[ogsa-wg] Re:[RSS Architecture Discussion]

[Mathias Dalheimer]

Hi all,

I am happy to see this discussion. Let me state my position in two 
steps: Wearing my researcher hat and my OGSA-RSS-Cochair hat.

As a researcher, I think we need advance reservation in grids for a huge 
class of jobs. I would like to have an agreement between the 
client/consumer and the provider/producer for each job (possibly not for 
very small tasks). The provider should decide which terms he can offer, 
and the client should accept or refuse. A scheduler/resource broker has 
then the duty of bringing clients and provider together. There is no 
such thing as atomicity in distributed systems, therefore I would like 
to have an economic model that punishes participants that violate any 
contracts.

Basically, since the provider needs to execute a given job, he needs to 
know the dependencies of a job and may then map the job to a set of 
local resources, or start provisioning of resources. The broker gathers 
offers from various providers, which consist of multiple properties. The 
client provides information about his preference structure. The broker 
is then responsible for matching the offers to the clients needs. The 
client is then presented with this solution and may confirm it. If one 
of the parties cancels the agreement, the broker should propagate the 
cancelation cost to the entity that caused the cancelation.

As a OGSA-RSS Cochair, I also have to state that this is out of scope. 
RSS deals with the Execution Planing System (EPS) and the Candidate Set 
Generator (CSG). As Donal already wrote, there is no change on the 
environment during the execution of those services. Therefore, the CSG 
can point to a (ordered) set that may suit the needs of a given job, and 
the EPS can then choose an appropriate execution location. There is no 
reservation support at the moment. If the Jobmanager chooses to reserve 
resources, he is on his own. There is no way of supporting e.g. 
coallocation of resources in the RSS.

But nevertheless, I would love to see a short primer document about 
WS-Agreement.

-Mathias