[Beowulf] motherboards for diskless nodes

Reuti reuti at staff.uni-marburg.de
Sat Feb 26 04:27:50 PST 2005

Quoting John Hearns <john.hearns at streamline-computing.com>:

> On Fri, 2005-02-25 at 10:31 -0800, Greg Lindahl wrote:
> > 
> > Doesn't make any sense; I have seen people describe such systems where
> > they download a disk image when a batch job wants a different software
> > load. It's certainly doable that way: it does have different tradeoffs
> > from the diskless case, but if it gives you a headache, it's probably
> I've always dreamed of using User Mode Linux images for this.
> In a Grid-based world, prepare a UML instance which has all the
> libraries and runtime to run your code. Ship it across the grid with
> your executable. 
> The cluster at the receiving end can be running any distribution - it
> runs your UML in a sandbox.

I would like to have it also: if any queuing system wants to kill a job on a 
node: just shutdown the virtual machine. And you also get off of any semaphores 
and shared memory segments (and message queues), which maybe left behind in 
other cases. I saw leftover semaphores not only on Linux, but also on AIX and 
SuperUX in case of a job abort. Is there any safe way to release them after a 
job? I already got the idea, to catch them with a library which wraps the 
shmget(),.. calls by using LD_PRELOAD to get the IDs, and then release them in 
an epilog after the jobs (seems working, but of course only for dynamically 
linked applications).

Just got the hint to look at Meiosys. Seems they have such features in their 
virtual machines.

Cheers - Reuti

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