9th Lecture COP 4991 Component-Based Software Development Instructor: Masoud Sadjadi sadjadi/Teaching/ Developing Grid Services

9th Lecture

COP 4991 COP 4991 Component-Based Software DevelopmentComponent-Based Software Development

Instructor: Masoud Sadjadihttp://www.cs.fiu.edu/~sadjadi/Teaching/

Developing Grid Services Developing Grid Services on LA Gridon LA Grid

9th Lecture 2COP-4991: Component-Based Software Development

AcknowledgementAcknowledgement

Fernando Ferfan Mayelin Felipe Borja Sotomayor Lisa Childers


OUTLINEOUTLINE

WEB SERVICES FUNDAMENTALS GRID FUNDAMENTALS OGSA, WSRF & GT4 DEVELOPING WS IN LAGRID

– Unsecured Examples– Secure Examples


Web ServicesWeb Services Designed to support interoperable machine-to-machine interaction

over a network. Uses a previously described interface (WSDL). Communicates using messages via HTTP enclosed in a SOAP

envelope. Allows intercommunication amongst different platform and/or

programming languages. OASIS and the W3C responsible for the standardization of web

services. WS-I established to improve interoperability.

Jonatan Alava

SOAP (Simple Object Access Protocol)WSI - Web Services Interoperability OrganizationOASIS (organization), the Organization for the Advancement of Structured Information Standards, a global consortium that develops data representation standards for use in computer software.WSDL ws description language----------------According to the W3C a Web service[1] is a software system designed to support interoperable machine-to-machine interaction over a network. It has an interface that is described in a machine-processible format such as WSDL. Other systems interact with the Web service in a manner prescribed by its interface using messages, which may be enclosed in a SOAP envelope, or follow a RESTful approach. These messages are typically conveyed using HTTP, and normally comprise XML in conjunction with other Web-related standards. Software applications written in various programming languages and running on various platforms can use web services to exchange data over computer networks like the Internet in a manner similar to inter-process communication on a single computer. This interoperability (for example, between Java and Python, or Microsoft Windows and Linux applications) is due to the use of open standards. OASIS and the W3C are the primary committees responsible for the architecture and standardization of web services. To improve interoperability between web service implementations, the WS-I organization has been developing a series of profiles to further define the standards involved.


WEB SERVICES AdvantagesWEB SERVICES Advantages

Web Services are platform and language independent.

Most Web Services use HTTP for transmitting messages.

Web services can be combined to provide an integrated service.


WEB SERVICES DisadvantagesWEB SERVICES Disadvantages

Overhead – transmitting messages in XML

Lack of versatility - not as many features as other distributed computing technologies


Typical Web Service Typical Web Service InvocationInvocation

The Globus Toolkit 4 Tutorial.http://gdp.globus.org/gt4-tutorial/


Detailed Web Service Detailed Web Service InvocationInvocation



Server SideServer Side

handles HTTP messages

provides a 'living space' for applications that must be accessed by different clients

handles SOAP requests and responses



stateless vs. stateful web stateless vs. stateful web serviceservice

Stateless web services don’t “remember” information from one invocation to another whereas stateful Web Services do.

When Web Services are used just to create Internet-based applications with loosely coupled clients and servers, they can be stateless. The service can be restarted without concern of previous interactions.

When Web Services are used to create Grid Applications, they are generally required to be stateful.


Stateful web services exampleStateful web services example

Buyer Amazon.com

login

login ok, your shopping cart id is 0x800

logout

login and my id is 0x800

Your shopping cart has …


ProblemsProblems

No standard on how to do this Client needs to have special code Some protocol specific features like cookies can be used


OUTLINEOUTLINE




WHAT’S A GRID ANYWAYS?WHAT’S A GRID ANYWAYS?

GRID SYSTEM: A system that …– Coordinates resources that are not subject to centralized control.– Using standard, open, general-purpose protocols and interfaces.– To deliver nontrivial qualities of service.

GRID COMPUTING: The field of computing science which concerns with Grid Systems.

A GRID: an actual, working Grid system (i.e. LAGrid).

