Jrockit multicast bug on RHEL4, WLS cluster does not works!

Question

OS and Kernel Version: Linux achilles1 2.6.9-34.0.1.ELsmp #1 SMP Wed May 17 16:59:36 EDT 2006 x86_64 x86_64 x86_64 GNU/Linux
We use Bea Weblogic 8.1SP5 with Jrockit JVM 1.4.2 on RHEL3. We upgraded to operating system to RHEL4, and found that the interface binding for multicast communication does not bind to the correct interface, it is always using the default interface. We tried it from a sample program, and found that the error is in the JVM.
This is a critical error for us, because our application server cluster use multicast for cluster communication.
No error msg. It seems like this BUG:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4082533 but it is solved.
List steps to reproduce the problem:
socket = new MulticastSocket(i);
if(s2 != null)
try
InetAddress inetaddress = InetAddress.getByName(s2);
System.out.println("Using interface at " + inetaddress.getHostAddress());
socket.setInterface(inetaddress);
System.out.println(socket.getInterface());
catch(SocketException socketexception)
throw socketexception;
}

Answer 1

Helo,
You can reproduce it by this way (we have 6 RHEL4 servers, problem is the same). We tried with programs written in C (mcast,Tibco), multicast perfectly works on all interfaces on all servers. But in Java:
Server:
[wlxapp@webex3]$ uname -a
Linux webex3 2.6.9-34.0.1.ELsmp #1 SMP Wed May 17 17:05:24 EDT 2006 i686 i686 i386 GNU/Linux
Problem - with Bea mukticast tester (or any Java class), using the nondefault webex3-priv interface(eth1):
[wlxapp@webex3]$ java -cp wl9.jar utils.MulticastTest -N webex3_priv -I webex3_priv -A 224.1.1.11 Starting test. Hit any key to abort Using interface at 192.168.1.1 Using multicast address 224.1.1.11:7001 Will send messages under the name webex3_priv every 2 seconds Will print warning every 600 seconds if no messages are received
I (webex3_priv) sent message num 1
I (webex3_priv) sent message num 2
I (webex3_priv) sent message num 3
Did not receive any message.
But if we use the default webex3 interface (eth0)
[wlxapp@webex3]$ java -cp wl9.jar utils.MulticastTest -N webex3 -I webex3 -A 224.1.1.11 Starting test. Hit any key to abort Using interface at 10.4.20.4 Using multicast address 224.1.1.11:7001 Will send messages under the name webex3 every 2 seconds Will print warning every 600 seconds if no messages are received
I (webex3) sent message num 1
I (webex3) sent message num 2 Received message 2 from webex3
I (webex3) sent message num 3 Received message 3 from webex3
Works perfectly.
TCPDUMP:Messages are out from server(other srv also see it), so we have problems probably with receiving them:
[root@webex3]# tcpdump -i eth1
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth1, link-type EN10MB (Ethernet), capture size 96 bytes
11:42:56.647362 IP webex3_priv.idmz.t-mobile.intra.afs3-callback > 224.1.1.111.afs3-callback: rx type 95 (1472)
11:42:56.648168 IP webex3_priv.idmz.t-mobile.intra > 224.1.1.111: udp
11:42:56.648245 IP webex3_priv.idmz.t-mobile.intra > 224.1.1.111: udp
We examined the lsof output, the tester bind to all interfaces, so it should receive the messages:
[wlxapp@webex3]$ /usr/sbin/lsof -p 11127
gij 11127 wlxapp 8u IPv4 150320 UDP *:afs3-callback
We tried the test with Java 1.4.2 and 1.5 (Jrockit and Sun), the results are the same.
You can easily reproduce the problem with an RHEL4 server with 2 network interface.
Our real problem that if multicast have problems, our Weblogic clusters does not works.