grid services vs web services n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Grid services vs. Web services PowerPoint Presentation
Download Presentation
Grid services vs. Web services

Loading in 2 Seconds...

play fullscreen
1 / 34

Grid services vs. Web services - PowerPoint PPT Presentation


  • 106 Views
  • Uploaded on

Grid services vs. Web services. Dana Petcu , Georgiana Macariu, Marc Francu, Alexandru Carstea IeAT, Romania. Content. Grid ws. Web services Similarities What is different? Overview of the SCIEnce activities at Timisoara. Similarities. Special forms of distributed computing

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Grid services vs. Web services' - ryo


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
grid services vs web services

Grid services vs. Web services

Dana Petcu, Georgiana Macariu,

Marc Francu, Alexandru Carstea

IeAT, Romania

content
Content
  • Grid ws. Web services
    • Similarities
    • What is different?
  • Overview of the SCIEnce activities at Timisoara
similarities
Similarities
  • Special forms of distributed computing
  • Both typically deal with wide-area distributed computing
  • A Grid service is basically a Web service with some additions
    • E.g. to make it able to store state information persistently rather than transiently at the server beyond the lifetime of a single request
differences
Differences
  • Grid services have different goals from pure Web services:
    • WS: conceived to share information, (eg: http://www.webservicesx.net/globalweather.asmx
    • GS: conceived to share computing power and resources like disk storage databases and software applications (eg: EGEE)

“Grid service = Grid computing + Web services”

  • Every Grid service “is a” Web services, but not every Web service “is a” Grid service
web service
Web service
  • A software system built to support communication between two processing elements that are interconnected through a network
  • The most important requirement: interoperability
  • Interaction client-service provider is carried out using XML based messages
  • Messages are exchanged using an underlying protocol such as HTTP or SMTP.
  • A web service offers an interface described by a document that can be processed by a machine in automatic fashion
  • Use SOAP standard or REST standard
    • REST standard imposes that a request must specify all the information needed by the server to service the request (no stateful information should be kept at server level)
    • For SOAP standard the interface is defined using WSDL
grid services extends web services by
Grid services extends Web services by:
  • stateful services,
  • service instantiation,
  • named service instances and a two-level naming scheme,
  • a base set of service capabilities, including discovery facilities,
  • lifetime management
statefulness
Statefulness
  • An instance of a service is stateless if it cannot remember prior events.
  • An instance of service is stateful if it can remember about prior actions (-> vars. within service to maintain vals between accesses)
  • A WS is usually stateless, A GS is stateful
  • A WS can be stateful using ad hoc methods
  • Grid services are bringing uniformity and consistency in this topic
statefulness1
Statefulness
  • State in the Web service is generally regarded as a bad thing!
  • Stateless Web services storing state information? By separating the Web service from the state information!
  • State keep it in a separate entity called resource
  • Each resource has a unique key
  • Statefull interaction with a Web service: instruct the Web service to use a particular resource.

Web Service + Resource = WS-Resource

slide10
Web services - stateless vs. stateful : bank service analogy(from www.neresc.ac.uk/events/presentations-talks/WebGridServices.pdf)
instantiation
Instantiation
  • WS: no different discrete units of state (instances) named in a consistent manner
  • GS:
    • namable state
    • GS specification defines:
      • Factories and
      • Lifetime management services
    • A factory implements an operation that creates a new service instance and returns its handle and its initial termination time.
named service instances
Named service instances
  • WS: named by URIs
  • GS:
    • named at a first level by a Grid Service Handle (GSH) - an URI, an abstract name that refers only an instance (no information like the location, implementation, or status of the service)
    • A GSH is resolved at a second level into a Grid Service Reference (GSR)
from www cs indiana edu ysimmhan l talks simmhan b534 2004 pdf
From: www.cs.indiana.edu/~ysimmhan/l/talks/simmhan-b534-2004.pdf

GSH = http://extreme/services/foo/my-service

GSR (URL) = http://ooty:8080/foo-service

My Grid Service

Invoke method on service

4

GSH = http://extreme/services/service-registry

GSR (URL) = http://rainier:20202/service-registry

GSH = http://extreme/services/handle-resolver

GSR (URL) = http://rainier:10101/handle-resolver

Service Group

Registry

Handle Resolver

SDE:

<entry>

<locator>

<handle>http://extreme/services/foo/my-service</handle>

</locator>

<content>

<foo>myContent</foo>

</content>

</entry>

Get GSR for registry GSH

http://extreme/services/service-registry.

Returns http://rainier:20202/handle-resolver

1

2

3

Get all Entries about services.

Returns Metadata Content and the GSH (http://extreme/services/foo/my-service)

Select your service and get GSR for GSH

http://extreme/services/foo/my-service. Returns http://ooty:8080/foo-service.

