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Posted to users@tomcat.apache.org by János Löbb <ja...@yale.edu> on 2011/04/11 18:45:57 UTC
[Cluster] context question
Hi,
/Tomcat 7.0.10, OSX 10.6.5, jk 1.2.31, and httpd 2.2.17/
Without any explicit parameters in server.xml, just by setting the jvmRoute attribute in the Engine element and enabling Clustering, session failover worked if I shut down one or the other tomcat instance or the one httpd that was not the reverse proxy.
However when I just stopped the example webapp in one tomcat, the session did not failover and I received a 404 http error instead of the expected session page from the other tomcat.
Based upon the instructions found in the book: http://proquest.safaribooksonline.com/9780596101060/tomcat_6_clustering_implementation?sessionid=&reader=html&imagepage=
explicitely:
<nyissz>
You'll also need to add distributed="true" to the webapp's <Context> element. If there is no <Context> element declared for it anywhere, you will need to create one. You can create one by making a newCATALINA_HOME/conf/[EngineName]/[HostName]/examples.xml context XML fragment file or by adding one to server.xml.
<nyassz>
my thought was that the ReplicatedContect was not initiated. Well, I already learned that I should not add any context into server.xml and there is nothing in the
bml0066:local administrator$ ls -l tomcat1/conf/Catalina/localhost/
bml0066:local administrator$
directory, so I created a META-INF directory inside the examples directory and placed a context.xml there with the following content:
bml0066:local administrator$ cat tomcat1/webapps/examples/META-INF/context.xml
<?xml version="1.0" encoding="UTF-8"?>
<Context className="org.apache.catalina.ha.context.ReplicatedContext" distributed="true" >
</Context>
I did it on both tomcats and bounced them. Now when I look the log, I see the following warning just after restart:
INFO: Deploying web application directory examples
Apr 11, 2011 12:00:28 PM org.apache.catalina.startup.SetContextPropertiesRule begin
WARNING: [SetContextPropertiesRule]{Context} Setting property 'distributed' to 'true' did not find a matching property.
Apr 11, 2011 12:00:28 PM org.apache.catalina.tribes.tipis.AbstractReplicatedMap init
INFO: Initializing AbstractReplicatedMap with context name:/examples
Apr 11, 2011 12:00:28 PM org.apache.catalina.core.ApplicationContext log
INFO: ContextListener: contextInitialized()
Apr 11, 2011 12:00:28 PM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: contextInitialized()
So the first question is, should I use the distributed="true" property here ? Is the book right ? I think it is from 2007. I already have the <distributable/> tag in the webapp's web.xml.
The second question is what to do to avoid the 404 message and fail the session over instead of it, when I just stop the webapp on the tomcat instance? By default I am using sticky sessions.
<nyissz>
bml0066:local administrator$ cat apache2/conf/workers.properties
worker.list = lb,jkstatus
worker.lb.type=lb
worker.lb.balance_workers=tomcat1,tomcat3
#,tomcat2,tomcat4
worker.lb.sticky_session = True
worker.lb.sticky_session_force = False
worker.jkstatus.type=status
worker.tomcat1.type = ajp13
worker.tomcat1.host = bml0066.yalepath.org
worker.tomcat1.port = 8109
worker.tomcat1.lbfactor = 1
worker.tomcat1.redirect=tomcat3
#worker.tomcat2.type = ajp13
#worker.tomcat2.host = bml0066.yalepath.org
#worker.tomcat2.port = 8209
#worker.tomcat2.lbfactor = 1
#worker.tomcat2.redirect=tomcat4
worker.tomcat3.type = ajp13
worker.tomcat3.host = bml0065.yalepath.org
worker.tomcat3.port = 8309
worker.tomcat3.lbfactor = 1
worker.tomcat3.redirect=tomcat1
#worker.tomcat4.type = ajp13
#worker.tomcat4.host = bml0065.yalepath.org
#worker.tomcat4.port = 8409
#worker.tomcat4.lbfactor = 1
#worker.tomcat4.redirect=tomcat2
<nyassz>
Thanks ahead,
János
Re: [Cluster] context question
Posted by Christopher Schultz <ch...@christopherschultz.net>.
