Anchlia wrote: >> >> you are right there is a mod-jk.conf. So given my workers.properties >> file what should I change so that mod_jk detects that app server is >> down before attempting to send the request. Shouldn't "retries" in >> workers.properties try to connect to some other app server instead. > > Just a wild guess: your prepost timeout of 5 milliseconds produces the error > messages you cited. First correct this timeout, then do another clean test > on your test system. You can even increase JkLogLevel to trace (not in > production) so we can see exactly what is going on. Do not send many > requests with JkLogLevel trace, just do a minimal test that shows the > problem. > > The early detection of a broken instance should be possible with your > configuration. > >> Here is mod-jk.conf >> >> # Where to find workers.properties >> JkWorkersFile conf/workers.properties >> >> # Where to put jk logs >> JkLogFile /var/log/apache2/mod_jk.log >> >> # Set the jk log level [debug/error/info] >> JkLogLevel error >> >> # Allow mod_jk worker status reports, with the URL of >> http://servername/JkStatus >> ## This is very helpful for monitoring purposes, but should be >> ## allowed from the local machine. >> <Location /JkStatus> >> Order deny,allow >> Deny from all >> Allow from localhost >> </Location> >> >> #JkMount /JkStatus status >> >> # Below line forward all requests to application server >> #JkMount /* local >> >> >> On Wed, Feb 25, 2009 at 2:55 AM, Rainer Jung<rainer.j...@kippdata.de> >> wrote: >>> >>> On 25.02.2009 02:47, Mohit Anchlia wrote: >>>> >>>> In httpd conf I just see JkMount and no other directive. I searched for >>>> Jk. >>> >>> There should be others as well, for instance JkWorkersFile to point to >>> your >>> workers.properties. The names of the directives are case insensitive, >>> they >>> can also be in files included to your main httpd configuration file via >>> include directives. >>> >>>> Here is workers.properties file: >>> >>> ... >>>> >>>> # appfe1 >>> >>> ... >>>> >>>> worker.appfe1.socket_timeout=5 >>> >>> I generally don't like socket_timeout. Others do :) >>> >>>> worker.appfe1.prepost_timeout=5 >>> >>> 5 milliseconds prepost timeout? You're kidding. I assume it should have >>> been >>> 5000. >>> >>>> worker.appfe1.recycle_timeout=900 >>> >>> This is deprecated. Use connection_pool_timeout instead. The value is OK, >>> you should set connectionTimeout on the Tomcat AJP connector to 900000 >>> then. >>> >>> Since you are using prefork MPM, you might want to set >>> connection_pool_minsize to 0 if you want to keep the number of >>> established >>> connections low. >>> >>> And the same for the other members of the load balancer. >>> >>>> On Tue, Feb 24, 2009 at 4:50 PM, Rainer Jung<rainer.j...@kippdata.de> >>>> wrote: >>>>> >>>>> On 25.02.2009 00:00, Mohit Anchlia wrote: >>>>>> >>>>>> Reposting: >>>>>> >>>>>> Apache Server - 2.2 >>>>>> Tomcat server 6 >>>>>> Jboss - 4.2 >>>>>> >>>>>> We have Web Servers talking to Jboss App Servers over mod_jk. When we >>>>>> do our patch or upgrade of software we do it in rolling fashion so >>>>>> that there is "0" customer impact. But it looks like mod_jk load >>>>>> balancer on Web server doesn't detect it as soon as Jboss App Server >>>>>> goes down. Our goal is to have 0 customer impact. So my question is >>>>>> what can we do to overcome this problem. Web Server sees Http Error >>>>>> Code 503. >>>>>> >>>>>> Information from log file: >>>>>> >>>>>> [Mon Feb 23 13:39:42.146 2009] [31682:4143745888] [error] >>>>>> ajp_connection_tcp_get_message::jk_ajp_common.c (966): (appfe4) can't >>>>>> receive the response message from tomcat, network problems or tomcat >>>>>> (10.10.81.89:8009) is down (errno=104) >>>>>> [Mon Feb 23 13:39:42.147 2009] [31682:4143745888] [error] >>>>>> ajp_service::jk_ajp_common.c (2097): (appfe4) Connecting to tomcat >>>>>> failed. Tomcat is probably not started or is listening on the wrong >>>>>> port >>>>> >>>>> This means that mod_jk detected that your backend is down and thus puts >>>>> it >>>>> into an error state. All following requests will no longer be sent to >>>>> this >>>>> backend. Once a minute it will send a request there and try, but as >>>>> long >>>>> as >>>>> it is down this test will not succeed and thus all requests will be >>>>> sent >>>>> to >>>>> other nodes. >>>>> >>>>> The first request that gets sent to the backend you stopped might get >>>>> an >>>>> error back. If you want to prevent that from happening, use >>>>> Cping/Cpong: >>>>> >>>>> http://tomcat.apache.org/connectors-doc/generic_howto/timeouts.html >>>>> >>>>> so we will detect the broken node before actually sending a request >>>>> there. >>>>> More details are not possible to give without your JK configuration (Jk >>>>> directive sin httpd configuration files, workers.properties and if used >>>>> uriworkermap.properties). >>>>> >>>>> The line number of the above message tells me you are using mod_jk >>>>> 1.2.25. >>>>> Although there's nothing wrong in principal with 1.2.25, we always try >>>>> to >>>>> improve and you might consider switching to 1.2.27. >>>>> >>>>> You should also increase your JkLogLevel to info. As long as only >>>>> occasional >>>>> info messages are in your log file everything is fine, but once error >>>>> messages show up, the additional info messages contain useful >>>>> formation. >>>>> >>>>> Regards, >>>>> >>>>> Rainer > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > > --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
