Description

This article provides troubleshooting tips for multicast issues, when a second Junos Space server is added to the fabric. 

Symptoms

  • With Junos Space 11.2 or later, multicast needs to be enabled in the network between the Junos Space servers to form a fabric.
  • When adding the second Junos Space server to the fabric, you may encounter an error message indicating that multicast is not enabled. You can verify the status of multicast in your network, between the two Junos Space servers, by using the Jboss multicast tool.
  • You can also look at the /tmp/mcast.log files on both Junos Space servers to see if there is any indication of traffic from the other Junos Space node. If the /tmp/mcast.log file contains information on its own server but not on the other server, multicast is not enabled between the two servers.
  • If IGMP snooping is enabled on a switch between the two Space servers, a fabric will not form because the Jboss version used by Junos Space does not work properly with IGMP snooping enabled. In this case, disable IGMP snooping, and then add the secondary node, provide an IGMP querier for the VLAN on which the Space nodes reside, or configure a static group (see below).
  • If you have verified that multicast is enabled between the Junos Space servers, but the second server is not added to the fabric, try disabling the firewall from both Junos Space servers and add it again. 
  • Junos Space uses the default gateway as the pingable IP address, so the address must be reachable, or else the fabric will not form correctly.

Solution

To run the Junos Space Jboss multicast tool, open two SSH sessions to each Junos Space server, and run McastReceiver and McastSender on both servers. The mcast_addr will be different from the example below. You can obtain the mcast_addr by looking under file /etc/hosts  for the jmp-MCAST entry on the primary node.

Through Space 13.1

  • To run McastReceiver:
cd /usr/local/jboss/server/all/lib;
java -cp jgroups.jar org.jgroups.tests.McastReceiverTest -mcast_addr 228.0.199.110 -port 45566
//45566 is the default port for jgroups udp mcast.
//228.0.199.110 is the mcast address this space cluster uses.
  • To run McastSender:
cd /usr/local/jboss/server/all/lib;
java -cp jgroups.jar org.jgroups.tests.McastSenderTest -mcast_addr 228.0.199.110 -port 45566


Space 13.2 to Space 14.1R3

  • To run McastReceiver:
cd /usr/local/jboss/modules/system/layers/base/org/jgroups/main/;
java -cp jgroups-3.2.7.Final.jar org.jgroups.tests.McastReceiverTest -mcast_addr 228.0.199.110 -port 45566
//45566 is the default port for jgroups udp mcast.
//228.0.199.110 is the mcast address this space cluster uses.
  • To run McastSender:
cd /usr/local/jboss/modules/system/layers/base/org/jgroups/main/;
java -cp jgroups-3.2.7.Final.jar org.jgroups.tests.McastSenderTest -mcast_addr 228.0.199.110 -port 45566


Space 15.1 onward

  • To run McastReceiver:
cd /usr/local/jboss/modules/system/layers/base/org/jgroups/main/;
java -cp jgroups-3.2.13.Final-redhat-1.jar org.jgroups.tests.McastReceiverTest -mcast_addr 228.0.199.110 -port 5555
//5555 is the default port for jgroups udp mcast.
//228.x.x.x is the mcast address where x.x.x is the last three bytes of the first node's IP.
//228.0.199.110 is the mcast address this space cluster uses.
  • To run McastSender:
cd /usr/local/jboss/modules/system/layers/base/org/jgroups/main/;
java -cp jgroups-3.2.13.Final-redhat-1.jar org.jgroups.tests.McastSenderTest -mcast_addr 228.0.199.110


Test setup

111 is the first node; 112 is the 2nd node.

  • 1st window: 111, with receiver running
  • 2nd window: 111, with sender running
  • 3rd window: 112, with receiver running
  • 4th window: 112 with sender running


Observation

  • In the 1st window, UDP traffic is displayed with keywords such as NAKACK and so on.
  • In the 2nd window, type hello world from 111 . The 1st and 3rd windows should receive this message.
  • In the 4th window, type hello world from 112 . The 1st and 3rd window should receive this message.


Example: Configure IGMP-Snooping Static Group

[edit protocols]
root@switch# show
igmp-snooping {
    vlan vlan1 {
        interface ge-0/0/0.0 {     ### Include switch interface for first Space Node.
            static {
                group 228.0.199.110;
            }
        }
        interface ge-0/0/1.0 {     ### Include switch interface for next Space Node.
            static {
                group 228.0.199.110;
            }
        }
    }
}

Modification History

2017-06-01: For the section on Space 15.1 onward, corrected mcast receiver address.