OGSA

Hauptseminar: Data GridThema 2: Open Grid Service Architecture

Vorträger: Lu xin

...Everything is service...

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OGSA History Announced at GGF4 (’02/2) Work Group created (’02/9) 6 interim F2F meetings OGSA Usecase document at GGF10 (’04/3) Declared as GGF’s flagship architecture at

GGF10 (’04/3) OGSA document at GGF11 (’04/6)

First version as informational documentCompanion OGSA Glossary document

What is OGSA?

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Open service-oriented architecture based on Web services for addressing Grid scenarios Component-oriented architecture

Interchangeable components Meta OS functionalities

Distributed and heterogeneous environment A rendering of these functions, based on

Web service architecture and specifications

Foster:

GOAL

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Realization of the modern computing environment:

Discovered Allocated Accessed

MonitoredAccounted forBilled for

etc…

The components can be in general managed as a single virtual system

Manage resources across distributed heterogeneous platforms. Deliver seamless quality of service (QoS). Provide a common base for autonomic management solutions.Define open, published interfaces.Exploit industry standard integration technologies.

Concept & Consensus

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keyword:Grid Service

“ Open Grid Service Architecture suppose a concept called Grid Service, it puts heavy emphasis on the concept of “services”. ”

“ The emergence of OGSA represent s a consensus on the standardization of resource accessing interfaces as grid services”

keyword:Standardization

InterfacesService Data

Everything is represented as a Grid service. All components of the environment are virtualized.

OGSA Architecture

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OGSA Architecture

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Layers:

Grid applications

OGSA architected services

Web services+the OGSI extensions that define grid servicesDiscovery >> UDDI (Universal Description, Discovery & Integration)

Description >> WSDL (Web Services Description Language), XML..

Invocation >> SOAP (Simple Object Access Protocol)

Transport >> HTTP (HyperText Transfer Protocol)

Resourcesphysical resources and logical resources

ServiceRegistry

ServiceProvider

ServiceRequestor

Find Publish

Bind

WDSL UDDIWS-Inspector

SOAP

Service Oriented Architecture

overview

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Client X

Client X

Client X

Virtual StorageFactory

Physical storageVirtual storage

What is happened here??

Just like web service??

Grid Service

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Stateful and potentially transient services Useful for the Clain Operations(realy?)

Typical Web Service

Grid Service

based on Web Service

Grid Service

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Service Data Service Statedata(opertaion

result, runtime infos..) Service Metadata(introspection ) Service Data Element (SDE)

Name Type (XML type) Extensibility attributes

Lifetime declarations Application-specific

Extensibility elements Service data value Application-specific

Service Data Set A set of SDEs Each Grid Service must have e

xactly one service Data Set Accessible in two ways:

FindServiceData Notification

Lifecycle management Instance can be created and

destoried at any time

Grid Service Example

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Service Data in WSDL

<wsdl:definitions xmlns=“…” targetNamespace=“…”> <gwsdl:portType name=“StorageService”

extends=“gsdl:GridService”> <wsdl:operation name=getFile> … </wsdl:operation> <sdf:serviceData name=“capacity” type=“xsd:integer”/> <sdf:serviceData name=“lifeTime” type=“xsd:integer”/> <sdf:serviceData name=“lastResult” type=“xsd:integer”/> <sdf:serviceData name=“location” type=“xsd:string”/> <sdf:serviceData name=“speed” type=“xsd:integer”/> <sdf:serviceData name=“freeSpace” type=“xsd:integer”/> <sdf:serviceData name=“accessControlPolicy” type=“tns:PolicyType”/> … </gwsdl:portype></wsdl:defintions>

Grid Service

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Interface --- portType extension all Grid Services must extend from a standard portType called GridService FindServiceData

Input QueryExpressionType: query mechanism used QueryExpression: actual query

Output Result of Query

SetTerminationTime Request that termination time of this service be changed Input: client timestamp and new termination time Output: service timestamp and current termination time

Destroy Explicit destruction request

Grid Service Example

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<portType name="GridServicePortType"> <operation name="findServiceData"> <input message="tns:FindServiceDataInputMessage"/> <output message="tns:FindServiceDataOutputMessage"/> <fault name="QueryNotSupportedFault" message="ogsa-faults:QueryNotSupportedFault"/> <fault name="InvalidQueryFault" message="ogsa-faults:InvalidQueryFault"/> </operation> <operation name="setTerminationTime"> … </operation> <operation name="getTerminationTime"> … </operation> <operation name="destroy"> … </operation></portType>

<portType name="Database_PortType" extends “gsdl:GridService”> <operation name="databaseQueryOperation"> <input message="tns:myDatabaseQuery"/> <output message="tns:myDatabaseResponse"/> </operation></portType>

Grid Service Functionality

Database_PortTypeInherits from GridService

Grid Service

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Messaging SOAP(web service) Defines the message used in operation

Notifications Dynamic monitoring

very closely related to service data Service must implement a notificationSource interface. Client must implement a notificationSink interface.

