We have a developed an large scale application that is clustered
using WebLogic. I have been exploring getting the app clustered on Tomcat as
a learning experience and to possibly sway the management away from
WebLogic. I have Tomcat 5.0.19 set up with the latest production version of
Apache using mod_jk.
I have one Tomcat instance configured to use port 8080 and another
on 9090 on a RedHat 9.0 box. I am setting LD_ASSUME_KERNEL to 2.4. No error
messages are displayed during startup.
I have done enough testing to feel confident in the
Apache/jk_mod/tomcat configuration. For example, I can use Tomcat's included
SessionExample to go to host:8080 and enter a session variable, and when I
then go to host:9090 the variable is displayed along with the correct
session id. The session has .worker1 appended to the end of the string. I
can add variables and bounce back and forth (through apache, 8080, and 9090
url's) and all variables are displayed correctly with the same session id.
This indicates to me that the two clusters are aware of each other and are
passing session information back and forth. I can confirm this in the
catalina.out log.
In our app the web.xml contains the <distributable/> tag and both
Tomcat instances have the useDirtyFlag set to false.
Now, when I log into our app and start driving around I receive
several of the following exception:
Apr 14, 2004 10:15:29 AM org.apache.catalina.cluster.session.DeltaManager
messageReceived
SEVERE: Unable to receive message through TCP channel
java.lang.ClassNotFoundException:
com.mycompany.ourapp.common.model.ReturnPolicy
at
org.apache.catalina.loader.StandardClassLoader.loadClass(StandardClassLoader
.java:891)
at
org.apache.catalina.loader.StandardClassLoader.loadClass(StandardClassLoader
.java:756)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:219)
at
java.io.ObjectInputStream.resolveProxyClass(ObjectInputStream.java:630)
at
java.io.ObjectInputStream.readProxyDesc(ObjectInputStream.java:1469)
at
java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1432)
at
java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1626)
at
java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1274)
at
java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1845)
at
java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1769)
at
java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1646)
at
java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1274)
at
java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1845)
at
java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1769)
at
java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1646)
at
java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1274)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:324)
at
org.apache.catalina.cluster.session.DeltaRequest$AttributeInfo.readExternal(
DeltaRequest.java:335)
at
org.apache.catalina.cluster.session.DeltaRequest.readExternal(DeltaRequest.j
ava:247)
at
org.apache.catalina.cluster.session.DeltaManager.loadDeltaRequest(DeltaManag
er.java:420)
at
org.apache.catalina.cluster.session.DeltaManager.messageReceived(DeltaManage
r.java:921)
at
org.apache.catalina.cluster.session.DeltaManager.messageDataReceived(DeltaMa
nager.java:794)
at
org.apache.catalina.cluster.tcp.SimpleTcpCluster.messageDataReceived(SimpleT
cpCluster.java:561)
at
org.apache.catalina.cluster.io.ObjectReader.execute(ObjectReader.java:117)
at
org.apache.catalina.cluster.tcp.TcpReplicationThread.drainChannel(TcpReplica
tionThread.java:176)
at
org.apache.catalina.cluster.tcp.TcpReplicationThread.run(TcpReplicationThrea
d.java:114
I have looked in our deployed .war and that class does exist. There
appears to be no ryme or reason as to when the exception is thrown - it
seems random with no pattern. Can anyone give me more information on what
causes this exception? Any ideas?
Also, when I then shutdown an instance and click on a link within
the app (attempting to cause the Apache to swith over to another worker),
I'm logged out of the app and the following exception is thrown:
Apr 14, 2004 10:16:10 AM org.apache.catalina.cluster.session.DeltaSession
tellNew
SEVERE: Session event listener threw exception
java.lang.IllegalStateException: getAttribute: Session already invalidated
at
org.apache.catalina.cluster.session.DeltaSession.getAttribute(DeltaSession.j
ava:1054)
at
org.apache.catalina.cluster.session.DeltaSessionFacade.getAttribute(DeltaSes
sionFacade.java:157)
at com.mckesson.smo.app.SmoSession.get(SmoSession.java:41)
at
com.mckesson.smo.app.SmoSessionController.sessionCreated(SmoSessionControlle
r.java:98)
at
org.apache.catalina.cluster.session.DeltaSession.tellNew(DeltaSession.java:4
59)
at
org.apache.catalina.cluster.session.DeltaSession.setId(DeltaSession.java:431
)
at
org.apache.catalina.cluster.session.DeltaManager.createSession(DeltaManager.
java:377)
at
org.apache.catalina.cluster.session.DeltaManager.createSession(DeltaManager.
java:345)
at
org.apache.coyote.tomcat5.CoyoteRequest.doGetSession(CoyoteRequest.java:2285
)
at
org.apache.coyote.tomcat5.CoyoteRequest.getSession(CoyoteRequest.java:2127)
at
org.apache.coyote.tomcat5.CoyoteRequestFacade.getSession(CoyoteRequestFacade
.java:549)
at
org.apache.coyote.tomcat5.CoyoteRequestFacade.getSession(CoyoteRequestFacade
.java:554)
at
com.mckesson.smo.app.SmoApplicationFilter.doFilter(SmoApplicationFilter.java
:52)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application
FilterChain.java:233)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh
ain.java:204)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.ja
va:257)
at
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:151)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:567)
at
org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContext
Valve.java:245)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.ja
va:199)
at
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:151)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:567)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:184
)
at
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:151)
at
org.apache.catalina.cluster.tcp.ReplicationValve.invoke(ReplicationValve.jav
a:182)
at
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:149)
at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:164
)
at
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:149)
at
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:578)
at
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:149)
at
org.apache.catalina.authenticator.SingleSignOn.invoke(SingleSignOn.java:490)
at
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:149)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:567)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java
:156)
at
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:151)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:567)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:972)
at
org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:206)
at
org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:339)
at
org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:415)
at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:716)
at
org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:650)
at
org.apache.jk.common.SocketConnection.runIt(ChannelSocket.java:829)
at
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.jav
a:688)
at java.lang.Thread.run(Thread.java:534)
Looking deeper into my log, I found this occurs on startup from both
instances:
INFO: Starting clustering manager...:/ourapp
Apr 13, 2004 2:10:26 PM org.apache.catalina.cluster.session.DeltaManager
start
WARNING: Manager[/ourapp], requesting session state from
org.apache.catalina.cluster.mcast.McastMember[tcp://127.0.0.1:4001,127.0.0.1
,4001, alive=1259]. This operation will timeout if no session state has been
received within 60 seconds
Apr 13, 2004 2:11:26 PM org.apache.catalina.cluster.session.DeltaManager
start
SEVERE: Manager[/ourapp], No session state received, timing out.
But latter in the log is:
Apr 13, 2004 2:12:04 PM org.apache.catalina.cluster.session.DeltaManager
start
WARNING: Manager[/servlets-examples], requesting session state from
org.apache.catalina.cluster.mcast.McastMember[tcp://127.0.0.1:4001,127.0.0.1
,4001, alive=1259]. This operation will timeout if no session state has been
received within 60 seconds
Apr 13, 2004 2:12:04 PM org.apache.catalina.cluster.session.DeltaManager
start
INFO: Manager[/servlets-examples], session state received in 102 ms.
Why would /servlets-examples be able to transfer the state correctly but not
our app? I would assume this would relate to the above
ClassNotFoundException.
Does anyone have any ideas on what is the cause of this problem?
Thank you in advance,
Eric
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
