soa, web service in grid computing

SOA, Web Service In Grid Computing

Phạm Hùng Tiến 00708210Đặng Hoài Đức 00708190

Agenda

Service Oriented Architecture Web Service Grid Service Open Grid Service Architecture(OGSA) Web Service Resource Framework

Service - What Is It?

An autonomous (business) system that accepts one or more requests and returns one or more responses via a set of published and well-defined interfaces

Service - An example

Restaurant provides various kinds of food (services) to its customers according to their requests.

Shopping cart Payment service Order service Checkout service

Service - What Is Service Orientation?

A business-driven “modeling strategy” that defines the business functionality in terms of loosely coupled autonomous business systems (or services) that exchange information based on messages.

Service - Tenets(1)

Boundaries Are Explicit A well-defined and published public

interface Should be easy to consume Provide fewer public interfaces Don’t expose implementation details

Service - Tenets (2)

Autonomous Services are built and deployed

independently of other services

Service - Tenets (3)

Share the Schema and Contract, Not the Class Schema = Data Contract = Behavior Services do not pass classes and types;

they pass schemas and contracts

Service - Tenets (4)

Service Compatibility Is Based on Policy Structural compatibility is based on the

contract (WSDL and optionally BPEL4WS) and the schema (XSD)

WS-Policy provides for additional, automated analysis of the service-assurance compatibility between services

SOA - What Is It?

Service-Oriented Architecture (SOA) is a mechanism that enables organizations to facilitate communication between the systems running on multiple platforms

SOA is a collection of well-defined services, each individual service can be modified independently of other services to help respond to the ever-evolving market conditions of a business

SOA - Actors

Service Provider Provides a stateless, location

transparent business service

Service Registry Allows service consumers to

locate service providers that meet required criteria

Service Consumer Uses service providers to

complete business processes

ServiceRegistry

ServiceProvider

ServiceConsumer

Find Register

Bind,Execute

SOA - Benefits

Business Benefits Focus on Business Domain solutions Leverage Existing Infrastructure Agility

Technical Benefits Loose Coupling Autonomous Service Location Transparency Late Binding

SOA - An Example

Storage Service Storing and retrieving data Reserving space, monitoring status of storage service Querying and defining the policies that govern who is

allowed access the service. Data Transfer Service

Provide operations for requesting the transfer of data from one storage service to another

Managing and monitoring such transfers Querying and defining policies that govern how

difference transfer requests are prioritized. Troubleshooting Service

SOA vs. Component-Based

The key difference is SOA provides a message-based approach based on open standards

SOA is platform independent

SOA - Advantages of Using Messaging Cross-platform Asynchronous communications Reliable communication Thread management Remote communication

Marshaling and Unmarshaling End-to-end security

Web Service

A web service is a programmable application component accessible via standard web protocols.

A Web service is a software system designed to support interoperable machine-to-machine interaction over a network

Just one kind of implementation of a service

Web Service - Key Aspects

Standard protocol HTTP, SMTP, FTP.

Service description Need to describe their interfaces in detail so that

a client knows how to “consume” the functionality provided by the service.

WSDL: Web Services Description Language. Finding services

Users need to know what web services exist and where to find them so the clients can bind to them and use the functionality.

UDDI : Universal Discovery, Description, and Integration repositories

Web Service - Protocol Stack

Web Service SOAP - Simple Object Access Protocol Lightweight communication protocol

based on XML Used to exchange structured and typed

information between systems Allows to invoke methods on remote

machines without knowing specific details of the platform or software running on those machines

Web Service - SOAP Characteristics

Extensible. Works across a number of standardized

underlying network protocols. Independent of the underlying language

or platform or programming model.