THE GRID: Accessible to the general public, in the same sense that The Internet is publicly accessed.


Grid ServicesGrid Services

So, what are these grid services? Grid services are web services that are customized to grid

environment Similar to web services they provide the glue to interact

with heterogeneous systems Why do we need them? What do they provide?


Achieving StatefulnessAchieving Statefulness

The state is kept in a separate entity called a resource. Each resource has a unique key.



What do you think are the tradeoffs of providing the state explicitly within the request message or maintaining the state implicitly within system components with which the web service can interact?

Web service could maintain the resource identity as static service state, thus obviating the need to pass that identity in the WS-Addressing endpoint reference.

This design choice implies a one-to-one mapping from Web service endpoints to stateful resources and thus a need for a unique Web service endpoint for each stateful resource.

Achieving StatefulnessAchieving Statefulness


Web Services vs. Grid Web Services vs. Grid ServicesServices

Though web services are great, some key things that are required on the grid are missing– State management– Global Service Naming– Reference resolution– more …


Web Services vs. Grid Web Services vs. Grid ServicesServices

Wait a minute ! I can do all those things with web services, can’t I?

YES ! You can But,

– The standards don’t provide (yet) the required mechanisms. Work is being done to figure out the best way to do these things


OUTLINEOUTLINE




OGSA IntroductionOGSA Introduction Grid systems and applications aim to integrate, virtualize and manage

resources and services within distributed, heterogeneous, dynamic “virtual organizations”

Items needed– Computers, application services, data, and other resources need to be

accessed within different organizations– Standardization

Open Grid Services Architecture (OGSA) Is a service-oriented architecture (SOA), that addresses the

need for standardization by defining a set of core capabilities and behaviors that address key concerns in Grid systems

SOA: A perspective of software architecture that defines the use of services to support the requirements of software users. Enables the creation of applications that are built by combining loosely coupled and interoperable services

wikipedia.com


OGSAOGSA

OPEN GRID SERVICES ARCHITECTURE (OGSA)– VO Management Service.– Resource Discovery and Management Service.– Job Management Service.– … security, data management, etc.


– OGSA is the architecture, OGSI is the infrastructure.

– Grid service interface standard Methods allow access to Grid

service As well as Grid service state

(SDE)– Optional factory interface– Naming and referencing of Grid

services– Extends WSDL 1.1 (GWSDL)– Handle resolver– Notifications

Grid Service Handle (GSH) Publish GSR

Bind

Service Consumer

Client

Service Provider

Grid Service

OGSI Registry

Grid Service Reference(GSR)

Legendrequest flow

reply flow

program boundary

module boundary

Reply

Grid Service Reference

OGSI Grid service locator:•Multiple GHSs + GSRs + interface description

Open Grid Service Infrastructure (OGSI) Open Grid Service Infrastructure (OGSI) - 2001- 2001


Grid Services as seen by OGSIGrid Services as seen by OGSI

Connect to the grid service Ask the server to create an instance for you Get a unique global pointer to it Interact with the service


OGSI IssuesOGSI Issues

Confusion and Criticism from web services folks Modeling stateful resource with Web services Web service Resource Framework (WS-RF) 2004


WSRFWSRF

Stands for Web Services Resource Framework Improves on the concept of Web Services by creating a

separate view for the resource state. Simplifies WSDL and reduces message size and

complexity (XML gets heavy and complicated fast) Modular (users decide which specification to use)

Jonatan Alava

WSRF is also a haitian radio station here in South FloridaXquery and tigerlogic XML servers


WS-ResourceWS-Resource

Provides a means of expressing the relationship between stateful resources and web services

The WS-Resource has an XML resource property document defined using XML schema.

The requestor can determine the WS-Resource type by retrieving the portType

Web service programming paradigm is used to interact with the resource


* www.globus.org/wsrf

OGSI WSRF

Grid Service Reference WS-Addressing Endpoint Reference

Grid Service Handle WS-Addressing Endpoint Reference

HandleResolver portType WS-RenewableReferences

Service data defn & access WS-ResourceProperties

GridService lifetime mgmt WS-ResourceLifeCycle

Notification portTypes WS-Notification

Factory portType Treated as a pattern

ServiceGroup portTypes WS-ServiceGroup

Base fault type WS-BaseFaults

OGSI to WSRF*OGSI to WSRF*


WSRF SpecificationWSRF Specification

WSRF Resource Properties. WSRF Resource Lifetime. WSRF Base Faults. WSRF Service Group.


