Show Table of Contents
20.7.11. JGroups Troubleshooting
Nodes do not form a cluster
Make sure your machine is set up correctly for IP multicast. There are 2 test programs that can be used to detect this: McastReceiverTest and McastSenderTest. Go to the
$JBOSS_HOME/server/all/lib directory and start McastReceiverTest, for example:
java -cp jgroups.jar org.jgroups.tests.McastReceiverTest -mcast_addr 224.10.10.10 -port 5555
Then in another window start
McastSenderTest:
java -cp jgroups.jar org.jgroups.tests.McastSenderTest -mcast_addr 224.10.10.10 -port 5555
If you want to bind to a specific network interface card (NIC), use
-bind_addr 192.168.0.2, where 192.168.0.2 is the IP address of the NIC to which you want to bind. Use this parameter in both the sender and the receiver.
You should be able to type in the
McastSenderTest window and see the output in the McastReceiverTest window. If not, try to use -ttl 32 in the sender. If this still fails, consult a system administrator to help you setup IP multicast correctly, and ask the admin to make sure that multicast will work on the interface you have chosen or, if the machines have multiple interfaces, ask to be told the correct interface. Once you know multicast is working properly on each machine in your cluster, you can repeat the above test to test the network, putting the sender on one machine and the receiver on another.

Where did the comment section go?
Red Hat's documentation publication system recently went through an upgrade to enable speedier, more mobile-friendly content. We decided to re-evaluate our commenting platform to ensure that it meets your expectations and serves as an optimal feedback mechanism. During this redesign, we invite your input on providing feedback on Red Hat documentation via the discussion platform.