Web Service - SOAP Message Structures

SOAP Message -Sample

Method Signature int doubleAnInteger ( int numberToDouble ); Request

<?xml version="1.0" encoding="UTF-8" standalone="no" ?> <SOAP-ENV:Envelope SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance" xmlns:xsd="http://www.w3.org/1999/XMLSchema">

<SOAP-ENV:Body> <ns1:doubleAnInteger

xmlns:ns1="urn:MySoapServices"> <param1 xsi:type="xsd:int">123</param1>

</ns1:doubleAnInteger> </SOAP-ENV:Body>

</SOAP-ENV:Envelope>

SOAP Message -Sample

Response<?xml version="1.0" encoding="UTF-8" ?> <SOAP-ENV:Envelope xmlns:SOAP-ENV=http://schemas.xmlsoap.org/soap/envelope/xmlns:xsi=http://www.w3.org/1999/XMLSchema-instancexmlns:xsd="http://www.w3.org/1999/XMLSchema">

<SOAP-ENV:Body> <ns1:doubleAnIntegerResponse

xmlns:ns1="urn:MySoapServices" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/

encoding/"> <return xsi:type="xsd:int">246</return>

</ns1:doubleAnIntegerResponse> </SOAP-ENV:Body>

</SOAP-ENV:Envelope>

Web Service - Messaging Using SOAP

Application Web Service

SOAP

Network protocols (HTTP

…)

SOAP

Network protocols (HTTP

…)

Web Service WSDL-Web Service Description Language Describes Service Endpoints What are Endpoints ?

The entity that a client connects to using a specific protocol and data format when consuming a service

Web Service - WDSL: An Overview

Web Service- WDSL : An Example

Web Service - How It Works?

Agenda

Service Oriented Architecture Web Service Grid Service Open Grid Service Architecture(OGSA) Web Service Resource Framework

Grid Service - What is Grid ?

Criteria for a Grid: Coordinates resources that are not subject

to centralized control. Uses standard, open, general-purpose

protocols and interfaces. Delivers nontrivial qualities of service.

Grid Service - What Is It?

Web services that are customized to grid environment: HTTP, SOAP, XML, (G)WSDL

Grid Service vs. Web Service

Transient in Nature (Lifetime, Migration) Stateful Service

Service Data Elements (SDE) Introspection

GWSDL Vs. WSDL Standard Required Interfaces for all Services

Lifetime Management Service Data Interaction

Interfaces Predefined for common (core) Services

Agenda

Service Oriented Architecture Web Service Grid Service Open Grid Service Architecture

(OGSA) Web Service Resource Framework

OGSA – Open Grid Service Architecture

Grid Service Builds on Web Service Improves Web Service

How services are created? How long they live? How to manage faults? How to manage long-lived state?

OGSA - Core Elements

OGSA OGSI – Open Grid Service Infrastructure Grid service descriptions and instances Service state, metadata, and

introspection Naming and name resolution

Two-level naming Service life cycle Fault types

OSGAOGSI – Grid Service Descriptions and Instances

Description: gWSDL GWSDL: portType extension

<gwsdl:portType name="MathPortType“ extends="ogsi:GridService">

</gwsdl:portType> Service Data

Instance Transient Service Create Destroy

OGSA OGSI – Service Data

Standard WSDL has no formalized concept of service state

OGSI addresses these issues by defining WSDL extensions that allow for the explicit declaration of publicly visible state associated with an interface (called service data), and by defining standard operations for accessing (via both queries and subscriptions) that state

Accessing Service Data Pull Mode Push Mode( Subscription)

OGSA OGSI – Service Data

OGSA OGSI – Naming

Dynamic & Stateful Distinguish one dynamically created service instance from another Naming

Allows Grid Services to be upgraded during their lifetime (change protocol, add new protocol,…)

Two level Naming Grid Service Handle (GHS) Mapped by Handle

Resolution Service No protocol, no protocol binding, no network address Invariant

Grid Service Reference (GSR) Use to send requests Change over service’s lifetime

OGSA OGSI – Service Life Cycle

Negotiating an initial lifetime Explicit termination Requesting a lifetime modification

A client requests a lifetime modification by directing keep-alive messages

The client sends periodic keep-alive requests to indicate its continued interest in the service

What happens next?

OGSA OGSI – Service Life Cycle(cont) One of three things happens:

The transfer completes, and the file transfer service instance terminates.

The client fails, and its failure to send further keepalive messages leads to the destruction of the transfer service instance once its lifetime expires.

The client decides that it is no longer interested in the transfer and, to conserve resources, performs an explicit destroy of the transfer service instance.

OGSA OGSI – Fault Model

Define common approach for conveying fault information from operations.

Comprises a standard XSD type, ogsi:FaultType Original service Time stamp

OGSA OGSI – Service Groups

Organizing group of service instances Why?

