dev@glassfish.java.net

Re: multicast validator: script or asadmin command?

From: Bill Shannon <bill.shannon_at_oracle.com>
Date: Thu, 12 Aug 2010 14:02:55 -0700

Bobby Bissett wrote on 08/12/10 01:31 PM:
> On Aug 11, 2010, at 11:12 PM, Bill Shannon wrote:
>> How about if it were a command that talked to the DAS and asked it to listen,
>> then sent data, and got the results from the DAS? Would that make it easier
>> to use if it required the DAS to be running?
>
> I think that's more overhead than we need, and as it is now it can be run simply with a "java -cp<shoal-gms-impl.jar> <class>" command. The asadmin wrapper around it makes it seem more consistent with other commands, but at heart it's a very low-level diagnostic tool.
>
> It may be that if a node can send multicast traffic then it can definitely receive it, but since I don't know that I like the idea that each node both sends and listens. So if someone runs this to diagnose cluster issues, ideally s/he would telnet/ssh/vnc/etc into each box of interest and run the tool, and starting up the DAS everywhere for that isn't needed.

The point was to make sure the DAS could multicast to/from each instance
machine. Since you're going to need the DAS to create the instances
anyway, why not have it running to do the diagnostic before you create
the instances?

Yes, I suppose it's possible that the DAS could talk to each instance,
but the instances couldn't talk to each other. Diagnosing problems of
that sort is probably beyond what we need to do.