[Mulgara-general] Can't connect to remote Mulgara repository using ConnectionFactory

Life is hard, and then you die ronald at innovation.ch
Fri Nov 21 02:55:30 UTC 2008


On Thu, Nov 20, 2008 at 12:26:28PM -0500, Alex Hall wrote:
> Paul Gearon wrote:
> [snip]
> > So RMI can't connect to it at all, huh? What about HTTP? On the
> > WIndows box, try to retrieve:
> > http://SearchMaster:8080/sparql/?query=select+%24subject+%24predicate+%24object+from+%3Crmi%3A%2F%2FSearchMaster%2Fserver1%23sampledata%3E+where+%7B%24subject+%24predicate+%24object%7D
> > 
> > While typing this, it occurred to me to ask about your DNS. Is
> > SearchMaster resolving to 192.168.1.10 for you? Try changing your
> > graph name to:
> > rmi://192.168.1.10/server1#sampledata
> > 
> > You can also try the URL with addresses instead of host names:
> > http://192.168.1.10:8080/sparql/?query=select+%24subject+%24predicate+%24object+from+%3Crmi%3A%2F%2F192.168.1.10%2Fserver1%23sampledata%3E+where+%7B%24subject+%24predicate+%24object%7D
> 
> This reminds me of another issue I've experienced in the past.  RMI connections
> with a Mulgara server tend not to work unless the hostname on the server is
> properly set (can be easily verified using the Linux 'hostname' command).  The
> hostname needs to be a real hostname (not "localhost") which resolves to the
> external interface (not the loopback address).  Otherwise RMI connections from
> remote machines won't work; I'm not sure if this is a problem with the
> canonicalization of server names that Mulgara does, or is deeper in Java RMI.

Ah, good point, this may be the problem.

David, what does 'optimus' resolve to on the _server_ itself? E.g. if
you 'ping optimus' on the server what ip-address does it indicate it's
pinging? If it's not the 'public' ip-address, but say 127.0.0.1 then
that is your problem.


  Cheers,

  Ronald




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