Grappa

1
Grappa

• Provide a point of access to ATLAS grid resources
• Collaborative effort, part of GriPhyN
• Indiana
• Northwestern
• Boston
• Components
• Resource selection
• User interface
• Job submission
• Monitoring
• Bookkeeping

2
The ideal GRAPPA

• provides a simple interface for physicists to
  submit and monitor jobs on the Grid
• is compatible with Athena architecture
• is compatible with whatever Reference Grid
  Architecture is adopted by ATLAS
• The Anatomy of the Grid (Foster, Kesselman)
• Data Grid architecture
• is adaptable and/or extensible to new
  developments in Grid software, and Athena

3
Per The Anatomy of the Grid the following
layers make up the Grid architecture

• Application
• calls upon services defined at ANY layer.
• Collective
• captures interactions across collections of
  resources. For example, resource discovery by
  type, load, or availability.
• Resource
• builds upon connectivity layer to allow secure
  initiation, monitoring, and control of
  INDIVIDUAL resources. Resource layer protocols
  call Fabric layer functions to access and control
  local resources --includes both resource state
  information gathering and negotiation of access
  to the resource.
• Connectivity
• defines communication (between Fabric layer
  resources) and authentication protocols required
  for Grid-specific network transactions.
• Fabric
• is the logical or physical resources to which
  shared access is mediated by Grid protocols.

Other terms Protocol defines how distributed
systems interact with one another to achieve a
specified behavior, AND the structure of the
information exchanged during this
interaction. Service defined by the protocol it
speaks AND the behavior it implements
4
Based on this model, GRAPPA proposes to offer the
following via a one-stop front end

• collect authentication information from the user
  and communicate with the connectivity layer to
  gain access to and communicate with Grid
  resources
• communicate with the collective layer to present
  the user with a list of appropriate Grid
  resources or automatically make a best-choice
  selection based on user-specified requirements
  entered in the GRAPPA front end
• communicate with the application layer to fill-in
  where the application has not yet been
  Grid-enabled, and/or present information from the
  Grid-enabled portion of the application via the
  GRAPPA front end
• communicate with the resource layer to initiate
  usage of specific Grid resources and proceed to
  display monitoring information via the GRAPPA
  front end
• communicate with the inquiry and resource
  management mechanisms implemented by the fabric
  layer to put/get files, monitor processes, etc.

5
Application
GRAPPA
Collective
Resource
Connectivity
Fabric
6
Progress

• Several organizational meetings between CS and
  physics
• Scenario documents for ATLSim and Athena
  developed
• ATLSimGlobus submission prototype complete

7
GRAPPA Today

• is web based
• uses grid software
• Globus
• Active Notebook (Indiana Computer Science Dept.
  http//www.extreme.indiana.edu/an/index.html)
• executes ATLSim jobs
• Provides bookkeeping

8
Notebook Database

• A flat tree of documents
• Associate control scripts, job output and web
  pages for a given run
• Each time a user submits a job, the system
  creates a page which records the script, and
  the output from the script execution

9
User authenticates with globus credentials
10
User can have multiple Notebooks
11
...and multiple sessions (runs) within a
Notebook
12
In this example, a parameter file is generated
and saved on the host where execution will occur.
13
Then the job is executed with user supplied
command line parameters. For remote execution
GRAM is used
14
Parameters are automatically stored under the job
name for future use
15
Future plans...

• Incorporate existing tools for resource discovery
• Store user annotations with job metadata
• Display redirected stdout and stderr
• Stage input files with GSIftp
• Integrate Condor
• Interface with Athena Python scripting
• Interface with PPDG Job description language
• http//lexus.physics.indiana.edu/griphyn/grappa