setting up a dual-headed beowulf

[Victor Ortega]

I'm considering setting up a dual-headed beowulf for the sake of
high-availability and some load-balancing of non-parallel tasks.  I
understand I will have to put two ethernet cards in each head and
otherwise set each of them up as though they were the only head in the
beowulf cluster, and that each head should treat the other head as
though it were a node, but can any of you think in advance of any
other potential issues/problems with such a setup?  Have any of you
done such a thing and have any suggestions or warnings you'd be
willing to share?  I won't be using NIS or Kerberos, but I have a
scheme in mind for dealing with password management (from our last
discussion on this topic--thanks to everyone for their suggestions).
I can take care of the high-availability aspects (IP address takeover,
heartbeats, etc.); I just want to make sure I don't break the beowulf
part in the process (particularly the firewall(s) and the internal
network).

I welcome all suggestions.  Once I have this working, I'd be happy to
post a summary statement of what it took to get this working, to help
anyone in the future who might be considering this option.

Victor