[ogsa-wg] use case template

[Chris Kantarjiev]

I was asked by several people to provide an example use case that fits my 
template. Here's a simple one, not related to workflow:

-Title: Resource Barter Services

-Description
Allow metrics to define and decide how and when can resource consumers trade or 
exchange resources already paid for or reserved for themselves. Create an 
exchange mechanism inside a data center between multiple consumer groups. Use 
metric to evaluate when it is profitable to use versus it is profitable to rent 
back.

-Actors/Stakeholders
·	IT Resource Consumers
·	IT operations DBA
·	IT operations security geek

-Assumptions
Choose a small set of hardware metrics that can be agreed to and agree on the 
cost of each. This is a suggested starting point:
·	CPU (via some published/rated amount of gridbux/CPU seconds
·	Memory occupancy (megabyte seconds?)
·	disk I/O (bytes read/written)
·	Network (bytes read/written)
·	Session occupancy (do we charge for idle time?)
A depreciation schedule has been established for every resource in the data center.
A real-dollar budget has been established for the data center.

Users are subject to a published fixed + variable pricing structure over a 
period of time (e.g., a month).
Some mechanism exists for estimating the cost of a job.

-Preconditions


-Postconditions

-Main flow of events
User A wishes to complete a job J with estimate C, which is more than A’s fixed 
budget for the month. User B has fixed budget left over for the month.
B advertises remaining fixed budget at a discount.
A subleases B’s resources for the duration of job J.
A is charged the discounted fee, which is applied to B’s costs for next month.

-Issues
A strictly pay-as-you go price model doesn’t provide any incentive to rent back.
This simplistic example doesn’t really explain why a data center would be 
interested in allowing this.
A customer may need to be able to rent the resources/budget from several 
providers to complete a single job.
What happens if A exceeds the terms of the sublease?

-Sources/references

-OGF sponsor/stakeholder/interested party

You can find many more use cases of this style in the EGA Reference Model 
documents, at http://gridalliance.org/en/workgroups/techdownloads_download.asp 
(and, eventually, coming to an OGF website near you).