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									 OGSA/GT3 evaluation at CERN
                        Activity Report

       M. Lamanna (CERN), R. Brito Da Rocha (European Data
        Grid), Tao-Sheng Chen (Academia Sinica Taipei), A.
      Demichev (Moscow State Univ. MSU), D. Foster (CERN),
        V. Kalyaev (MSU), A. Kryukov (MSU), V. Pose (JINR
             Dubna), C. Wang (Academica Sinica Taipei)



8 December 2011          OGSA/GT3 evaluation                 1
                  Table of Content
• Introduction
• Activity highlights
     – GT3 ToolKit Experience
     – GT3 Performance studies
     – Integration of Existing Codes/Services
• Conclusions



8 December 2011       OGSA/GT3 evaluation       2
                                  Motivation
•   The promise of the web services framework
           • Standard environment for Grid applications
           • New projects are looking to OGSA as the solution to all problems…
•   Here and now
           • Globus a release of the new toolkit in May 2003.
                 –    OGSI framework and some grid services
                 –    GT3 out July the 1st (new major release -3.2- 1H04)
           • To provide input to the EGEE middleware activity
•   OGSA/GT3 project
     – Primary objectives of the OGSA/GT3 evaluation:
           •   Understand the GT3 offering and its “quality”
           •   Learn how to create new services in this framework
           •   Study how to leverage existing developments in an OGSA context
           •   Create local know-how on promising technologies
     – Most people at CERN only for short periods
           • Variable geometry approach
           • 75% of the people are not always at CERN
           • Open to new collaborators
    8 December 2011                    OGSA/GT3 evaluation                  3
 What does GT3 offer? (NOW)
• The first OGSI implementation (July 2003: 3.0.x)
     – The toolkit itself
           • Build new services and extend existing ones
     – Security Infrastructure
           • GSI (Globus Security Infrastructure)
     – Services
           • GRAM (GT2 implementation wrapped up as a Grid service)
           • IS ( Index Service; new GT3 implementation)
           • RFT (Reliable File Transfer; it uses Globus FTP)
• Explore these three lines



8 December 2011               OGSA/GT3 evaluation                     4
            Grid Service Development
•   Grid Services
       – Extended Web Services complying to the OGSI specification
              • Converge on a standard system

               HOSTING ENVIRONMENT

                      GRID CONTAINER

                                  GRID SERVICES

                          OGSI IMPL.             COMPLEMENTARY

                              WEB SERVICES ENGINE

    8 December 2011                    OGSA/GT3 evaluation       5
            Grid Service Development
•   What we get:
     – From Web Services
           • Interoperability
                 – standard for message creation and definition - XML
                 – standard for protocol-independent message passing – SOAP
                 – standard for service definition – WSDL
                     » choice on hosting environment is left to the service provider
           • Service Oriented Design approach

     – From OGSI
           • Stateful Services (Service Data)
           • Other common features on independent services
                 – Different from GT2 where nothing is common between services apart
                   from GSI
                 – Straightforward development: common framework for service usage and
                   management
    8 December 2011                  OGSA/GT3 evaluation                               6
        Grid Service Development
• Current options:
     – Hosting Environments:
           • J2EE Application Server – Jakarta Tomcat, GT3 Standalone
             Container, Websphere, …
           • Microsoft .NET Platform
     – OGSI implementations:
           • J2EE Servers: Globus Toolkit 3
           • Microsoft .NET: OGSI.NET (Virginia Univ.); MS.NETGrid
             (EPCC)
           • Others are appearing
                  – Any environment with an existing implementation of a Web
                    Services engine is one single step away from providing Grid
                    Services
                  – Ex: OGSI::Lite (Perl), pyGridWare (Python)

8 December 2011                    OGSA/GT3 evaluation                            7
           Designing Grid Services
• Important concepts when designing Grid Services:
     – Factories and Instances
                                       1
                      CLIENT                           FACTORY

                                            INSTANCE
                               2


     • Factories create instances and respond to instance creation
       requests by clients
     • Instances respond to client’s service specific interaction requests
     • Advantages:
           – Workload balancing between pools of instances
           – User dependent instances
     • Disadvantages:
           – Instance creation overhead
8 December 2011                OGSA/GT3 evaluation                     8
           Designing Grid Services
• Approach:
     – Service Data, Subscriptions and Notifications