Someone want to group service instances together

OGSA - Core Services

Address such fundamental issues Name resolution and discovery

HandleResolver interface Service domains Security Policy Messaging, queuing, and logging Events

For interoperability Metering and accounting

Collect, deliver, store, and manage information about resource usage

OGSAData and Information

Services Data naming and access Replication

Tracking, discovering, and performing replication of data resources.

Metadata and provenance Describing and tracking how data are

created Regenerate data on demand

OGSAResource and Service

Management Provisioning and resource management Negotiating between resource consumers

and resource providers for dynamic resource allocation

Service orchestration Transactions Administration and deployment

OGSA and GT3

Agenda

Service Oriented Architecture Web Service Grid Service Open Grid Service Architecture (OGSA) Web Service Resource Framework

WSRF – Web Service Resource Framework

WSRF – Web Service Resource Framework

New standard that replaces OGSI WS Resource = Web Service + stateful

resource which is used in the execution of message exchanges

WSRF

What is a WS-Resource? Examples of WS-Resources:

Physical entities (e.g.. processor, communication link, disk drive)or Logical construct (e.g.. agreement, running task, subscription)

Real or virual

Static (long-lived, pre-existing) orDynamic (created and destroyed as needed)

Simple (one), or Compound (collection)

Unique (for the Web Service) - Has a distinguishable identity and lifetime

Stateful - Maintains a specific state that can be materialized using XML

May be accessed through one or more Web Services

WSRF

A set of six standards, of which only three have been released: WS-ResourceProperties:

how a Web Service interface relates to a WS-Resource WS-ResourceLifetime

lifetime management of WS Resources WS-Notification

event subscription and notification Unreleased:

WS-RenewableReference retrieving updates of invalid endpoint references

WS-ServiceGroup heterogeneous collections of Web Services

WS-BaseFaults faults / error messages

WSRFWhy it was developed?

Criticisms of OGSI from the Web services community: Too much stuff in one spec

=> functionality partitioned into a family of composable specifications

Does not work well with existing Web services tooling => WSRF tones down the usage of XML Schema

Too object oriented: OGSI v1.0 models a stateful resource as a Web service that encapsulates the resource’s state, with the identity and lifecycle of the service and resource state coupled=> WSRF makes an explicit distinction between the “service” and the stateful entities acted upon by that service

WSRF - Resource Properties

Defines the type and values of a WS-Resource’s state that can be viewed and modified

Resource properties document acts as a view on the actual state

Described using XML Schema

WSRF - Resource Properties

GetResourceProperty GetMultipleResourceProperties SetResourceProperties

Insert,update,delete QueryResourceProperties

Using a query expression such as Xpath

WSRF – An Example

WSRF – An Example

<SOAP-ENV:Header> . . . <rpimpl:CartId wsa:IsReferenceParameter="true">S1</rpimpl:CartId>

. . . </SOAP-ENV:Header>

<SOAP-ENV:Body> <wsrf-rp:GetResourcePropertyDocument/></SOAP-ENV:Body>

WSRF – An Example

<SOAP-ENV:Body> <wsrf-rp:GetResourcePropertyDocumentResponse> <ssc:SimpleShoppingCart> <ssc:Item>

<ssc:ProductCode>Cat-A2004-87968556</ssc:ProductCode>

<ssc:Description>Garden String - 150m</ssc:Description> <ssc:Quantity>1</ssc:Quantity> <ssc:ProductPrice>1.59</ssc:ProductPrice> </ssc:Item> </ssc:SimpleShoppingCart> </wsrf-rp:GetResourcePropertyDocumentResponse></SOAP-ENV:Body>

WSRF – Other Protocols

WS-ResourceLifetime How is resource created? How is resource destroyed?

WS-Notification Event subscription and notification

WSRF and GT4

Thank you for your attention !

Q & A

References

http://docs.oasis-open.org/wsrf/wsrf-primer-1.2-primer-cd-02.pdf

http://wikipedia.org/ http://gdp.globus.org/gt3-tutorial/ http://gdp.globus.org/gt4-tutorial/ WS-ResourceProperties:

http://docs.oasis-open.org/wsrf/wsrf-ws_resource_properties-1.2-spec-os.pdf

http://www.ibm.com/developerworks/library/specification/ws-resource/

Representational State Transfer: http://en.wikipedia.org/wiki/Representational_State_Transfer