On 2012-08-20 12:51, stephen.burke@stfc.ac.uk wrote:
glue-wg-bounces@ogf.org [mailto:glue-wg-bounces@ogf.org] On
Behalf Of Florido Paganelli said: Suppose the same machine hosts two RELATED services, that is, one needs the other one for proper functionality. For example a delegation service is needed to submit a job to a job execution service.
This sounds to me like *one* Service with two different types of Endpoint. For example a VOMS server can have voms endpoints to return credentials and voms-admin endpoints to manage VO membership, but they both talk to the same database so there is only one Service. This is the biggest structural change from GLUE 1 to 2 - in GLUE 1 there are only GlueService objects representing endpoints, but in GLUE 2 we introduced the Service concept exactly so they could be grouped together if they provide a shared functionality.
Stephen
Your observations are right, however the model of service you have in mind is monolithic and not distributed; I am in fact speaking about something that was not considered during the GLUE2 "making of". I am speaking about a service wrt the following use case: 1) the service, by design, *has* distributed endpoints, that might run on different hosts. 2) a client would like to gather the endpoints belonging to that distributed service. You can imagine an information system, like a resource-bdii, that runs independenlty from the resource, maybe on a different host. How to relate the resource-bdii endpoint with the resources it serves? I imagine a client collecting information from some index in which you only have GLUE2 endpoints and service records. How to relate these records and infer, for example, that they're on the same machine and/or serve the same resource? Parsing the EndpointURL would be a choice, but you don't need GLUE2 for that... All in all we could call these "service-service" relationships. -- Florido Paganelli Lund University - Particle Physics ARC Middleware EMI Project