[jsdl-wg] JSDL vs NorduGrid xRSL: a comparison (fwd)

[Andrew Stephen McGough]

Dear Oxana,

Here is a quick reply to your request. Rather than address the 
individual issues you have raised I'll give a brief description of why 
the scope of the JSDL group is as it is.

The JSDL group started with a broad vision of providing a full XML 
language for job submission into the Grid (as an aside I came to the 
group with JDML and XML version of JDL from EDG). This however proved to 
be far too much to get agreement on. You talk of "this isn't workflow 
its just ...", many people came to the group saying similar things. This 
became a big problem for JSDL as people came along with such items each 
of which didn't make a workflow language but the sum of them did. This 
put the group into stagnation as arguments about workflow overwhelmed 
the group. Since this we have taken anything that could lead to this and 
put it out of scope. That is not to state that it will always be out of 
scope - but rather we class it as out of scope until JSDL 1.0 is 
complete. Once we have achieved this goal we shall re-visit many of 
these areas and see how they can be adopted into JSDL - or potentially 
propose the formation of new groups to define how to achieve these 
"features".

We are aware of many users and system developers that require many of 
the features that you discuss. However, in order to get any form of spec 
out we have tightened the spec down to the submission of a single job 
with a hard set of requirements.

To take a specific example of the parameter sweep application case you 
describe - I am aware of groups using JSDL who desire these features and 
they are looking into extensions to JSDL which will allow this without 
the need to generate thousands of JSDL documents. Though as stated 
already this is well outside the scope of JSDL 1.0.

To help you to understand what we have defined to be in and out of scope 
I'll refer you to the JSDL document section 3 (the current version can 
be located at 
https://forge.gridforum.org/projects/jsdl-wg/document/draft-ggf-jsdl-spec/en/18). 
As to where to submit items which are out of scope. We are currently 
working on outputting v. 1.0 of JSDL and you can propose items that we 
should look into post 1.0. However,  if you feel that the item is well 
outside of our defined scope you may decide it is best to form your own 
group in GGF to work in that area. Many people in the JSDL group may 
wish to join in on such effort if appropriate to their core desires.

Hope this is of some help,

steve..

Oxana Smirnova wrote:

> Hello Donal,
>
> many thanks for replying, hope you (or other group members) also had 
> time to look through the document. I am new to JSDL business, but have 
> quite some experience with "real" job description languages used for 
> great variety of applications in EDG/LCG/gLite (JDL) and NorduGrid/ARC 
> (xRSL), thus I have some questions that perhaps are just FAQ of this 
> group, see below.
>
>>  a) This should be possible through either the existing subelements of
>>     the POSIXApplication element, or through extension. However I'd love
>>     to see more input from you on this as part of the development of the
>>     next version of the spec.
>
>
> There are several elements that can be easily added; 
> runtimeenvironment is just one of them. What is this group's criteria 
> for an element to be added to the specs? What kind of arguments should 
> I present to support each case? Would it be sufficient to tell that 
> few hundred users find it convenient, and so do Grid m/w developers 
> and site owners?
>
>>  b) This should be done by wrapping the JSDL singletons inside some
>>     larger XML dialect that describes the relationship of the basic jobs
>>     to each other. Although we want to support workflows, we've always
>>     pushed the workflow bit of it out of scope so we can get agreement
>>     on the rest of everything. :^)
>
>
> I don't think that describing several jobs in one script has anything 
> to do with workflow. It's up to the workload management system to 
> interpret it, but for the user's convenience it would be nice to 
> include into JSDL a possibility to specify several jobs. No need for a 
> "larger XML dialect", just one more super-element. Here's a use case: 
> I want to submit 10000 jobs that differ only in one input parameter. I 
> have a tool that generates JSDL; and I'd hate to fill my disk with 
> 10000 small files. You are not going to create a dedicated workgroup 
> to produce a two-line spec that describes JSDL concatenation, are you?
>
>>  c) I think we're punting this one out to WS-Agreement (over a space of
>>     JSDL terms). It gets really complicated otherwise as you start to
>>     try to describe spaces of coupled terms...
>
>
> Eh, nobody promised it's going to be easy :-) I understand that XML is 
> just a markup language, not quite suited for task definition, because 
> task description normally includes conditions "if then else", 
> relations "and", "or", and negations "not". For example, "buy X amount 
> of apples if they are red, else buy Y amount of pears and Z amount of 
> bananas". This is a  single task, these are not separate jobs. It does 
> not describe workflow, because it does not specify in which shop these 
> apples or pears should be purchased (doesn't even say it should be the 
> same one), or when, and not even the price. JSDL presently can't 
> describe such a job. I don't even see how two separate job 
> descriptions can be merged by another *XML* dialect into one - XML is 
> not really made for it. In real life, I've had plenty of jobs like "if 
> a site has outbound connectivity, stage in this, else stage in 
> something different". Globus' RSL allows this, and I'm sure it's a 
> part of job description, not workflow.
> It is an instruction for the execution site, not for the workload 
> manager/broker.
>
>> In summary, "why isn't it possible now", "out of scope", and "out of
>> scope". But that's just a bit short and I think you'll prefer the longer
>> outline above. ;^)
>
>
> I'd like to learn what is the scope, I guess - and where to submit 
> things that are out of it :-)
>
> Oxana
>
>


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Dr A. Stephen McGough                       http://www.doc.ic.ac.uk/~asm
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