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Hash: SHA1
János,
On 4/11/2011 12:45 PM, János Löbb wrote:
> bml0066:local administrator$ ls -l tomcat1/conf/Catalina/localhost/
> bml0066:local administrator$
>
> directory, so I created a META-INF directory inside the examples directory and placed a context.xml there
You have confused things: META-INF/context.xml goes into your WAR file
(or exploded WAR webapp directory). If you want to use
tomcat1/conf/Catalina/localhost/, you'll want the file to be called
tomcat1/conf/Catalina/localhost/examples.xml
> with the following content:
>
> bml0066:local administrator$ cat tomcat1/webapps/examples/META-INF/context.xml
> <?xml version="1.0" encoding="UTF-8"?>
> <Context className="org.apache.catalina.ha.context.ReplicatedContext" distributed="true" >
> </Context>
Specifying the "className" for the <Context> shouldn't be necessary.
There is no "distributed" attribute in the <Context> element.
You should be configuring <distributed/> in web.xml, not in context.xml.
http://tomcat.apache.org/tomcat-7.0-doc/cluster-howto.html
> So the first question is, should I use the distributed="true" property here ? Is the book right ?
That book was published before TC 7 was available, so some things may
have changed.
> I think it is from 2007. I already have the <distributable/> tag in the webapp's web.xml.
That should be all you need, plus a <Cluster> configuration in
server.xml. Read the Cluster HOWTO document above.
> The second question is what to do to avoid the 404 message and fail the session over instead of it, when I just stop the webapp on the tomcat instance? By default I am using sticky sessions.
<distributable> + clustering should result in session fail-over with our
without sticky sessions. One could argue that session session stickiness
is not necessary if you are fully replicating your sessions across the
cluster -- though you may have some transient state that needs to be
re-built on a fail-over target that might use more memory or resources
in which case stickiness is useful.
- -chris
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Re: [Cluster] context question
Posted by János Löbb <ja...@yale.edu>.
On Apr 11, 2011, at 12:45 PM, János Löbb wrote:
> Hi,
>
> /Tomcat 7.0.10, OSX 10.6.5, jk 1.2.31, and httpd 2.2.17/
>
> Without any explicit parameters in server.xml, just by setting the jvmRoute attribute in the Engine element and enabling Clustering, session failover worked if I shut down one or the other tomcat instance or the one httpd that was not the reverse proxy.
>
> However when I just stopped the example webapp in one tomcat, the session did not failover and I received a 404 http error instead of the expected session page from the other tomcat.
>
> Based upon the instructions found in the book: http://proquest.safaribooksonline.com/9780596101060/tomcat_6_clustering_implementation?sessionid=&reader=html&imagepage=
>
> explicitely:
>
> <nyissz>
> You'll also need to add distributed="true" to the webapp's <Context> element. If there is no <Context> element declared for it anywhere, you will need to create one. You can create one by making a newCATALINA_HOME/conf/[EngineName]/[HostName]/examples.xml context XML fragment file or by adding one to server.xml.
> <nyassz>
>
> my thought was that the ReplicatedContect was not initiated. Well, I already learned that I should not add any context into server.xml and there is nothing in the
>
> bml0066:local administrator$ ls -l tomcat1/conf/Catalina/localhost/
> bml0066:local administrator$
>
> directory, so I created a META-INF directory inside the examples directory and placed a context.xml there with the following content:
>
> bml0066:local administrator$ cat tomcat1/webapps/examples/META-INF/context.xml
> <?xml version="1.0" encoding="UTF-8"?>
> <Context className="org.apache.catalina.ha.context.ReplicatedContext" distributed="true" >
> </Context>
>
> I did it on both tomcats and bounced them. Now when I look the log, I see the following warning just after restart:
>
> INFO: Deploying web application directory examples
> Apr 11, 2011 12:00:28 PM org.apache.catalina.startup.SetContextPropertiesRule begin
> WARNING: [SetContextPropertiesRule]{Context} Setting property 'distributed' to 'true' did not find a matching property.
