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Globus III - Information Services

Globus III - Information Services. Resource Discovery. Critical in a grid to be able to discovery what resources are available and what are the options. For compute resources, information can be hardware details and software details, and dynamically changing information such as load.

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Globus III - Information Services

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  1. GlobusIII - Information Services Grid Computing, B. Wilkinson, 2004

  2. Resource Discovery • Critical in a grid to be able to discovery what resources are available and what are the options. • For compute resources, information can be hardware details and software details, and dynamically changing information such as load. Grid Computing, B. Wilkinson, 2004

  3. Typical Details • Compute resources: • CPU vendor, type, speed, cache sizes, ... • Memory type, size, speed, ... • Disk space … • Network resources • Network bandwidth • Latency • Topology • Protocols, ... Grid Computing, B. Wilkinson, 2004

  4. Compute Resource Software Details • IP address • Software available • Operating System version number • Resource manager, ... Grid Computing, B. Wilkinson, 2004

  5. Static and Dynamic data • Information is always subject to change and old. • Some information changes naturally, such as load information. Grid Computing, B. Wilkinson, 2004

  6. Centralized Information System Resources Clients “push” LDAP Server Clients query for current information Periodically update LDAP server information LDAP Lightweight Directory Access Protocol Grid Computing, B. Wilkinson, 2004

  7. Disadvantages • Does not scale well as number of resources grows • Commercial LDAP services optimized for read operations, not good with frequent writes. • System fails if LDAP server down Grid Computing, B. Wilkinson, 2004

  8. Globus Grid Information ServiceMonitoring and Directory Service (MDS) • Based upon LDAP. • Originally called “Metacomputing Directory Service” - renamed • MDS-2 uses a distributed organization. Grid Computing, B. Wilkinson, 2004

  9. MDS-2 Consisting of two types of service: • Grid Resource Information Service (GRIS) • Grid Index Information Service (GIIS) Grid Computing, B. Wilkinson, 2004

  10. Grid Resource Information Service (GRIS) • Associated with each resource. • Answers queries from client/user about the particular resource. • Accesses an “information provider” deployed on that resource for requested information. Grid Computing, B. Wilkinson, 2004

  11. Queries • “White pages” • Resource information • e.g. How much memory does machine have • “Yellow” pages • Resource options • e.g. Which queues allow large jobs. Grid Computing, B. Wilkinson, 2004

  12. Grid Index Information Service (GIIS) • A directory service that collects (‘pulls”) information for GRIS’s. • A “caching” service. • Provides indexing and searching functions. Grid Computing, B. Wilkinson, 2004

  13. Overall Structure Resources Clients GRIS Clients query resource GRIS directly for current information GIIS information as needed “pull” Clients makes indirect query to GIIS GRIS GIIS Grid Computing, B. Wilkinson, 2004

  14. Scaling • Can have multiple GIIS’s in various configurations • Configuration can take into account virtual organizations Grid Computing, B. Wilkinson, 2004

  15. Accessing Information GT3 command: grid-info-search with various flags to specify host, port, etc.: -h MDS server -p MDS port -b Search start point -T LDAP query time out Grid Computing, B. Wilkinson, 2004

  16. Example grid-info-search -x -h hot.mcs.anl.gov -p 2135 -b “Mds-Vo-name=local, o=Grid” Produces: dn: Mdss-Host-hn=hot.mcs.gove, Mds-Vo-name=local, o=grid Mds-CPU-speedMhz: 866 Mds-Memory-Ram-Total-freeMB: 304 Mds-CPU-Free-5minX100: 134 . . From “Grid Computing” by A. Abbas, page 204. Grid Computing, B. Wilkinson, 2004

  17. LDAP Browser/Editor • Java Commodity Grid (CoG) Kit has a LDAP Browser/Editor Grid Computing, B. Wilkinson, 2004

  18. LDAP Browser/Editor From “Grid Computing” by A. Abbas, page 202. Grid Computing, B. Wilkinson, 2004

  19. Security • MDS 2.1 has PKI security for GSI mutual authentication Grid Computing, B. Wilkinson, 2004

  20. LDAP Exercise • Go to Globus subdirectory called ldap • Follow instructions in README file Grid Computing, B. Wilkinson, 2004

  21. Discovering Grid Services • MDS, as described, is only for discovery hardware resources, not the actual grid services one might want. • In a service oriented architecture, services are “published” in a registry so that they can be found. Grid Computing, B. Wilkinson, 2004

  22. Service-Oriented Architecture Service registry 1. Publish 2. Find 3. Bind Service requester Service provider Grid Computing, B. Wilkinson, 2004

  23. UDDI(Universal Description, Discovery, and Integration) • Web services often use UDDI registries. • UDDI designed to support business services. • Information can be classified as: • White pages -- company contact information, ... • Yellow pages -- Web service description • Green pages -- Technical information about Web Service Grid Computing, B. Wilkinson, 2004

  24. Web Services From http://www.globus.org Grid Computing, B. Wilkinson, 2004

  25. Accessing Grid Services • GT 3 provides an “index service” (as a higher level service) to access service data provided with grid service. • Service data can includes both hardware and software details of service. Grid Computing, B. Wilkinson, 2004

  26. GT3 Index Service From “Grid Computing” by J. Joseph and C. Fellenstein, page 340. Grid Computing, B. Wilkinson, 2004

  27. Service Data • Information about service provided in service data elements (SDEs) as part of the GWSDL file. • The GWSDL file defines service interface (see assignment 2), and SDEs are added to this. Grid Computing, B. Wilkinson, 2004

  28. Types of Service Data Elements • State Information -- results, previous results, run time information, … • Service Metadata -- system data, supported interfaces, cost of using service, ... Grid Computing, B. Wilkinson, 2004

  29. Client Accessing Service Data • Done through grid service methods. Grid Computing, B. Wilkinson, 2004

  30. Changes to Grid service • Done through “notification” mechanism whereby client subscribes to mechanism and is notified of changes. Grid Computing, B. Wilkinson, 2004

  31. addListener to subscribe notifyChange when change occurs deliverNotification to notify subscribers Derived from The Globus Toolkit 3 Programmer’s Tutorial” by Borja Sotomayor, 2004, page 65. Grid Computing, B. Wilkinson, 2004

  32. More Information • “The Globus Toolkit 3 Programmer’s Tutorial” by Borja Sotomayor, 2004, Chapter 5 and Chapter 6. http://www-unix.globus.org/toolkit/ Gives sample code. Grid Computing, B. Wilkinson, 2004

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