1. Some ideas for the future
WP1 Meeting
Milano, 11th September 2001

2. Overview
Complex jobs
Dependency on Condor
Use of existing frameworks

3. Complex Jobs: Definition
A complex job is a set of jobs with dependencies among them.
Dependencies are temporal and are given, for example, by I/O requirements.
subjob B needs as input the output of subjob A
The definition is very vague and generic.

4. Complex Jobs: (initial) Assumptions
Dependencies are not cyclical
Otherwise subjobs have to execute concurrently (co-allocation problem)
The definition is not recursive
A subjob cannot be a complex job
Otherwise the semantics of a dependency is more complicated

5. Complex Jobs: Example A B F C D E
The complex job can be represented as a Direct Acyclical Graph (DAG)

6. Complex Jobs: Simple Solution
Represent a DAG with a nested ClassAd (?)
“Linearise” the DAG
for the example: A C D B E F
use a “topological sort” algorithm
the solution is not unique
For each subjob send it to the Resource Broker independently
Data representing a dependency is saved in a “temporary” and “anonymous” file

7. Complex Jobs: Other Issues
Job identifiers
Interaction with LB
What to do in case a subjob fails
Various types of dependencies

8. Dependency on Condor
In my opinion we should get rid as soon as possible of our dependency on those parts of Condor which will not likely become Open Source (TM)
Starting with Condor-G
job submission is not particularly difficult directly on top of Globus
job monitoring should be done based on info in the LB

9. Implementing ComputingElement
Implemented the ComputingElement interface directly on top of Globus, so that one can do:
ComputingElement ce(“pcfg.cnaf.infn.it”);
Job job;
job.set_attribute(“executable”, “/bin/sleep”);
job.set_attribute(“arguments”, “10”);
ce.submit(job);
ce.cancel(job);

10. Using Existing Frameworks
We should evaluate and possibly adopt existing (OO) application frameworks, instead or reinventing the wheel
there was a comment on this from one of the D1.2 reviewers
One possibility is the Adaptive Communication Environment (ACE) (