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Globus Toolkit. Massimo Sgaravatto INFN Padova. Introduction. Grid Services: LHC regional centres need distributed computing Analyze toolkits that integrate distributed computational resources: Globus Legion Globe …. Globus. Basic research on GRID problems Globus Toolkit
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Globus Toolkit Massimo Sgaravatto INFN Padova
Introduction • Grid Services: LHC regional centres need distributed computing • Analyze toolkits that integrate distributed computational resources: • Globus • Legion • Globe • …. 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 Massimo Sgaravatto
Local Services Condor MPI TCP UDP LSF Easy NQE AIX Irix Solaris Globus Architecture Applications High-level Services and Tools GlobusView Testbed Status DUROC MPI MPI-IO CC++ Nimrod/G globusrun Core Services Nexus GRAM Metacomputing Directory Service Globus Security Interface Heartbeat Monitor Gloperf GASS 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) (???) 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 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) 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) Massimo Sgaravatto
Globus Resource Manager Architecture Application Resource and Job specification (High level RSL expression) MDS RSL specialization Broker Resource discovery Create jobs (Ground RSL expressions) GRAM GRAM GRAM CONDOR LSF fork Site1 Site2 Site3 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 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 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 Massimo Sgaravatto
Use Case: CMS HLT studies 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 Massimo Sgaravatto
Other problems • Documentation not well organized • Collaboration with HPC Lab, University of Lecce is very useful ! Massimo Sgaravatto