1. Globus Toolkit Massimo Sgaravatto INFN Padova

2. Massimo Sgaravatto Introduction Grid Services: LHC regional centres need distributed computing Analyze toolkits that integrate distributed computational resources: Globus Legion Globe ….

3. Massimo Sgaravatto Globus Basic research on GRID problems Globus Toolkit “Bag of services” for developing GRID tools and applications Available for most Unix platforms Limited functionalities for Win32

4. Massimo Sgaravatto Globus Architecture Applications Core Services Metacomputing Directory Service GRAM Globus Security Interface Heartbeat Monitor Nexus Gloperf Local Services LSF CondorMPI NQEEasy TCP SolarisIrixAIX UDP High-level Services and Tools DUROCglobusrunMPINimrod/GMPI-IOCC++ GlobusViewTestbed Status GASS

5. Massimo Sgaravatto Core Services Security (GSI) Information Service (MDS) Resource Management (GRAM) Remote Data Access (GASS) Communication (Nexus) Network Performance Monitor (GLOPERF) Fault detection (HBM) Executable Management (GEM) (???)

6. Massimo Sgaravatto Globus Security Infrastructure Main focus: authentication single authentication not necessary to manage authentication on each GRID node Mapping between GRID user-id and local user-id Digital signature mechanisms

7. Massimo Sgaravatto Metacomputing Directory Service Static and dynamic information about GRID components (host architecture, memory, load, network bandwidth, latency....) Possibility to define new attributes Information updated by: Globus services (i.e. GRAM Reporter) Users/Applications Other “providers” (i.e. SNMP) Tools and API for discovering, publishing, and accessing information Standard protocol and interface: LDAP Single MDS server (located in USA)

8. Massimo Sgaravatto Resource Management Management of computational resources GRAM (Globus Resource Allocation Manager) responsible for a set of “local” resources Single interface to different resource managers (Condor, LSF, NQE, fork,...) Resource Specification Language (RSL) for defining: resource requirements (machine type, memory,...) job definition (executable, parameters,...) I.e.: & (ResourceManagementContact = “cond.pd.infn.it:/C=US/.../CN=cond.pd.infn.it- condor”) (count=100) (executable=myapp)

9. Massimo Sgaravatto GRAM CONDOR Globus Resource Manager Architecture Application Broker MDS GRAM LSF GRAM fork Resource and Job specification Resource discovery Create jobs (Ground RSL expressions) Site1 Site2Site3 (High level RSL expression) RSL specialization

10. Massimo Sgaravatto Remote Data Access GASS (Global Access to Secondary Storage) Supported servers: GASS, HTTP, FTP Uniform naming using URL: I.e.: x-gass://host1.pd.infn.it:1234/filename Possibility to access remote data sets (distributed file system) Necessary to modify source code: open()  globus_gass_open() close()  globus_gass_close() Caching Possibility to move files from/to remote data storage systems

11. Massimo Sgaravatto Other core services Nexus Unicast and multicast low level communication library Supports different programming models (message passing, RPC, etc…) HBM (Heartbeat Monitor) Monitors the status of registered processes GLOPERF (Globus Network Performance Measurement Tool) Measures throughput and latency between node pairs

12. Massimo Sgaravatto Evaluation of the Globus Toolkit 5 sites Testbed (Bologna, CNAF, LNL, Padova, Roma1) Use case: HLT CMS studies MC Prod.  Complete HLT chain Services Resource management fork()  Interface to different local resource managers (Condor, LSF) Resources chosen by hand  Broker to implement a Global resource manager Data Mover to stage executable and input files to retrieve output files

13. Massimo Sgaravatto Use Case: CMS HLT studies

14. Massimo Sgaravatto Status Globus installed on 5 Linux PCs in 3 sites GSI Seems working MDS Lots of problems, maybe temporary? GRAM, GASS, Gloperf, HBM Work in progress

15. Massimo Sgaravatto Other problems Documentation not well organized Collaboration with HPC Lab, University of Lecce is very useful !