Ian,
We did not disregard the comment at all. It
was discussed at length in
The attention to WS-Names in BES – i.e.,
the use of EPR’s with an explicit decoration of an element called
AbstractName of type URI/IRI perplexes me. The URI/IRI is close to a free
form string – with no internal structure being mandated whatsoever. Adding
another element to an XML structure is simple (the X stands for extensible). Presumably
Globus uses some information in the EPR to identify in some way the endpoint
service being referenced by an EPR. What WS-Names do is give the client a way
to determine if two EPR’s “point” to the “same” endpoint.
Constructing the AbstractName can be trivial – concatenate the string
elements that are currently being used to identify the endpoint.
Andrew
From: owner-
Sent: Wednesday, October 26, 2005
1:44 PM
To: Andrew Grimshaw; 'Darren
Pulsipher';
Subject: RE: [ogsa-bes-wg]
Proposed changes to Spec.
Andrew:
We should ask the OGSA-WG to speak definitively on the first issue, as there
seems to be confusion among participants as to what the policy means.
Regarding OGSA-BES's use of WS-Name: I appreciate the information on the
decision procedure.
More generally, I guess this exchange reflects a common tension between the
relative importance of the views of "insiders" vs.
"outsiders" in GGF WGs. I know that quite a few people (myself
included) started off wanting to engage as insiders in OGSA-BES, but after
various unsatisfactory interactions (e.g., discussions like this one, where the
response to a concern is to be told that it will be disregarded), ended up
becoming outsiders. The OGSA-BES is of course free to work as it wants, but excluding
the views of so many people also greatly reduces the likelihood that whatever
specifications OGSA-BES produces will be widely adopted.
I don't understand the discussion of events: I didn't speak to eventing in my
email, but about the right way of specifying the activities to which an
operation should apply.
Regards,
Ian.
At 01:05 PM 10/26/2005 -0400, Andrew Grimshaw wrote:
Ian,
My understanding of the OGSA policy is that OGSA does not
mandate WS-Names & instead it encourages them WHERE THEY ARE APPROPRIATE.
That decision is up to individual working groups, and perhaps a design team
working on a profile. The policy, in my mind, is NOT that WS-Names may not be
mandated by OGSA specifications.
In the case of OGSA-BES, at the last GGF in
Thus, OGSA-BES will have* WS-Names as return values and input
parameters.
We also discussed eventingat some length. I have not yet
typed in my notes, the three high order bits were:
1) The container is the right place to emit the events
2) Clients must explicitly subscribe to events (use filtering from the
container, not specific registration& Im not sure what that means, I think
we will need to discuss this in a call and remind me.)
3) Events are state transitions of the activities
Andrew
*Of course the document still has to go into public comment,
get revised, and hopefully some day be approved by the GFSG. What is really in
the document may change between now and then.
From: owner-
Sent: Wednesday, October 26, 2005
11:40 AM
To: Darren Pulsipher;
Subject: Re: [ogsa-bes-wg]
Proposed changes to Spec.
Darren:
I would like to argue against your proposed operations on the grounds of
fragility and scalability. Your operation definitions require that a
client keep track of the set of activities to be monitored and controlled.
That's a big burden to place on the client.
I suggest (as we have also suggested in earlier communications to BES-WG) that
we should instead allow the user to specify a set of activities that are to be
monitored or controlled in terms of their properties, not names. E.g.,
"activities that belong to me", "activities that involve
executable Foo", "activities that have been running for over 2 hours."
A natural way of modeling this is to represent the set of activities associated
with your jobs as a WS-ServiceGroup Service Group, and then use queries on the
service group to specify the activities to which an operation applies.
Regards -- Ian.
PS: As noted in previous emails and conversations, I also believe that the use
of WS-Names rather than vanilla EPRs is inappropriate. I also believe that it
is inconsistent with the OGSA policy that WS-Names cannot be mandated in
OGSA-related specifications.
At 08:52 AM 10/26/2005 -0600, Darren Pulsipher wrote:
I have spent some considerable time with the document.
I know far more than I planned, but it was good time spent.
I think we should discuss these items in our meeting on Thursday.
I have posted some changes to the document but would like to discuss
these items before I make these changes to them.
There are some fundamental problems/questions that we need to resolve.
1. How do we resume from where we left off. There is no Resume anymore
so we are putting the responsibility to the submitter or controller to
keep track of states. We can only use RequestActivityStateChanges to
suspend something and if I want to suspend 1000s of activities that
means I would need to first do a GetActivityState save the states and
then call RequestActivityStateChanges without any of the activities
changing state. That is not going to happen. So I propose we do the
following:
- Add the following interfaces:
SuspendActivites(WS-Name[] activityIdentifiers)
ResumeActivities(WS-Name[] activityIdentifiers)
Or we add one interface
PerformOnActivites("Suspend" | "Resume", WS-Name[]
activityIdentifiers)
2. Another problem is how do we terminate an activity. The States that
are available are "Terminated" and "ShuttingDown". According
to the
state net the activity is moved to the "ShuttingDown" and then to
"Terminated" so requesting RequestActivityStateChanges for activities
with "ShuttingDown" means it should move to the ShuttingDown state
but
it will move the activities to the "Terminated" state. This can be
very
confusing. So I suggest we add another interface.
- Add the following interface:
TerminateActivities(WS-Name[] activityIdentifiers)
Or add another possible argument to the interface.
PerformOnActivites("Suspend" | "Resume" |
"Terminate", WS-Name[]
activityIdentifiers)
3. Another question that is not clear in the spec is if an action
(staging in or staging out) moves into an exception state does that mean
that the activity moves into the exception state right away or does it
mean that it ever moves into the exception state. Does it mean that if
one of the actions moves into an exception state that all other actions
are halted and moved to the exception state and then the activity?
- I proposed that actions state have no impact on the activity state. If
an action has an exception or is terminated then it should not have any
impact on the activity what so every.
4. Another not so important change but it might help clarify some
confusion and allow for extendibility later on would be to get rid of
the "ExecutionPending" and "ExecutionComplete" and make the
"Running"
state a composite state like the "StagingIn" and
"StagingOut" states.
This will give the ability to handle complex multiple application
execution definitions that the JSDL group is looking at for the next rev
of the Job Definition. This will allow for multiple Application actions.
This is not workflow. Nor should it be considered the start of workflow.
This just allows for extendibility easily.
Darren Pulsipher
_______________________________________________________________
Ian
Foster
www.mcs.anl.gov/~foster
Math & Computer Science Div. Dept of
Computer Science
Argonne National Laboratory The
Tel: 630 252
4619
Fax: 630 252 1997
Globus
Alliance, www.globus.org
Math & Computer Science Div. Dept of
Computer Science
Argonne National Laboratory The
Tel: 630 252
4619
Fax: 630 252 1997
Globus
Alliance, www.globus.org