Re: Session replication in Geronimo clustering

Filip Hanik - Dev Lists Wed, 29 Mar 2006 08:26:34 -0800

it would be one of these, they should all be set to a value.


tcpListenAddress="auto"
tcpListenPort="9015"
tcpSelectorTimeout="100"
tcpThreadCount="6"

also, if tcpListenAddress says "auto" instead of an IP address, the thefollowing code gets executed


public java.net.InetAddress getBind() {
       if (bind == null) {
           try {
               if ("auto".equals(tcpListenAddress))

tcpListenAddress =java.net.InetAddress.getLocalHost().getHostAddress();

               bind = java.net.InetAddress.getByName(tcpListenAddress);
           } catch (IOException ioe) {

log.error("Failed bind replication listener onaddress:"+ tcpListenAddress, ioe);

           }
       }
     return bind;
}

so, if there is an error getting the correct address for the localhostmachine, it will return null, and could cause your nullpointer exception


my guess is of course that the attribute is missing all together.

Filip




Jeff Genender wrote:

Filip,

Thanks for the input...any idea on the missing attribute?

Jeff

Filip Hanik - Dev Lists wrote:

gentlemen,
looks like there is an attribute missing from the
"<Cluster...>*<Receiver.../>*</Cluster>" element.
the ReplicationListener.listen() method just gets the listen address (or
tries to resolve the name, then gets the port)
then it starts up a server socket using NIO.

the other error, no active members in group, just means that the tomcat
instances didn't discover each other using multicast heart beats.

Lets get the ReplicationListener error first, then we can move on to
membership, can you post your tomcat config file
PS. the error is not related to mod_jk, its in the tomcat java code.
thanks
Filip

Phani Madgula wrote:

Hi,

I have been trying to use tomcat clustering with Geronimo for a

customer application. Sometimes, I face the following problem.

I downloaded apache2.0.54 and mod_jk_1.2.15 and tested clustering. I
have three machines on a same subnet one windows and other are linux
boxes. I have also enabled IPMulticast and no firewalls between systems.

To my observation, session replication is not working. However,
loadbalancer is able to fail-over successfully.

When I shutdown the instance which is serving the HttpRequests, it
will throw an exception stating "not able to start cluster listener"
and also "no active members in the cluster"

11:09:10,572 DEBUG [WebappLoader] Stopping this Loader

11:09:10,573 ERROR [ReplicationListener] Unable to start cluster
listener.

java.lang.NullPointerException

at
org.apache.catalina.cluster.tcp.ReplicationListener.listen(ReplicationListener.java(Compiled
Code))

at
org.apache.catalina.cluster.tcp.ReplicationListener.run(ReplicationListener.java:125)


at java.lang.Thread.run(Thread.java:570)

11:09:10,573 DEBUG [StandardContext] resetContext Geronimo
:j2eeType=WebModule,name=//localhost/servlet-examples-cluster,J2EEApplication=none,J2EEServer=none
null

11:09:10,575 DEBUG [StandardContext] Stopping complete

or

11:03:07,998 INFO [DeltaManager] Manager [/servlet-examples-cluster]:
skipping state transfer. No members active in cluster group.

I have tested with both mod_jk_1.2.14 & mod_jk_1.2.15, but failed.

Any ideas on why this error comes?..

Thx

phani

Re: Session replication in Geronimo clustering

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