[ogsa-wg] [glue-wg] OGSA Information Services

Laurence Field Laurence.Field at cern.ch
Fri Aug 17 08:45:50 CDT 2007


Hi Omer,

Each grid is currently using a different discovery mechanism. This aim 
of the SAGA work is to provide an API which hides these differences and 
enables the user to discover resources in all grids. I believe this is 
the functionality which Gerson was talking about.

Standardizing the discovery methods is something that we should look 
into and the mechanisms used in many P2P systems should definitely be 
investigated.


Laurence


The SAGA effort is trying to


Omer F. Rana wrote:
> Hi Laurence,
>
> Have you looked at the discovery mechanisms found in peer-2-peer 
> systems -- which are much
> more likely to scale? There has been work in integrating P2P concepts 
> with directory services
> also.
>
> My understanding of SAGA effort is that they identify that a discovery 
> service is necessary -- but not
> how the actual discovery mechanism works (as this is outside, surely, 
> the scope of SAGA)?
>
> regards
> Omer
>
>
> Laurence Field wrote:
>> Hi Gerson,
>>
>> A common information system client would bets fit will with the SAGA 
>> work. They are already working on an API for Service discovery which 
>> will use plugins to find information from the different grids.
>>
>> The OGSA Information Services group is currently looking it existing 
>> technologies used in information systems. Your experiences with MDS4 
>> and XPath would be valuable input to this group.  Do you have 
>> anything available which documents your experiences?
>>
>> Thanks
>>
>> Laurence
>>
>>
>> Gerson Galang wrote:
>>  
>>> Hi all,
>>>
>>> I don't have anything against having another layer sitting on top of 
>>> all different Grid information systems implementation but I'm just 
>>> not sure if that model will scale.
>>>
>>> I got interested in this discussion because I'm developing an 
>>> application which is somewhat related to what I'm going to recommend 
>>> below. The application is being developed for the Australian Grid 
>>> users and developers and is going to be used in querying an MDS4 
>>> index service which uses the GLUE 1.2 schema. We have specified our 
>>> own query language for querying the information system because we 
>>> didn't want developers to write XPath queries if they directly 
>>> interact with MDS4. As you know a very simple resource condition in 
>>> an info systems query can turn out to be a very long query string 
>>> when converted into XPath especially XPath 1.1 which is what MDS4 
>>> only understands.
>>>
>>> This group should probably look into implementing a similar generic 
>>> Grid info systems client application for all the Grid info systems 
>>> implementations around the world. Since the plan is to use the GLUE 
>>> schema, there won't be any issues with specifying a standard query 
>>> language that users can use with this client. The client will need 
>>> to be able to query a "registry of endpoints" service to get 
>>> information about the endpoint, query implementation (eg. wsrf/mds4, 
>>> mds2, etc), and the query language (xpath, xquery, ldap, sql) to use 
>>> for the info systems. The client will be the one in charge of 
>>> transforming the user's query into the respective query languages 
>>> used by the different Grid information systems implementations. I 
>>> think we'll get a quicker response if we query the "registry of 
>>> endpoints" service than the top level information system which 
>>> indexes all the Grid resource information around the world.
>>>
>>> Our application can only handle a very simple query at the moment. 
>>> See link below..
>>>
>>> https://www.grid.apac.edu.au/repository/svn/infosystems/GlueSchemaQueryLib/README 
>>> <https://www.grid.apac.edu.au/repository/svn/infosystems/GlueSchemaQueryLib/README> 
>>>
>>>
>>> but we have plans of extending the language later on to support 
>>> queries like "(Site.Latitude > 0 and Site.Latitude < 50)". Composing 
>>> a query for the GLUE schema shouldn't be that hard. The only thing 
>>> which makes the query complicated is the language we use in querying 
>>> the Grid info systems.
>>>
>>> I'm just not sure if what we are implementing is something you would 
>>> want to look into.
>>>
>>> Regards,
>>> Gerson
>>>
>>> On 8/4/07, *Andreas Savva* <andreas.savva at jp.fujitsu.com 
>>> <mailto:andreas.savva at jp.fujitsu.com>> wrote:
>>>
>>>     The presentation Ravi is referring to is
>>>     https://forge.gridforum.org/sf/go/doc14456?nav=1
>>>     <https://forge.gridforum.org/sf/go/doc14456?nav=1>
>>>
>>>     Subramaniam, Ravi wrote:
>>>     > Hi Hiro/Felix,
>>>     >
>>>     > Currently the examples in the document are from "academia" (not
>>>     that I
>>>     > am against that as most who know me will attest) but in the
>>>     spirit of
>>>     > including enterprise examples would it make sense to include the
>>>     > implementation that I presented at the OGSA F2F in Manchester 
>>> as an
>>>     > example for the enterprise case?
>>>     >
>>>     > Ravi
>>>     >
>>>     > -----Original Message-----
>>>     > From: ogsa-wg-bounces at ogf.org <mailto:ogsa-wg-bounces at ogf.org>
>>>     [mailto:ogsa-wg-bounces at ogf.org <mailto:ogsa-wg-bounces at ogf.org>]
>>>     On Behalf
>>>     > Of Hiro Kishimoto
>>>     > Sent: Wednesday, August 01, 2007 2:49 PM
>>>     > To: ogsa-wg
>>>     > Cc: glue-wg at ogf.org <mailto:glue-wg at ogf.org>
>>>     > Subject: Re: [ogsa-wg] OGSA Information Services
>>>     >
>>>     > Hi all,
>>>     >
>>>     > Per Felix's request, I've upload revised draft onto the 
>>> GridForge.
>>>     >
>>>     > https://forge.gridforum.org/sf/go/doc14692
>>>     >
>>>     > We will discuss it at Thursday's call.
>>>     >
>>>     > Thanks,
>>>     > ----
>>>     > Hiro Kishimoto
>>>     >
>>>     > -------- Original Message  --------
>>>     > Subject: Re:[ogsa-wg] OGSA Information Services
>>>     > From: Hiro Kishimoto < hiro.kishimoto at jp.fujitsu.com
>>>     <mailto:hiro.kishimoto at jp.fujitsu.com> >
>>>     > To: ogsa-wg <ogsa-wg at ogf.org <mailto:ogsa-wg at ogf.org>>
>>>     > Cc: felix.ehm at cern.ch <mailto:felix.ehm at cern.ch>
>>>     > Date: 2007/07/26 12:55
>>>     >
>>>     >> Hi all,
>>>     >>
>>>     >> Discussion material for Information Services by Laurence 
>>> Field and
>>>     >> Felix Ehm is now on the GridForge.
>>>     >>
>>>     >> https://forge.gridforum.org/sf/go/doc14692
>>>     <https://forge.gridforum.org/sf/go/doc14692>
>>>     >>
>>>     >>  > This document covers the problem description, experience in
>>>     GIN,  >
>>>     >
>>>     >> overview of existing systems, generalized system and 
>>> suggested  >
>>>     >> areas for standardization.
>>>     >>
>>>     >> Please have a look before the call today.
>>>     >>
>>>     >> Felix Ehm will lead the discussion.
>>>     >>
>>>     >> Thanks,
>>>     >> ----
>>>     >> Hiro Kishimoto
>>>     >>
>>>     >>
>>>     >> --
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>>>     >>
>>>     >>
>>>     >
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>>
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