[Beowulf] Virtualization in head node ?

[Tim Cutts]

On 18 Sep 2009, at 1:15 pm, Robert G. Brown wrote:

> On Thu, 17 Sep 2009, Gerry Creager wrote:
>
>>> I was a dyed-in-the-wool vmware user until quite recently, too,  
>>> but the pain of keeping it running on "current" distros (read:  
>>> Fedora) finally forced me to look elsewhere.  I think you'll be  
>>> pleasantly surprised by VirtualBox if you give it a shot.
>>> Then again, who knows what Oracle will do with it...
>>
>> I'm not sure I'd TRY to keep it running on Fedora.  Too bleeding  
>> edge for my clusters!
>
> I don't use Fedora on clusters, I use it on laptops, where bleeding  
> edge
> is often necessary.  I just got and reinstalled a Studio 17 Dell  
> (which
> came with VoEvil, of course) and it wouldn't even boot the F10 install
> image (at least not without a lot more energy than I had to put into
> it).  F11 it booted, and installed, flawlessly.  From what Google  
> turned
> up, Ubuntu will work too.

Ah, OK, so I can understand the VMware pain from that side.  But the  
pain we were talking about was maintaining old OS services for a long  
time, and of course that's hopefully less difficult; as long as VMware  
don't change the virtual hardware too much, we should be fine (and so  
far they've been very good at maintaining backward compatibility).

I still take the point (that someone made, sorry I don't remember who)  
that there may still be licensing issues for services built on  
proprietary operating systems and such, but in my view that's a good  
argument for building such services on open source software in the  
first place.  "Doctor, it hurts when I poke this sharp stick in my  
eye"... :-)

> The VMware hassle on F11 (and Ubuntu -- actually on current-gen  
> kernels
> in general) has been the exception rather than the rule and seems to  
> be
> due to a surprising lag between recent major changes in some of the
> kernel sources, plus the shift in Fedora from OSS to ALSA-only with  
> OSS
> emulation a deprecated, difficult to restore option.  But I will try
> VBox at my next reasonable opportunity.

> On servers I run Centos or RHEL (licenses and all) as the vendor of  
> the
> software requires.  Generally Centos on top, then VMware, then RHEL  
> VMs.
> Works fine.  The only bad thing I've seen about Centos in the past is
> the dark side of a long term freeze -- some very useful tools and
> libraries have been in rapid development (notably the GSL and Yum).
> RHEL 4 just sucked in this regard, with up2date instead of yum, and an
> early, broken version of the GSL.  Fedora is too fast, RHEL too slow.
> What can you do?


I'm not sure there's any perfect answer to that one.  The Debian  
family of distros have a similar problem.  Debian stable changes too  
slowly, testing is too fast.  Ubuntu seem to have a reasonable  
compromise; two updates a year if you want bleeding edge, and LTS  
releases every so often for those for whom stability is everything.   
The only problem with the debian family, of course, is struggles with  
ISV support, although that is coming, slowly.  VMware now fully  
support Debian as well as Ubuntu as ESX guests, which has made my life  
much easier.  They don't seem to support CentOS, but I just lie to  
VMware and tell it the machine is running Red Hat, and it seems to  
behave fine.

Our solution at Sanger to the stable vs uptodate argument has  
basically been to go with Debian stable, and maintain our own  
repository of backported packages for when we need something more  
recent.  Fortunately the number of packages we've had to backport or  
patch has been fairly small.

Regards,

Tim


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