Client

Handle Resolver URL = http://rainier:10101/handle-resolver

Your Service Handle = http://extreme/services/foo/my-service

OR locate from Registry GSH = http://extreme/services/service-registry

service discovery
Service discovery
  • WS: UDDI registry, allow introspection and discovery of static information such as service interfaces and associated policy
  • GS: need support for transient service instances that are created or destroyed dynamically!
  • GT4
    • uses an own index service which locate service based upon user criteria
    • service discovery is based on Service Data Elements (SDEs) = a structured collection of information associated with a Grid service that allows a user to choose a service that satisfies its needs, e.g. functionality speed, cost.
lifecycle
Lifecycle
  • related to the issues of resource reclamation associated with services in the event of
    • failures (eg. loss of network connectivity)
    • or lack of interest by any relevant clients (eg. service no longer ref. by any active process)
  • WS: cycle controlled by the Web Server
    • dynamically allocated when a request arrives
    • deallocated when that request/session ends
  • GS:
    • set a time (in SDE) when a service will self-destruct unless kept alive by subsequent increases in its termination time
    • service instance need not to be explicitly destroyed
transient vs non transient service
Transient vs. non-transient service
  • A transient service instance is one that can be created and destroyed (eg. for specific clients)
  • An non-transient (persistent) instance of a service outlives its client
  • WS: usually non-transient
  • GS: can be
    • stateful transient:
      • an instance assigned to each client and only that client can access stored information;
      • information retained between accesses and pertains to the client;
      • instance usually destroyed when its purpose has been fulfilled
    • stateful non-transient:
      • several clients share one instance of the service,
      • Stored information is available to all clients.
current standards
Current standards
  • GT4 and WSRF.NET currently implements Web Services Resource Framework (WSRF) that specifies stateful WS that extends WSs
  • WSRF: a collection of specifications
      • WS-ResourceProperties
      • WS-ResourceLifetime
      • WS-ServiceGroup
      • WS-BaseFaults
      • [WS-Notification]
      • [WS-Addressing]
references
References
  • M.C. Brown, Build grid applications based on SOA. Concepts behind SOA and how to move grid applications to SOA model, DeveloperWorks -- IBM's resource for developers, 2005, www-128.ibm.com/developerworks/grid/library/gr-soa/
  • A. Grimshaw, Grid services extend Web services, SOAWebServices Journal 506, 2003, webservices.sys-con.com/read/39829.htm.
  • D.Petcu, Between Web and Grid-based Mathematical Service, Procs. ICCGI, IEEE Computer Society Press, 2006, science.ieat.ro/science/research/publications/
  • K. Champion, Stateless and stateful WS in the Grid community, 2004, searchwebservices.techtarget.com/expert/KnowledgebaseAnswer/
  • P. Shread, Web Services a Good Start For Grid, But Not Enough, Grid Computing Planet, 2003, www.gridcomputingplanet.com/news/article.php/3281_1571191
  • B. Sotomayor, Globus Toolkit 4 Programmer's Tutorial, gdp.globus.org/gt4-tutorial
  • H. Stockinger, Grid Computing: A Critical Discussion on Business Applicability, IEEE Distributed Systs Online,vol.7,no.6,2006, dsonline.computer.org/portal/site/dsonline
  • WSRF, http://docs.oasis-open.org/wsrf/
science activities at timisoara

SCIEnce activities at Timisoara

http://science.ieat.ro

slide21
JRA1
  • Access to Grid and Web services
  • Service discovery
  • Facilitate the creation on Grid symbolic services
activities
Activities
  • A tool for accessing services from a CAS

Novelty:

    • Automatic creation of Grid/Web clients
    • Generic for any CAS
  • Overviews papers:
    • Identify state of the art
  • Research: propose some improvements for CAS related to Grids
slide23
API
  • In the next talk…
  • Now only some test interface

API Exercise: http://194.102.62.36/portal

papers http science ieat ro science research publications
Papers (http://science.ieat.ro/science/research/publications/)
  • D. Petcu, D. Tepeneu, M.Paprzycki, T.Ida, Symbolic Computations on Grids, chapter 6 in "Engineering the Grid: status and perspective", eds. Beniamino di Martino, Jack Dongarra, Adolfy Hoisie, Laurence Yang, and Hans Zima, American Scientific Publishers, 2006, pp. 91-107
  • D. Petcu, Improving Computer Algebra Systems by Using Grid Services, in 1st Austrian Grid Symposium, J. Volkert, T. Fahringer, D. Kranzlmuller, W. Schreiner (eds.), Austrian Computer Society, Band 210, 2006, 102-110
  • D.Petcu, C.Bonchis, C.Izbasa, Symbolic Computations based on Grid Services, Int. Journal of Computers, Communications and Control (RO), Vol. 1, no. 1, 2006, 44-50
  • D.Petcu, Between Web and Grid-based Mathematical Services, ICCGI, 1-3 August 2006, IEEE Computer Society Press, eds. P. Dini, C. Popoviciu, C. Dini, Gunter Van de Velde, E. Borcoci
  • D.Petcu, Mathematics on the net: state of the art and challenges, 8th French-Romanian Colloquim on Applied Mathematics, Chambery, France, August 28-31, 2006, invited talk