     GRID SERVICE A          1 - SUBSCRIPTION     GRID SERVICE B

       SDE A1     SDE A2                                 SDE B1
                           2,.. - NOTIFICATIONS

  • Each Grid Service has it’s own Service Data Set - collection of
    Service Data Elements (SDEs)
  • Every SDE has a set of associated values concerning its validity
    in time – goodFrom, goodUntil, availableUntil
  • A service or client may declare interest in a SDE by issuing a
    Subscription
  • Service Data flows by means of Notifications – normally when a
     change occurs or the value lifetime has expired
8 December 2011            OGSA/GT3 evaluation                     9
                                   TestBeds
•    First hand experience on Globus Toolkit 3
      – This can be achieved only by using it!
•    The main tool are prototypes, with the following common features:
      –   Small
      –   Working (with limited functionality)
      –   No architectural ambition
      –   Engineering approach
            • Mapping of functionality – prototype functions
•    GT3 TestBed
      – 4 CERN machines + 1 in Moscow
      – Focus on GT3 basic functionality and performances
            • Performance tests use also some high performance machines and Lxplus (CERN
              Linux interactive service)
•    AliEn TestBed
      – 3 CERN TestBed machines
•    “Architecture” TestBed
      – Focus on the complexity of future possible architectures
      – Deployment use cases
    8 December 2011                    OGSA/GT3 evaluation                             10
                  Example: GT3 Test Bed
                                               ToolKit
  •   Resource broker and L&B (Custom service)
       – Surprisingly fast to set-up                                             Info Service



  •   A few computing elements (GT3-GRAM, with
                                                                                                                                        C om p.
                                                                                                                                       Elem ent


      modifications)                                                            getInfo (2)
                                                                                                             rec eiveInfo (3)
                                                                                                                                                          C om p.

Security
       – 2 PC boxes in the CERN Computing Centre
                                                                                                                                                         Elem ent




       – In a second phase, one PC located in Moscow
                                                                       Logging and
                                                                       Book keeping                                                     res erveResource (4)


         was added
                                                                                                                    Res ourc e
                                                                                                                      Broker


       – Some problems (solved) in data stage-
                                                                                                                                                          C om p.
                                                                                                                                                         Elem ent


         in/stage-out                                                                                                       res erveResource (5)



       – See GRAM comments in the performance part                                              returnTicket (6)

  •   Information service (GT3-IS)
       – Native GT3 service                                  ask Resource (1)                                                    jobSubmit (7)


       – In this TestBed talks only with other services
                                                                                                                                                   returnOutput (8)

GT3 Services
                                                                                     Us er




      8 December 2011                  OGSA/GT3 evaluation                                                                                           11
                      GT3 TestBed coverage…
PortType               Operation                      OSGA/GT3 evaluation
Gridservice            FindServiceData                •GT3TestBed-RB uses it to retrieve data from IS
 Every service                                        •IS performance tests (C-client)
 must                  SetTerminationTime             •Not Used Yet (directly)
 implement this
 PortType              Destroy                        •Everywhere, e.g. GRAM

NotificationSource     SubscribeToNotificationTopic   •IS perf. Tests (data sources)   Modelling activity of
                                                                                       this type of service
NotificationSink       DeliveryNotification           •IS perf. Tests (listener)
                                                                                       starting
Registry               RegisterService                •Code examples

                       UnRegisterService              •Code examples


Factory                CreateService                  •Via GRAM (first tests)
                                                      •Specific tests using DummyService
HandleMap              FindByHandle                   •Not Used Yet




