1. GridLab WP-2 Cactus GAT (CGAT) Ed Seidel, AEI & LSU Co-chair, GGF Apps RG, Gridstart Apps TWG Gabrielle Allen, Robert Engel, Tom Goodale, *Thomas Radke Others from WP-1

2. WP2 Vision Goal: enable all Cactus apps to use GAT for Grid scenarios. Very important WP, prototyped in first year, now being fully developed as GAT implementation in first full release Cactus (http://www.cactuscode.org) Leading application framework used by dozens of groups in astrophysics (EU Network), climate, CFD, numerical relativity, bio- informatics Used for many years for in (pre)Grid environments, and is commonly deployed for demonstrations of the use of the Grid Previously used hand-crafted Cactus modules, ad-hoc mechanisms, relying on the authors' extensive experience of Grid computing The CGAT work aims to replace this using functionality available through the GAT API Exemplar: modules for other Cactus apps, worked example for others

3. WP2 Dynamic Grid Computing Migration: “Cactus Worm” demonstrated SC00 Launch Job Run awhile, write checkpoint Migrate itself to next site Register new location to User tracks/steers Proof of concept, but dirty hack Created our community! Spawning: SC01 User invokes “Spawner” Analysis tasks outsourced Globus enabled login, data transfer It worked!

4. WP2

5. CGAT Conceptual View Thorn CGAT consists of a set of “thorns”, linked to GAT Engine, which provide services to Cactus applications. The vast majority of Cactus thorns will be unaware of the CGAT or GAT. Cactus Flesh GAT GridLab Service GridLab Service Application Thorns

6. WP2 CGAT Functionality Ability to remote trigger app checkpoint, retrieve checkpoint file, and stage it to a new host Provide performance and other data to external applications using GAT monitoring infrastructure. Export list of application-created files via GAT advert and/or replica functionality, through generic advertising service Query information about the current machine, such as cache size, memory size, size of file-systems, name of machine. Spawning of tasks, e.g. for task farming, monitoring status. Automated/triggered announcement of app events, such as app startup, reaching particular iteration, termination, etc. Etc: Working with app communities to determine need: GGF, Gridstart TWG, other projects

7. WP2 Status SC03: thorns were written with prototype GAT Engine to enable the GridLab migration scenario: Remote monitoring of the status of the running Cactus application Triggering of Cactus checkpointing Advertisement of Cactus checkpointing data Now: thorns converted to use the new GAT implementation and the specified GAT API Will be demonstrated at this review and at GGF this week Any application in Cactus can take advantage of this without any other modification E.g., Black Holes on regular meshes, CFD on unstructured meshes (planned), ocean-atmosphere modeling

8. WP2 Some Specifics Gridmake: https://sourceforge.net/projects/gridmake/ Distribute/compile source code on an arbitrary number of machines Needed for GridLab migration, Cactus remote testing, creation of executables for MPI simulations across multiple machines Good for codes with configurable make environments, machine configuration scripts, use of CVS etc. Developed using public key infrastructure, soon as a grid service To be incorporated as a GridSphere portlet Thorn_cgat Initializes GAT Registers that this is checkpointable app with grms Receives requests from grms (or any broker) Steers cactus parameter to initiate checkpoint Reports on success of checkpoint

9. WP2 Near Future Review current thorns, make production versions, distribute Add remaining functionality Work with AEI/LSU numerical relativity group ensure correct functionality train on use of CGAT infrastructure develop task farming infrastructure for physics surveys Deploy across GridLab testbed and LSU-AEI-KISTI Grid Work with other Cactus app groups in astrophysics, climate, CFD, bioinformatics, others; NSF and DOE projects in US New, experienced personnel just added now that GAT ready