Grid Service

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GSH & GSRglobally Unique URLidentifies the instance for all timeLocation of the Grid Service only

Resolves GSH into GSROptionally, the client can do it by itselfInterface: FindByHandl

•Input: GSH & unsatisfactory GSRs•Output: GSR

FactoryCreateService()

Input: TerminationTime ServiceParameters (specific to a service)

Output: ServiceTimestamp information & Service Locator (to get GSH)

many different forms (WSDL…)Possible to communicate with Grid Service

&

Grid Service Example

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UserApplication

BioDB n

Storage Service Provider

MiningFactory

CommunityRegistry

DatabaseService

BioDB 1

DatabaseService

.

.

.

Compute Service Provider...

DatabaseFactory

Grid Service Example

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UserApplication

BioDB n

Storage Service Provider

MiningFactory

CommunityRegistry

DatabaseService

BioDB 1

DatabaseService

.

.

.

Compute Service Provider

“I want to createa personal databasecontaining data one.coli metabolism”

.

.

.

DatabaseFactory

Service Deployment

WDSL

Definition

Grid Service Example

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UserApplication

BioDB n

Storage Service Provider

MiningFactory

CommunityRegistry

DatabaseService

BioDB 1

DatabaseService

.

.

.

Compute Service Provider

“I want to createa personal databasecontaining data one.coli metabolism”

.

.

.

DatabaseFactory

Find Mining Service,

Database Service

GSH

Grid Service Example

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UserApplication

BioDB n

Storage Service Provider

MiningFactory

CommunityRegistry

DatabaseService

BioDB 1

DatabaseService

.

.

.

Compute Service Provider...

DatabaseFactory

m_instance

d_instance

“Create a data mining service with initial lifetime 10”

“Create adatabase with initial lifetime 1000”

GSH

GSH

Grid Service Example

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UserApplication

BioDB n

Storage Service Provider

MiningFactory

CommunityRegistry

DatabaseService

BioDB 1

DatabaseService

.

.

.

Compute Service Provider...

DatabaseFactory

m_instance

d_instance

Query

Query

Results

Notifikation

Notifikation

GSH

Grid Service Example

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UserApplication

BioDB n

Storage Service Provider

MiningFactory

CommunityRegistry

DatabaseService

BioDB 1

DatabaseService

.

.

.

Compute Service Provider...

DatabaseFactory

d_instance

m_instance

Notify me, if complete

Make WS Stateful

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OGSA requires 'stateful services‘

WSRF WSRF extends Web Services Developed by OASIS

Grid Service

based on Web Service

Review: Useful for the Clain Operations(realy?)

WSRF: It's all about state

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WSRF: It's all about state

WSRF: It's all about state

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WSRF = Web Service+Resource

The WSRF specification

WS-ResourceProperties A resource is composed of zero or more resource properties

•Filename, Size, and Descriptors…

WS-ResourceLifetime Resources have non-trivial lifecycles

WS-ServiceGroup groups of Web Services & groups of WS-Resources

WS-BaseFaults standard way of reporting faults when something goes wrong during a WS-

Service invocation

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Related specifications WS-Addressing

we can use WS-Addressing to address

a Web service + resource pair (a WS-Resource).

WS-Notification notification producer

notification consumers

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Architecture Review

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Architecture Review

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References

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The Open Grid Services Architecture, Version 1.0 -- http://forge.gridforum.org/proj

ects/ogsa-wg

The Physiology of the Grid -- Ian Foster, Carl Kesselman, Jeffrey M. Nick, Steven Tuecke

OGSA Rising, -- Ian Foster, Argonne National Laboratory

Grid Services Overview, -- Keith R. Jackson, Distributed Systems Department, Lawrence Berkeley National Lab

The Grid Enabling Resource Sharing within Virtual Organizations, -- Ian Forster

http://http://gdp.globus.org/gt4-tutorial/ -- Tutorial from globus

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Danke