20040323 - Targets discussion.

["Gary Cole" <Gary.Cole@waveset.com>]

I think that the following fairly represents the common ground we
reached in the discussion of "Targets" on today's call, but I may have
overlooked something important.
If so, please point out the omission.

1) What is a Target?
   - A Target represents a choice of something to provision 
     (e.g., an application or a service).
   - A Target is not necessarily the actual, physical target.
     (A PSP translates a request for an application or service 
     into operations against physical targets as necessary.)

2) Multiple targets per PSP?
   - A PSP may expose multiple targets in the most general case.
     (A "white box" PSP allows the RA to request provisioning to a
specific target,
     and may allow RA to specify a target for individual operations.)
   - Some PSPs may expose no target.
     (A "black box" PSP doesn't offer any choice.
     The PSP decides what you get, and you may never know exactly what
you got.)

3) How might SPML reflect targets?
   - A PSP would provide an operation to 'listTargets'.
     (A "black-box" PSP might list one target or no target at all.)
   - Target identifier would be an optional parameter to operations.
     (If no target is specified, the operation applies to all targets.)

4) What attributes would a target have?
   - NAME: meaningful to PSP.  String (could be URN or whatever).  
     (Common sense suggests that target name should be unique within
PSP.)
   - DESCRIPTION: optional string.  Intended to be meaningful to human
user of RA
     (or to human configuring automation of RA).
   - SCHEMA: optional.  Target may need schema to be useful in some
contexts.


Several additional issues were raised.

5) Should any "master record" (e.g., a template of a provisioned object)

   that the PSP maintains be represented as a target?
   - It is the privilege of the PSP to present the master record 
     (or virtual identity) as a target if it so chooses.  
   - However, this is not necessary (given our current understanding)  
     since any operation that is not qualified with a target identifier
     would apply to all targets (and thus to the master record). See #3
above.

6) Other aspects of the ObjectModel may be equally (or more) important
than Target.
   - Agreed that other aspects of the object model deserve discussion,
     and that importance depends greatly on one's point of view.
   - We began by discussing Target because PST is discussed in the 1.0
spec,
     because some of us believe that target is fairly fundamental,
     and because we had to start the discussion somewhere. 

Gary