           8 December 2011                       OGSA/GT3 evaluation                                12
             Prototypes developed within the
                         project
                                              •       Performance Prototypes
    •     Globus 3 “components” tests
                                                        – Dummy Service
            – GRAM tests
                                                        – Dummy Secure Service
            – Index Service tests
                                                        – Dummy Service with Service Data
            – Reliable File Transfer tests
                                                        – Dummy Service with Notifications
            – GSI (Security) tests
                                                        – Dummy Service + Index Service
                                                        – Index Listener
•       Implementation of deployment use
        cases
                                                  •      Higher Level Prototyping
          – Remote installation (via dedicated
             custom services)                              – File Catalog Service
          – Remote management of different                 – Metadata Catalog Service
             version of a service                          – Storage Element Service
                                                           – Workload Management Service
                                                           – Computing Element
                                                           – Authentication and Authorization
         8 December 2011                OGSA/GT3 evaluation                           13
             Globus Toolkit 3 Overview
•   The GT 3 is the first complete implementation of the OGSI specification
     – The development process is much easier when compared with GT2.
            • Steep learning curve should be taken into account!
            • New approach to service design and implementation
     –   Deployment Tools (not yet complete)
•   Backward compatibility:
     –   All GT2 components are shipped with the GT3 full bundle
     –   Others are completely independent implementations (eg. MDS2 and MDS3)
•   A large user community is being built
•   Incomplete documentation
     – But not so bad...
     – Getting much better now (tutorials, etc...)
•   Several bugs found in these exercises
            • Core implementation related - due to framework short lifetime
            • From tools deployed with the framework – hard to solve (e.g. Axis)
            • From the outside – easy to solve (e.g. Tomcat)
•   GT2 GRAM – with an OGSI-compliant but complex architecture behind
     – Worry to lose past experience (gained within the EDG and LCG projects)
     – Confirmed by performance tests (see next slides)

     8 December 2011                   OGSA/GT3 evaluation                         14
   GT3 performance measurements
            (highlights)
• Goal:
     – explore GT3 under heavy load/concurrency:
           • maximal throughput/rate of GT3 services
           • see the limiting factors
     – Other dimensions to be explored:
           •   Hardware
           •   Hosting environment
           •   Implementations
           •   Security options
• Highlights from:
     –   GRAM
     –   DummyService (test custom service)
     –   Security
     –   IndexService
     –   RFT

8 December 2011                  OGSA/GT3 evaluation   15
          GT3 GRAM performance
•        Results: service node
     –      Saturation throughput for job submission on the service node: 3.8
            jobs/minute with an average CPU user+system usage of 62%




     Comments:
           •      Very slow!
           •      Scalability issues for (heavily used) servers


8 December 2011                    OGSA/GT3 evaluation                          16
          DummyService performance
•       Setup (1)
    –     each DummyService client executes the following steps:
          1.   calls DummyServiceFactory to create a DummyService instance
          2.    executes 2 simple methods (echo and getTime) on the DummyService
               instance
          3.   calls DummyService instance to destroy itself
    –     up to 1000 clients talking to the DummyService were run
          simultaneously on up to 45 client nodes (lxplus)
    –     with and without authentication via GSI message level security used
          according to guides and tutorials at www.globus.org
    –     grid service node hardware: 2 * Intel Pentium III 600MHz
          processors, 256MB RAM

•       Setup (2)
    –     same as Setup (1), but step 2. consists of 100 cycles, each of them calling the
          2 simple methods (echo and getTime) on the DummyService instance

    8 December 2011                 OGSA/GT3 evaluation                             17
             DummyService performance
     setup     authen-          service                saturation          average CPU u+s
               tication        container               throughput             usage, %

                  no        GT3 standalone            41 services/s               89
                  yes       GT3 standalone           1.3 services/s               88
       1
                  no            Tomcat               60 services/s                89
                  yes           Tomcat               1.2 services/s               88
                  no        GT3 standalone        300 method calls/s              96
                  yes       GT3 standalone         10 method calls/s              72
       2
                  no            Tomcat            290 method calls/s              96
                  yes           Tomcat             13 method calls/s              79

•   The security overhead needs further investigation (OGSA/GT3 group and Globus)
•   The result depend on the type of security. In all tested cases, the penalty is few times a
    factor of 10
•   Some problems have been identified by the Globus team and we will test the new version
    as soon it becomes available
       8 December 2011                 OGSA/GT3 evaluation                             18
       IndexService performance
• Push setup: IndexService acting as a notification source
  (pushing data)
     – multiple notification sinks subscribe to the IndexService "Host"
       Service Data Element (SDE), and are notified about each update of
       "Host" SDE, happening at a fixed rate
     – no security
     – grid service node hardware: 2 * Intel Pentium III 600MHz processors,
       256MB RAM

