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gLite Information System(s )

gLite Information System(s ). Daixiang Mu Peking University.  Interconnection & Interoperability of Grids between Europe and China . Outline. Overview LCG Information System Architecture and Levels A LDAP Model R-GMA Introduction R-GMA Server Architecture Virtual Database

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gLite Information System(s )

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  1. gLite Information System(s) Daixiang Mu Peking University Interconnection & Interoperability of Grids between Europe and China 

  2. Outline • Overview • LCG Information System • Architecture and Levels • A LDAP Model • R-GMA • Introduction • R-GMA Server Architecture • Virtual Database • Producer • Consumer • Query examples • R-GMA Server • R-GMA user interfaces • References

  3. Overview • Collect information of grid resources • Discovering new added resources • analyzing usage and performance of the Grid • Publish these information • Periodically updated • Used by • Users searching a concrete resource • WMS allocating and managing jobs • Other monitoring services

  4. Overview • Basic data model. • Grid Laboratory Uniform Environment (GLUE) Schema. • Two architectures in glite3 • LCG Information System • BDII over Globus MDS(Monitoring and Discovery Service). • implementation of LDAP(specialized database optimized for reading, browsing and searching information). • Preserves LCG-2 compatibility. • Relational Grid Monitoring Architecture (R-GMA) • implementation of the GMA standard from the Grid Global Forum • Information in SQL relational databases • Web Services. • Future replacement of LCG IS.

  5. LCG Information System

  6. Architecture and Levels

  7. Architecture and Levels Resource level: GRIS (Grid Resource Information Server) • Runs on top of each CE, SE, RB, MyProxy (no WNs) • collects information about all resources statically or dynamically • Use command $ ldapsearch <option> to query GRIS directly Site level: GIIS (Grid Index Information Server) • Runs on top of each site • collects information about all resources coming from all the GRISes • LCG-2 recommends using a BDII instead of a GIIS to increases the stability • Also use command $ ldapsearch <option> to query GIIS directly

  8. Architecture and Levels Top level: BDII (Berkeley DB Information Index) • Stores information from local BDIIs or GIISes in its database • by querying the BDII a user or a service has all the available information • Only queries sites that are included in a configuration file • Easily decide which information they desire publish and automatically exclude sites that presents temporary problems

  9. A LDAP Model • Way of collecting info • Pull model (higher level servers periodically query lower level servers) • Inherit hierarchical structure (tree-like) • Users get info with • Querying IS elements info with lcg-infosites or lcg-info, enough for most common user needs • Get information about specific resources (maybe more up-to-date) by querying directly the site BDIIs, GIISes or GRISes with command ldapsearch

  10. Relational-GMA

  11. Introduction • Developed as part of the EuropeanDataGrid Project (EDG) • Now as part of the EGEE project. • Based the Grid Monitoring Architecture (GMA) from the Global Grid Forum (GGF).

  12. R-GMA Server Architecture

  13. Grid Monitoring Architecture • Producers register themselves with the Registry and describe the type and structure of information they want to make available to the Grid. • Consumers query the Registry to find out what type of information is available and locate Producers that provide such information. • Once this information is known the Consumer can contact the Producer directly to obtain the relevant data. Registry Producer Consumer

  14. Virtual Database R-GMA share information in a virtual database which consists of a list of table definitions (called a schema), a list of data providers (called a registry).

  15. Producer Producers are the data providers for the virtual database, There are three types of producer: Primary, Secondary and On-demand. Queries Queries User code ProducerAPI Producer Service User code ProducerAPI Producer Service Consumer Consumer Control and inserted tuples Control only Tuples Tuples Primary Secondary Tuple Storage Tuple Storage Other Producers

  16. Producer • In the On-demand Producer, there is no internal storage; data is provided by the user code in direct response to a query forwarded on to it by the producer service. • On-demand producer are optimized to answer simple queries quickly. • The primary purpose of an On-demand producer is to allow large databases to be accessed through the R-GMA infrastructure, without the overhead of copying tuples. On-demand Queries Queries Tuples User code ProducerAPI Producer Service Consumer Control only Tuples User code

  17. Consumer There are four types of query: • Continuous: as soon as new data becomes available it is broadcast to all interested parties. • Latest: correspond to intuitive idea of current information. • History: return time sequenced data. Queries Queries User code Consumer API Producer Service Producers Tuples Tuples Comsumer Tuple Storage Registry Service

  18. Query examples • The Consumer will get all the URLs that could satisfy the query. • The Consumer will connect to all the Producers. • Producers that can satisfy the query will send the tuples to the Consumer. • The Consumer will merge these tuples to form one result set. Registry Producer 1 Producer 2 Consumer

  19. Query examples

  20. Query examples SELECT Service.URI Service.email Contact FROM Service S, Service Status SS where(S.URI= SS. URI and SS.up=‘n’)

  21. R-GMA Server • R-GMA Servers • Server :one or several • Schema Server :There is one common global schema server for the grid • Registry Server: one or several • Browser: shows grid information via web browser • R-GMA Clients • Generic Client : generic set of APIs for different languages and CLIs) • Servicetool : used by all services to publish its existence and status • Site Publisher • Client to publish the existence of a site. • Each site must have one R-GMA site publisher. • GadgetIN (GIN) • Client to extract information from MDS and to republish it to R-GMA. • used by the CE. • Data archiver :flexible archiver • Client to make the data that is coming from the R-GMA site-publisher, servicetool and GIN constantly available. • By default the GLUE tables and service tables are archived, however this can be configured.

  22. R-GMA Server The gLite R-GMA Server should deployed the first as part of a gLite grid, because all services require it to publish service information.

  23. R-GMA user interfaces https://rgmasrv.ct.infn.it:8443/R-GMA

  24. References • GLUE Schema • http://glueschema.forge.cnaf.infn.it/ • LCG-2 User Guide • https://edms.cern.ch/file/454439//LCG-2-UserGuide.html • gLite 3.0 User Guide • https://edms.cern.ch/file/722398/1.1/gLite-3-UserGuide.pdf • R-GMA home page • http://www.r-gma.org/ • R-GMA in EGEE • http://hepunx.rl.ac.uk/egee/jra1-uk/

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