> Apr 11, 2011 12:00:28 PM org.apache.catalina.tribes.tipis.AbstractReplicatedMap init
> INFO: Initializing AbstractReplicatedMap with context name:/examples
> Apr 11, 2011 12:00:28 PM org.apache.catalina.core.ApplicationContext log
> INFO: ContextListener: contextInitialized()
> Apr 11, 2011 12:00:28 PM org.apache.catalina.core.ApplicationContext log
> INFO: SessionListener: contextInitialized()
>
>
> So the first question is, should I use the distributed="true" property here ? Is the book right ? I think it is from 2007. I already have the <distributable/> tag in the webapp's web.xml.
>
> The second question is what to do to avoid the 404 message and fail the session over instead of it, when I just stop the webapp on the tomcat instance? By default I am using sticky sessions.
>
> <nyissz>
> bml0066:local administrator$ cat apache2/conf/workers.properties
> worker.list = lb,jkstatus
>
> worker.lb.type=lb
> worker.lb.balance_workers=tomcat1,tomcat3
> #,tomcat2,tomcat4
> worker.lb.sticky_session = True
> worker.lb.sticky_session_force = False
>
> worker.jkstatus.type=status
>
> worker.tomcat1.type = ajp13
> worker.tomcat1.host = bml0066.yalepath.org
> worker.tomcat1.port = 8109
> worker.tomcat1.lbfactor = 1
> worker.tomcat1.redirect=tomcat3
>
> #worker.tomcat2.type = ajp13
> #worker.tomcat2.host = bml0066.yalepath.org
> #worker.tomcat2.port = 8209
> #worker.tomcat2.lbfactor = 1
> #worker.tomcat2.redirect=tomcat4
>
> worker.tomcat3.type = ajp13
> worker.tomcat3.host = bml0065.yalepath.org
> worker.tomcat3.port = 8309
> worker.tomcat3.lbfactor = 1
> worker.tomcat3.redirect=tomcat1
>
> #worker.tomcat4.type = ajp13
> #worker.tomcat4.host = bml0065.yalepath.org
> #worker.tomcat4.port = 8409
> #worker.tomcat4.lbfactor = 1
> #worker.tomcat4.redirect=tomcat2
>
> <nyassz>
>
> Thanks ahead,
>
> János
>
>
>
Testing out he examples webapp I found this in the log of that tomcat where I shut down the webapp:
<nyissz>
INFO: Server startup in 6625 ms
Apr 11, 2011 12:43:59 PM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: sessionCreated('1CAEC5FA2D27A7410C819A8BBF9E7F77.tomcat1')
Apr 11, 2011 12:47:23 PM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: sessionCreated('69EB2E77CE0D912F8584E60B4CB828D7.tomcat3')
Apr 11, 2011 12:47:46 PM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: attributeAdded('69EB2E77CE0D912F8584E60B4CB828D7.tomcat3', 's1', 't3')
Apr 11, 2011 12:48:40 PM org.apache.catalina.core.ApplicationContext log
INFO: HTMLManager: init: Associated with Deployer 'Catalina:type=Deployer,host=localhost'
Apr 11, 2011 12:48:40 PM org.apache.catalina.core.ApplicationContext log
INFO: HTMLManager: init: Global resources are available
Apr 11, 2011 12:48:54 PM org.apache.catalina.core.ApplicationContext log
INFO: HTMLManager: list: Listing contexts for virtual host 'localhost'
Apr 11, 2011 12:49:01 PM org.apache.catalina.core.ApplicationContext log
INFO: HTMLManager: stop: Stopping web application '/examples'
Apr 11, 2011 12:49:01 PM org.apache.catalina.ha.session.DeltaManager stopInternal
INFO: Manager [localhost#/examples] expiring sessions upon shutdown
Apr 11, 2011 12:49:01 PM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: sessionDestroyed('69EB2E77CE0D912F8584E60B4CB828D7.tomcat3')
Apr 11, 2011 12:49:01 PM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: attributeRemoved('69EB2E77CE0D912F8584E60B4CB828D7.tomcat3', 's1', 't3')
Apr 11, 2011 12:49:01 PM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: sessionDestroyed('1CAEC5FA2D27A7410C819A8BBF9E7F77.tomcat1')
