[Pgi-wg] Definition of a Production Grid

[Laurence Field]

Dear All,

The word Grid means different things to different people and this quite 
frequently leads to misunderstandings and conflict. This is especially 
true within OGF where people from many different domains and backgrounds 
discuss "Grids".  While each and every definition themselves are as 
valid as each other, trying to discuss a concept from two possibly 
unrelated perspectives is quite difficult.

Before we move forward in the PGI activity we therefore need understand 
what we mean by "Grid" and hence the problem we are trying to solve.  It 
seems that in some recent threads the word "production" has cause some 
disagreements as this word is more commonly used to reflect quality 
rather than concepts.

 From my perspective I can try to define the core properties that I see 
are key when describing the EGEE infrastructure. I would hope that 
similar infrastructures with whom EGEE would like to interoperate would 
have a similar description.

I would like to introduce the term "Muti-institutional infrastructures 
for e-Science" which can be used to describe something with the 
following properties.

1) Multi-institutional.
The EGEE infrastructure is composed by linking resources that reside at 
autonomous academic institutes. The key concept here is the 
administrative domain which maps to a real institute and that there is 
more than one institute in the infrastructure.

2) The Virtual Organization
The main aspects that links these institutes is the drive to collaborate 
in order to do science. The collaborations are defined by Virtual 
Organizations.

3) x509 Certificates and Proxies
Users are identified by x509 certificates which are provided by CAs 
accredited by the IGTF. Proxies are typically used to interact with 
services.

4) VOMS
To identify which VO a user is belong to is by contacting VOMS. VOMS 
also supports Roles an Groups within the VO which is implemented by 
adding attributes to the proxy.

5) Multiple Services
The are many different types of services each of which can define their 
own interfaces which may or many not be a Web Service.

6) Parrallel Information System
The information about services is found by querying an information 
system which is not necessarily related to the service interface.

6) Scale
100s of administrative domains, thousands of users, thousands of 
services, millions of computing actives and petabytes of data.
 
This may be a can of worms but if we can agree on a set of properties 
for what we mean by "Production Grid" it might help in the discussions. 
I don't mean that anything that has different properties is not a 
production grid, I just want to clarify what this group mean when it 
talks about a Grid infrastructures.

Laurence


Laurence