1. 1 Peter Allan14-15 Dec 2004AstroGrid Consortium Meeting: Architecture Discussion AstroGrid Architecture – the view from outside Is the description acceptable? Is the architecture accurate? Is the architecture wrong? What can usefully be added? Are there things in the architecture (or implementation) we want changed for linking in applications? Starlink / IDL (Solarsoft) / anything else Top level overview http://astrogrid.ast.cam.ac.uk/architect ure-itn6/document/ Workflow and job orientation http://astrogrid.ast.cam.ac.uk/architect ure-itn6/document/job- orientation.html Common Execution Architecture http://astrogrid.ast.cam.ac.uk/architect ure-itn6/document/cea.html MySpace http://astrogrid.ast.cam.ac.uk/architect ure-itn6/document/MySpace.html

2. 2 Peter Allan14-15 Dec 2004AstroGrid Consortium Meeting: Architecture Discussion Issues from Visitors session Workbench Interaction with astronomer’s own programs Resource allocation Checkpoint for complex jobs Dealing with complex objects Interface to other VO’s What needs to be installed to support X? Documentation Data publishing

3. 3 Peter Allan14-15 Dec 2004AstroGrid Consortium Meeting: Architecture Discussion Portal / Workbench Problems with multiple users using Portal? Commercial software can impact architecture Should look at AVS / Triana / Taverna Issue of links between processes being more complex in AstroGrid than current systems Portal needs to keep pace with the workbench Developing the GUI is hard work So even if we don’t use Triana or Taverna, can we pinch the GUI part? Part of architecture, but could have impact if we import something

4. 4 Peter Allan14-15 Dec 2004AstroGrid Consortium Meeting: Architecture Discussion Astronomer’s own programs Felt to be vital to support astronomer’s own programs CEA does allow this Where are the problems?  GUI  User input  File format conversion Work from Opticon on importing programs Clear interfaces are the key Need to call VO functions from own code Architectural implications depend on what is required

5. 5 Peter Allan14-15 Dec 2004AstroGrid Consortium Meeting: Architecture Discussion Resource Allocation Need to prevent users from swamping the system runaway programs Give priority to local users (?) Need to set maximum time allowed for a workflow Or a job step? Just like traditional batch computing Not in current architecture AAA mentioned as something to be done

6. 6 Peter Allan14-15 Dec 2004AstroGrid Consortium Meeting: Architecture Discussion Checkpoint for complex jobs Need a way to preserve partially completed jobs so don’t need to re-run from scratch If a job step has started running and JES tries to restart it on a different system, must tell first one to cancel it Not in current architecture

7. 7 Peter Allan14-15 Dec 2004AstroGrid Consortium Meeting: Architecture Discussion Dealing with Complex Objects Example of a web service that returns several images and pieces of metadata How to handle such things in workflow? How to handle data objects with complex, self describing structure? Time series

8. 8 Peter Allan14-15 Dec 2004AstroGrid Consortium Meeting: Architecture Discussion Interface with other VO’s Need to ensure we can interact with other VO’s Is this just ensuring that we accept each other’s credentials Shibboleth X.509 certificates Already part of architecture

9. 9 Peter Allan14-15 Dec 2004AstroGrid Consortium Meeting: Architecture Discussion What needs to be installed to support X? Example Department X has installed a 10TB file system and wishes to make it available for local users for MySpace Issue Should be clear which components need to be installed to support this Should be a reasonable subset Architectural issue, but may be ok.

10. 10 Peter Allan14-15 Dec 2004AstroGrid Consortium Meeting: Architecture Discussion Documentation General lack of documentation that an astronomer needs to start using AstroGrid Not an architectural issue Data publishing Need documentation on how to publish data through AstroGrid Could be an architectural issue if the architecture prevented data being published in the way needed