[ogsa-wg] clarification on the OGSA Job Management capability

[Sergio Andreozzi]

Hi Hiro,

Hiro Kishimoto wrote:
> Hi Sergio,
> 
> We think Job Manager provides more features than BES including:
> - Resource allocation (a.k.a. brokering)
> - Workload management
> - Reservation (including advance reservation)
> - On demand application provisioning
> - On demand data provisioning (more than file staging/de-staging)
> - On demand container provisioning

thanks for pointing me at the document.

Reading the document, I understand that Job Management is a different 
capability than Job Execution.

Is it correct to say that BES identifies a subset of the capabilities 
part of the macro category Job Management? Or are they different?

In my current classification, this is what I've defined so far for the 
Execution Management capabilities set:

ExecMan

ExecMan.JobMan
This capability is related to the capacity of managing the execution of 
a job or set of jobs from start to finish.

ExecMan.JobDescription
This capability is related to the capacity of letting users be able to 
describe a job submission request based on a machine-processable language.

ExecMan.ExecutionAndPlanning
This capability is related to the capacity of building schedules for 
jobs, i.e., the capability of defining mappings between services and 
resources, possibly with time constraints.

ExecMan.CandidateSetGenerator
This capability is related to the capacity of determining the set of 
resources on which a nit of work can execute.

ExecMan.Reservation
This capability is related to the capacity of managing reservation of 
resources for future usage.


In an earlier version I had also ExecMan.BasicExecution, but after I 
thought that it should go under the umbrella of Job Management.

Another possible view is to see Job Management as a second-level macro 
category and then specify a third level of classification, e.g.

ExecMan
ExecMan.JobMan
ExecMan.JobMan.BasicExecution
ExecMan.JobMan.DataProvisioning
ExecMan.JobMan.ExecutionAndPlanning
...

can you comment on the different approaches? Keep in mind that the final 
goal is to use this decomposition to describe a certain Grid middleware. 
For instance, the gLite WMS provides ExecMan.CandidateSetGenerator, 
ExecMan.JobMan, ExecMan.ExecutionAndPlanning, etc.



Thanks, Sergio


> 
> Our EMS scenario document (working draft) gives you more concrete
> ideas.
> 
> https://forge.gridforum.org/sf/go/doc12749
> 
> Hope it helps,
> ----
> Hiro Kishimoto
> 
> Sergio Andreozzi wrote:
>> Dear OGSA-WG,
>>
>> as part of the OMII-Europe project, I'm performing a decomposition of 
>> the functionalities provided by a number of Grid middlewares related 
>> to our project following the capabilities identified in the OGSA 1.5 
>> document.
>>
>> A problem I'm dealing with is about the Job Management service. For 
>> instance, in the gLite middleware, there are two main categories of 
>> services providing job management capability:
>>
>> 1. the Computing Element, that is an abstraction of a batch system 
>> exposing an interface to let other services to submit and manage a 
>> job; in the near future this component will adopt the OGSA-BES 
>> interface, but at the moment it is present in different flavours (GT 2 
>> GRAM, g-Lite CE and CREAM)
>>
>> 2. the Workload Management System (WMS), that is a meta-scheduler and 
>> exposes an interface to let other services to submit and manages a job 
>> (or collection of jobs or DAGs); the WMS not only does Job Management, 
>> but also Execution and Planning, and Candidate Set Generator.
>>
>> My doubt is the following: from the viewpoint of Job Management, are a 
>> meta-scheduler and a computing service semantically different or 
>> identical?
>>
>> If they are identical, is it expected that in a medium future, the BES 
>> interface could be extendend to support the number of job types 
>> handled by a meta-scheduler, hence the meta-scheduler will expose the 
>> same interface of a computing service?
>>
>> If they are not identical, what are the differences?
>>
>> Thanks in advance for your comments,
>>
>>
>> Sergio Andreozzi
>>
>>
>>
> 


-- 
Sergio Andreozzi
INFN-CNAF,                    Tel: +39 051 609 2860
Viale Berti Pichat, 6/2       Fax: +39 051 609 2746
40126 Bologna (Italy)         Web: http://www.cnaf.infn.it/~andreozzi