See Thread at: http://www.techienuggets.com/Detail?tx=25608 Posted on behalf of
a User
Hallo to all,
After long unsuccessful research i hope someone can give me a hint to the
following problems.
Our Apache-mod_jk-Tomcat Infrastructur was running without Problems for about
one year-than since two month mod_jk errors occurs.
We upgraded the mod_jk Version, made improvements in the worker.properties -
the problems changed and get less but sometimes they appear further on.
It seems that the mod_jk worker loose the connection to their
Tomcat-Backendserver - there are messages in the mod_jk log Files which points
in this direction. Normally this seems not to be a big problem - but under
certain conditions (which ?) the worker goes to an error state and cannot
recover itself- must be done manually.
Problem 1: The Tomcats are reachable - unknown why the workers think the server
is dead ?
Problem 2: I have no idea why the worker goes to an error state and cannot
recover.
Problem3: I miss explanations of logged messages - i read the messages - but
cannot match them to the situation - when does a worker post this messages
[Wed Feb 20 10:04:01.889 2008] [19237:3086010048] [info] jk_handler::mod_jk.c
(2270): Aborting connection for worker=ajp_ggi
[Wed Feb 20 10:04:39.799 2008] [19294:3086010048] [error]
ajp_get_reply::jk_ajp_common.c (1623): (INETP1011) Timeout with waiting reply
from tomcat. Tomcat is down, stopped or network problems (errno=110)
[Wed Feb 20 10:04:39.799 2008] [19294:3086010048] [error]
ajp_service::jk_ajp_common.c (2034): (INETP1011) receiving reply from tomcat
failed with out recovery in send loop attempt=0
[Wed Feb 20 10:04:41.799 2008] [19294:3086010048] [error]
service::jk_lb_worker.c (1105): unrecoverable error 504, request failed. Tomcat
failed in the middle of request, we can't recover to another instance.
-> Which Timeout - how does mod_jk think Tomcat is down ? Where can i found
details to errno=110 ?...
-> receiving reply from tomcat failed with out recovery in send loop attempt=0
- ? with out recovery in send loop - means?
-> unrecoverable error 504 - details to this error ?
Ok - i turn the logging level to debug - the course of events get more clear -
but also more questions appear - there are socket numbers - which sockets -
what are these numbers e.g will be shutting down socket 35 for worker INETP1021
- The sockets are good for ? - how many are there/per worker ? can i configure
them ?
=> Generally -How can i solve such problems - i tried to look into the mod_jk
code - searching for error codes, error messages - but cannot find some
relevant informations, - i am studying the log Files - but don't find out what
really happens.
So - maybe someone has an idea why the worker think that the corresponding
Tomcat is dead, and why he will not recover by itself. !
And i am also searching for tips how i can help myself - and where to find
something about the error codes, messages,..in mod_jk
thanks for your attention
Best
ahmed musa (writing from vienna)
Current Infrastructur
We have 3 Apache Webserver (2.2.6) -based on CentOS release 4.3 /Kernelversion
2.6.9-34
In front of the Webserver there are two (two Locations) HW-Loadbalancer (but
they have no role in this story)
The Webservers are hosted at our ISP.
The Webserver balance the requests via mod_jk (Version 1.2.25) for approx. 10
Webapps to 18 Backend-Tomcatserver (Bladeserver - because of underlying
Application-Parts the OS is Windows 2003 Server - a long story not worth to
explain :-) ). The Tomcatserver gain Data via Requests against DB2
Server/DB2-Databases on the Mainframe. The Tomcatserver are Inhouse -and were
rebooted nightly because of automated Deployment processes.
Between the Webserver and the Tomcatserver is a Checkpoint Firewall.
All webapps are deployed on all Tomcats - only mod_jk manages the requests to
certain Tomcat- instances.
(on one Bladeserver there are two identically Tomcat Instances running).
Versions: Tomcat - 5.5.17_11, JDK 1.5.0_11-b03. The requests against the public
Website(s) are normal short living requests - not many - The most Webapps
(Portals) need a login, have a strong focus on business
logic - so the instances are big (many MBs in RAM), the sessions are sticky and
the session timeout is 20 minutes. But there are also less requests. To the
User requests - Monitoring requests from our ISP are added.
The Problems appears at Servers/Portals which very less Userrequests.
worker.properties
worker.list=ajp_bam,ajp_ggi,ajp_ad,ajp_svp,.......,jkstatus
worker.template.type=ajp13
worker.template.lbfactor=5
worker.template.socket_keepalive=1
worker.template.connect_timeout=7000
worker.template.prepost_timeout=5000
worker.template.reply_timeout=120000
worker.template.retries=6
worker.template.activation=Active
worker.template.recovery_options=7
worker.lbtemplate.type=lb
worker.lbtemplate.max_reply_timeouts=6
worker.lbtemplate.method=Session
#Produktions Worker
# AS-INETP101 - 106 - 6/6 GGI
worker.INETP1011.host=AS-INETP101.AEAT.ALLIANZ.AT
worker.INETP1011.port=65001
worker.INETP1011.reference=worker.template
....many more of the same
then
worker.ajp_ad.reference=worker.lbtemplate
worker.ajp_ad.balance_workers=INETP1032,INETP1062
.... many more portals
at least jkstatus
The JKMount is very simple
JkMount /* ajp_ad --- for the other portals mostly the same
The Portals are Virtual Hosts on the Apache.
Tomcat - server.xml
example
<Connector port="65001" maxThreads="300" protocol="AJP/1.3" />
<Engine name="Catalina" jvmRoute="INETP5021" defaultHost="default">
......
<Host name="slfinsol.com" appBase="webapps" unpackWARs="true"
autoDeploy="false" deployOnStartup="false" xmlValidation="false"
xmlNamespaceAware="false">
<Alias>www.slfinsol.com</Alias>
<Alias>web1.slfinsol.com</Alias>
...
<Alias>testweb.slfinsol.com</Alias>
.....
<Valve className="org.apache.catalina.valves.AccessLogValve"
directory="logs" prefix="swl_access_log." suffix=".txt" pattern="common"
resolveHosts="false" />
<Valve
className="at.allianz.tomcat.valve.RequestTimeValve"/>
<Valve
className="at.allianz.tomcat.valve.WebcollaborationWorkaroundValve"/>
<Context path="" docBase="swl" />
<Context path="/monitor5" docBase="monitor" />
<Context path="/swl" docBase="swl" />
</Host>
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