[Beowulf] RE: portable clusters

[Robert G. Brown]

On Wed, 30 Nov 2005, Jim Lux wrote:

> At 12:40 PM 11/30/2005, David Mathog wrote:
>> Since you have to reboot the laptops by hand anyway how much more
>> work would it be to slap a CD in each drive at the same time?
>
> I think you've misunderstood the desired overall configuration.
>
> There's only one laptop in the system, as I envision it.  The cluster is a 
> sealed box, connected by a "wire" (e.g. a network cable) to the one laptop, 
> which runs Windows XP.  There's one "Big red switch" on the cluster box that 
> turns it on and off.   (well.. you might want a few switches.. one for power, 
> and one for reset, although, with diskless nodes, it's not clear that power 
> cycling isn't as good a way as any to reset the nodes)

So run the server addition of Windows XP, presuming that it exists, or
Win2K server if not, on the laptop.  Microsoft does not make it easy, or
even possible, to run a desktop OS as a server as that would keep them
from making the extra $500 or so they get for a server license.

To REALLY appreciate the turn of this screw you have to read about the
20 or so systems they claim one can support per server before
performance degrades, and about the "client access licenses" one has to
buy.

Two final alternatives (browsing the MS Server sites, including their
simply lovely collection of white papers "proving" that Windows servers
are more secure and have lower TCO than linux server:-) is this:

   http://www.microsoft.com/windowsserversystem/virtualserver/evaluation/vsoverview.mspx

This is basically vmware AFAICT on the Windows side -- you can run linux
as a task under Windows.  MAYBE you can give linux control over dhcp and
tftp, in which case you're done on any laptop with about 10 GB free
space for linux itself and a warewulf image.  Performance might suck if
the nodes are constantly whonking on the server for pages, but if they
are memory rich they'll probably load up cache and go for many/most
jobs that fit.

Then there is the other way around -- boot linux.  Run Win XP in vmware.
The linux side can DEFINITELY support the pxe booting of a warewulf
image; vmware can almost certainly support your WinXP session at a
performance level adequate to manage an interactive session.  If you
want to CONTROL the cluster from the WinXX side, well, you'll probably
have to do some coding, but that's only to be expected given that this
whole thing is more than a bit of a hack (it is a whole lot easier and
saner to just run linux on the laptop to boot AND run the cluster and
not run Windows at all).  SOMEWHERE you'll have to provide glue and
migration to WinXX if a design criterion really is to eventually put
stuff into WinXX file formats or onto Windows boxes for processing with
its "advanced" tools.  You can still choose whether or not to make this
translation occur before or after the laptop.  It is trivial to make the
laptop a Windows server (samba) so that the DATA space it provides to
the nodes is also exported to a WinXX network.  vmware will likely
permit that space to be hermaphroditically remounted within the laptop
itself in separate interactive sessions.

Both of these solutions will cost money, of course, but hey, tanstaafl.

    rgb

>
> i.e. there's no CD ROM drive on the cluster nodes.. they boot off the net.
>
>
> James Lux, P.E.
> Spacecraft Radio Frequency Subsystems Group
> Flight Communications Systems Section
> Jet Propulsion Laboratory, Mail Stop 161-213
> 4800 Oak Grove Drive
> Pasadena CA 91109
> tel: (818)354-2075
> fax: (818)393-6875
>
>
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-- 
Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu