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Re: [Testbed-admins] Minibosses

I would suggest talking to some of the guys from DETER about this - I
bet Keith would respond to a post on testbed-admins. They have done
something like this, since half their nodes are at ISI and half are at
Berkeley. But, I know embarrassingly little about what they've actually
done. I think that, at the very least, they are caching Frisbee images
on the Berkeley side (their boss is on the ISI side).


Okie.


If we were to do this, we'd start out:
*modifying tmcd to be able to hand out proper URLs
	(FTP might be better than HTTPS for bandwidth concerns)
	for the FreeBSD images to get their OS


Sorry, I think I'm missing something - you're talking about a URL in
place of the multicast address that it hands out right now?


Yes. As I understand, right now wideareanodes get a relative path
to fetch using wget from boss, and standard nodes launch frisbee
and expect to download from boss that way. I'd like to add another
code path for "with miniboss" to the maintenance images that would
pass out a full URL for clients to try to fetch.


*modifying tmcc to be able to understand that and react accordingly


'React accordingly' here would be to fetch the image over ftp, etc. and
run imageunzip, instead of frisbee?


Yes.


*modifying the support scripts so that if connections to a miniboss
	fail, the client will tell the real boss, which will fallback to
	telling the client to use ops instead


This sounds like a very good idea, but I'm confused about the statement
about using ops. Also, I would include a checksum for OS images, so that
the client can tell if the miniboss somehow has a stale image, and fall
back to the real one.


Oops, I meant boss (which, at least in our testbed, serves the images
it sees on ops/fs via NFS and hands them out via frisbee/http). Although..
it might be worth considering, for widearea support, running a ftpd or
small httpd on fs/ops to hand out these images - it seems like an odd choice
to make boss be involved in handing out those huge files if boss has to
access those same images via NFS behind the scenes anyhow (although I guess the
shared images are actually on boss).

--
Pat Gunn
Principal Research Programmer/Analyst, CMCL
School of Computer Science, Carnegie Mellon University