1. Bridging WSRF services and the EGEE middleware Process Management
Pedro Andrade CERN, Geneva
(on behalf of the University of Basel team)

2. Outline Process Design and Verification
Process Execution and Reliability
Process Optimisation
GT4
gLite
09/11/2018

3. Process Design and Verification
GUI for specification of processes:
Loading/editing/storing of process specifications
Specify transactional behavior
Browse the DIS for the activities (services) composing the process
Processes verification:
Syntax and semantics check
Execution only accepts approved specifications
Specify transactional behavior... e.g. alternative execution paths
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A process is composed of activities
09/11/2018

4. Process Execution and Reliability
Responsible for the compond service execution
Dynamically select “best nodes“ for the execution of process activities
Using Process Optimisation
Control of the execution is moved to the target node of the current activity
Failure-handling
If transactional guarantees provided, rollback or execute alternative paths
09/11/2018

5. Process Optimisation Optimisation: Pre-planning (before execution):
Re-ordering of activities
Parallelising as much as possible
Pre-planning (before execution):
For processes with short expected runtime
Using the global knowledge of the process specification
Annotate each activity with the “preferred“ nodes for execution
Matchmaking (at runtime):
For process with long expected runtime
Using local knowledge only (self + successors)
Look for the best nodes for the successor activites
09/11/2018

6. GT4 The following WSRF and WSN specifications are used:
WS-ResourceProperties
WS-ResourceLifetime
WS-Base-Notification
WS-BaseNotification
WS-Topics
09/11/2018

7. GT4
Only the Process Execution and Reliability service is WSRF and WSN compliant
Each running instance of a process is represented by a UUID
Each node taking part in the execution of that process instance creates a WS-Resource with that UUID
The process execution coordination requires this service to implement brokered notification through the DIS
A Universally Unique Identifier is an identifier standard used in software construction, standardized by the Open Software Foundation (OSF) as part of the Distributed Computing Environment (DCE). The intent of UUIDs is to enable distributed systems to uniquely identify information without significant central coordination. Thus, anyone can create a UUID and use it to identify something with reasonable confidence that the identifier will never be unintentionally used by anyone for anything else. Information labelled with UUIDs can therefore be later combined into a single database without need to resolve name conflicts. The most widespread use of this standard is in Microsoft's Globally Unique Identifiers (GUIDs) which implement this standard.
A UUID is essentially a 16-byte number and in its canonical form a UUID may look like this:
550E8400-E29B-11D4-A
09/11/2018

8. gLite
gLite Wrapper: WSRF service which integrates gLite jobs into processes
Each job is represented by a WS-Resource. The ResourceProperties contain information about:
JDL (passed as input parameter to the service)
Job ID
Status number
Status message (can be updated during job execution)
Job output (?)
WS-Notification is triggered by status changes:
If clients are subscribed
The client is asynchronously notified
09/11/2018

9. Questions ?? Thank you !!! http://www.diligentproject.org
09/11/2018