• Pull setup: IndexService responding to findServiceData
  requests (pulling data)
     – multiple ogsi-find-service-data clients are run sequentially and in
       parallel asking for IndexService "Host" Service Data Element
     – no security
     – grid service node hardware: 2 * Intel Pentium III 600MHz processors,
       256MB RAM

8 December 2011               OGSA/GT3 evaluation                         19
       IndexService performance
• Results
            • No security

    setup            service                  saturation        average CPU u+s
                    container                 throughput           usage, %

                  GT3 standalone        10-15 notifications/s      81 – 87
    push
                     Tomcat                        -

                  GT3 standalone           200 requests/s             88
     pull
                     Tomcat                200 requests/s             90



8 December 2011                    OGSA/GT3 evaluation                            20
Index Service
(Information
service building
block) in push
mode

                                              Complex set up (here
                                              ~400 client processes
                                              distributed on several
                                              computers); Modelling
                                              activity required as
                                              design tool; These tests
                                              are being used to
                                              validate the first
                                              simulation prototypes




      8 December 2011   OGSA/GT3 evaluation                   21
  Reliable File Transfer Service
• Emphasis on reliability. Solve problems like e.g.
   – dropped connections,
   – machine reboots,
   – temporary network outages, etc
• Functionality: OK
• Main problem: resource hog
• Comprehensive report submit to Globus
• Fix found by the GT3 team
    – Functionality tests on the new version OK (it ships with 3.2 a)
    – We agreed to test it in detail
• Open chapters
    – gridFTP performances (the RFT “engine”)
           • WU-FTP and the new globusFTP



8 December 2011               OGSA/GT3 evaluation                       22
                         Integration
•       GRID mainly concerns about the interoperability
        among heterogeneous grid components
•       Heterogeneous Grid environments
          – AliEn (Alice Environment; LHC ALICE experiment)
              • Should provide first-hand experience within LCG
•       Heterogeneous Grid technologies (non GT3)
          – OGSI .NET, MS .NETGrid (.NET environment)
          – Unicore, others…
          – Discussion with some teams at GGF9; to be restarted end
            of November (after SC2003)
•       Necessary to validate GT3 itself!

    8 December 2011          OGSA/GT3 evaluation                  23
   Do not lose the “past” experience
• Assessment of OGSA/GT3
         • Strategy defined in coordination with embryonic EGEE teams
           (last August)
   – EDG
         • Major issue so far: GRAM and Information Service
   – LCG deployment
         • Major issues so far: GRAM, Information Services and
           configuration issues
   – VDT
         • CondorG/GT3 becoming available
         • Agreement to use it in our test
   – eScience gap analysis (Geoffry Fox report)
         • Used to inform the original evaluation plan

 8 December 2011              OGSA/GT3 evaluation                   24
                     Relationship building:
                       Globus Toolkit 3
• Contact with the GT3 team
   – Little formalities, working relationship
   – We acknowledge the good relationship with GT3 team
• Status of the interactions:
   – Access to unreleased software; agreed mechanisms to discuss and give
     feedback
   – Job Gatekeeper (GRAM)
        • Feedback
        • More priority on performances inside the GT3 team since
   – Reliable File Transfer (RFT)
        • Issues (high CPU consumption) confirmed. Fix available
        • Access to the experimental trunk for verification
   – Index Server (IS)
        • Several issues being discussed; 3.2 IS available
   – Security (GSI)
        • Issues being discussed; fix available soon


   8 December 2011                OGSA/GT3 evaluation               25
                       Conclusions
• Much progress has been made in a short time…
• Generally impressed with GT3 and the overall concept
• Some major issues around the performance of the hosting
  environments and the factories
   – Continue closely working with Globus
• Continue to validate this approach and prototype interfaces
  and services in a GT3 context
   – Be able to hand over a consistent picture to EGEE
• Continue to take into account use cases / valuable information
  from any source
   – EDG, LCG,
   – HepCAL, ARDA
   – …


 8 December 2011            OGSA/GT3 evaluation                 26

								
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