Apr 11, 2011 12:49:01 PM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: contextDestroyed()
Apr 11, 2011 12:49:01 PM org.apache.catalina.core.ApplicationContext log
INFO: ContextListener: contextDestroyed()
Apr 11, 2011 12:49:01 PM org.apache.catalina.core.ApplicationContext log
SEVERE: HTMLManager: ManagerServlet.stop[/examples]
java.lang.NullPointerException
at org.apache.catalina.ha.context.ReplicatedContext.stopInternal(ReplicatedContext.java:86)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.manager.ManagerServlet.stop(ManagerServlet.java:1273)
at org.apache.catalina.manager.HTMLManagerServlet.stop(HTMLManagerServlet.java:754)
at org.apache.catalina.manager.HTMLManagerServlet.doPost(HTMLManagerServlet.java:222)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.filters.CsrfPreventionFilter.doFilter(CsrfPreventionFilter.java:186)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:591)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.ha.tcp.ReplicationValve.invoke(ReplicationValve.java:333)
at org.apache.catalina.ha.session.JvmRouteBinderValve.invoke(JvmRouteBinderValve.java:218)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:394)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:680)
Apr 11, 2011 12:49:01 PM org.apache.catalina.core.ApplicationContext log
INFO: HTMLManager: list: Listing contexts for virtual host 'localhost'
Apr 11, 2011 12:49:48 PM org.apache.catalina.core.ApplicationContext log
INFO: HTMLManager: start: Starting web application '/examples'
Apr 11, 2011 12:49:48 PM org.apache.catalina.core.ApplicationContext log
SEVERE: FAIL - Application at context path /examples could not be started
org.apache.catalina.LifecycleException: An invalid Lifecycle transition was attempted ([before_start]) for component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/examples]] in state [STOPPING]
at org.apache.catalina.util.LifecycleBase.invalidTransition(LifecycleBase.java:386)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:139)
at org.apache.catalina.manager.ManagerServlet.start(ManagerServlet.java:1223)
at org.apache.catalina.manager.HTMLManagerServlet.start(HTMLManagerServlet.java:735)
at org.apache.catalina.manager.HTMLManagerServlet.doPost(HTMLManagerServlet.java:220)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.filters.CsrfPreventionFilter.doFilter(CsrfPreventionFilter.java:186)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:591)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.ha.tcp.ReplicationValve.invoke(ReplicationValve.java:333)
at org.apache.catalina.ha.session.JvmRouteBinderValve.invoke(JvmRouteBinderValve.java:218)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:394)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:680)
Apr 11, 2011 12:49:48 PM org.apache.catalina.core.ApplicationContext log
INFO: HTMLManager: list: Listing contexts for virtual host 'localhost'
<nyassz>
so, tomcat did go into a state that does not allow the app be started correctly via the manager webapp. When I try to access it via a browser I receive:
<nyissz>
HTTP Status 404 - /examples/servlets/servlet/SessionExample
type Status report
message /examples/servlets/servlet/SessionExample
description The requested resource (/examples/servlets/servlet/SessionExample) is not available.
Apache Tomcat/7.0.10
<nyassz>
I have to restart the tomcat instance and all the other webapps with it to get it out from that stage producing the 404 message.
Is there a better way ?
Thanks ahead,
János