[ogsa-bes-wg] Re: [jsdl-wg] Questions and potential changes to JSDL, as seen from HPC Profile point-of-view

[Marvin Theimer]

Hi;

While it is certainly interesting to explore multiple languages with
different levels of expressiveness, the HPC profile work faces a
challenge that I would argue is mostly focused on your first point
around simplicity.  This is because interoperability gets harder the
more complicated the design and the working group also faces a time
deadline of end-of-summer.  So, whereas I very much encourage you and
others to explore richer languages, the one I'm interested in (for the
moment) is the first one.

>From that perspective, I want a simple, practicable means of specifying
both job submission requirements as well as available resource
descriptions (where we all agree that "available" means "available to
the requestor", not "raw availability").  I see two "base" cases for
describing available resources:
- Some simple ways of describing aggregates, such as the number of
available compute nodes in a cluster or the overall "load" of a system
(a number between 0" and 100%).
- A simple way of describing the actual hardware/software resources
available in a system so that clients like simple meta-schedulers can at
least get at the raw data (with all the caveats about how much of the
raw data to expose to any given requestor).  This second type of
description seems like it could be achieved with Donal Fellows'
suggestion of an array of jsdl infosets.

I fully recognize that these two base cases only cover some of the
common scenarios that can occur in grids, but I would argue that they
cover an important set and they are relatively easy to provide, implying
that the HPC profile work could employ them without too much delay.


Marvin.

-----Original Message-----
From: Michel Drescher [mailto:Michel.Drescher at uk.fujitsu.com] 
Sent: Friday, June 09, 2006 3:35 AM
To: Karl Czajkowski
Cc: Donal K. Fellows; Marvin Theimer; JSDL Working Group;
ogsa-bes-wg at ggf.org; Ed Lassettre; Ming Xu (WINDOWS)
Subject: Re: [ogsa-bes-wg] Re: [jsdl-wg] Questions and potential changes
to JSDL, as seen from HPC Profile point-of-view

Karl Czajkowski wrote:
> One thing Donal mentioned which I would like to emphasize:
> 
> The discovery ought to be "what types of job are acceptable" and not
> what resources are there.  Or rather, the latter is part of some
> administrative interface which is misleading for job-submitting users
> and middleware.

Yes! Yes! *waves the supporting flag*

> This may sound pedantic, but it will be crucial for interop. The
> discovery has to capture realistic operating policy, and not just give
> enticing catalogues of resources which can never be combined in a
> single request!

Hit base.

After reading this mail, we are probably best fitted if we provide *two*

resource models. Which may sound impractical, wasted resources or even 
impossible, I think the idea may be worth exploring:

(Note that I take quite some assumptions for granted for the sake of 
simplicity:)

While system administrators are interested in making the best use out of

their machines (simple reason: return of investment), job submitters are

interested in having their jobs actually executed rather than optimised 
'til the last percent (while I acknowledge that there actually are 
submitters that do want to or even need to optimise that way, I think 
that this is a relatively small subset of Grid users at least in the 
future).

A solution to this dilemma may be to provide two "languages", one 
fitting each group best: One language that job submitters use to specify

resources they need, which sacrifices accuracy for practicability. This 
can be very simple, even name/value pairs.

The other language, however, aims for maximum accuracy that I envision 
to be a feature rich, (strongly?) typed representation of their
resources.

Obviously, these two languages need matching when a job is submitted. 
The natural candidate for that is (Donal, forgive me for inaccuracy 
here) "something" coming from the RSS WG.

Any boos, rotten eggs?

Cheers,
Michel

-- 
Michel <dot> Drescher <at> uk <dot> fujitsu <dot> com
Fujitsu Laboratories of Europe
+44 20 8606 4834