[Beowulf] High Performance SSH/SCP
prentice at ias.edu
Fri Feb 15 13:54:41 PST 2008
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Mark Kosmowski wrote:
> Robert G. Brown wrote:
> > Rsh "and" anything else is difficulty squared,
> > and kerberos isn't the universally implemented tool it was a
> decade ago,
> > largely superceded by ssh and/or ssl connections. So finding
> experts to
> > help you make it work if you're a newbie isn't going to be that easy.
> I don't think there's anything difficult about setting up rsh, ssh or
> kerberos for anyone who know how to read a manual. A newbie shouldn't be
> setting up a cluster in the first place. That's advanced kung-fu best
> left to the black belts. Letting a neophyte build and run an HPC cluster
> is some kind of oxymoron.
> Yes, I know that professors usually tell some green graduate student to
> go build a cluster for the dept, but that's a completely different topic
> outside the scope of this list...
> I'm either not as much of a newbie / neophyte as I think I am or I
> missed the memo about this list being for pro's only.
> As far as the scope of this list, as clustering becomes more and more
> prolific, there are going to be more and more newbies. This list is,
> like it or not, one of the "franchise" clustering information portals.
> When I was first building my first (and only) personal cluster I stopped
> by here and at ClusterMonkey primarily to get my feet wet. Most of the
> things were (and, frankly, still are) quite above my head, but I was
> made aware of many other resources and things to think about - this
> increased understanding is helpful even if I don't implement many of the
> ideas dicussed here. The end result is a functioning cluster - mayhps
> not nearly as elegant as many of the clusters many of the others on the
> list maintain, but I get data nonetheless.
> I think it would be a disservice to the community to turn away cluster
> newbies from this list. At the very least encouragement and resource
> links should be provided. Appropriately experienced list members with a
> bit of time are also free to take discussions off to private email if
> that is more appropriate than the list in general. After all, the world
> is replete with examples of complete newbie's coming up with ideas to
> revolutionize the fields to which they are new.
> Mark Kosmowski
Let me rephrase my response to RGB's statement:
I think the difficulties of setting up rsh/ssh/and kerberos are greatly
exaggerated. SSH usually works out of the box, except for the
password-less login that requires generating keys. That part is
relatively simple, and is documented all over the web.
4 years ago, I set up kerberos for the very first time, without any
prior experience. I read through the relevant chapters of the O' Reilly
Kerberos book and had it up and running in only a couple of days. Most
of that time was spent reading. I disagree with RGB's equation
rsh + anything = (difficulty)^2
I found that once kerberos is set up, using kerberized rsh is
essentially invisible, therefore
rsh + kerberos = difficulty
which is a first-order relationship.
If anything, setting up rsh is the most difficult one. Why? Since rsh is
so insecure, the distro producers/vendors have created many hurdle you
must hop to get it working (correct file and owner permissions, etc.)
Linux Software Support Specialist/System Administrator
School of Natural Sciences
Institute for Advanced Study
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