Web Services and Grids - Web Services and Grids - OGSAOGSA

OGSI problems solved by WSRF

Grid

Web

WSRF

Started far apart in apps & tech

OGSI

GT2

GT1

HTTPWSDL,

WS-*

WSDL 2,

WSDM

Have beenconverging

Jonatan Alava

OGSA requires stateful entities. Web Services are by nature statelessWSDl would be way too complex with OGSIWhat is the Open Grid Service Infrastructure (OGSI)?The Open Grid Services Infrastructure (OGSI) is a set of WSDL specifications defining standard interfaces, behaviors, and schema for grid computing consistent with the OGSA vision. These interfaces and behaviors define the Grid Service. The latest version of the OGSI Specification is available from the OGSI Working Group in the Global Grid Forum. The OGSI specification is being implemented on a number of different platforms including .NET (by this project), Java (GT3 from the Globus Project) and others.


Programming Grid Services Programming Grid Services (GT4)(GT4)

Basic steps involved in creating a grid service– Create the interface using WSDL

Specify the portTypes, messages and data encoding

– Generate Stubs– Add functionality– Compile and Build the code using Globus libraries– Create a GAR (Grid Archive)– Deploy it


OGSA, WSRF & GT4OGSA, WSRF & GT4

B. Sotomayor and L. Childers. Globus Toolkit 4, Programming Java Services. 2006. The Morgan Kaufmann Series in Networking.


OUTLINEOUTLINE




GT4 Java WS CoreGT4 Java WS Core

Java WS Core provides APIs and tools for developing Grid services.

Includes a container based on Apache Axis to host various GT4 services implemented in Java, such as GRAM, RFT, MDS-Index, and our own custom Web Services.

Following WSRF specifications.


GT4 ServicesGT4 Services

What feature/service is most useful to you as you work with GT4 Toolkit?

The globus-build-service.sh and globus-deploy-gar scripts use Ant to create and deploy the GAR file so we don’t need to worry about:

Processing the WSDL file Creating the stub classes from the WSDL Compiling the stub classes Compiling the service implementation Organizing all the files into a very specific directory

structure


Creating a Grid Service (GT4)Creating a Grid Service (GT4)

1. Define the WS interface with WSDL.

2. Implement the service.

3. Define the deployment parameters.

4. Compile everything and generate a GAR file.

5. Deploy the service.


OUR EXAMPLE: MathServiceOUR EXAMPLE: MathService

A simple Math web service. Operations: Addition & Subtraction & Get Value. Resources: Value (integer) & Last operation performed

(String).


MathService: THE 5 STEPS.MathService: THE 5 STEPS.

Step 1: The WSDL.

The Definition

<?xml version="1.0" encoding="UTF-8"?><definitions name="MathService" targetNamespace="http://www.globus.org/namespaces/

examples/MathService_instance“ …>…</definition>

The Definition

<?xml version="1.0" encoding="UTF-8"?><definitions name="MathService" targetNamespace="http://www.globus.org/namespaces/

examples/MathService_instance“ …>…</definition>

The Port Type

<?xml version="1.0" encoding="UTF-8"?><definitions …><portType name="MathPortType" wsrp:ResourceProperties="tns:MathResourceProperties"> <operation name="add"> <input message="tns:AddInputMessage"/> <output message="tns:AddOutputMessage"/> </operation> …</portType></definitions>

The Port Type

<?xml version="1.0" encoding="UTF-8"?><definitions …><portType name="MathPortType" wsrp:ResourceProperties="tns:MathResourceProperties"> <operation name="add"> <input message="tns:AddInputMessage"/> <output message="tns:AddOutputMessage"/> </operation> …</portType></definitions>

The Messages

<?xml version="1.0" encoding="UTF-8"?><definitions …><message name="AddInputMessage"> <part name="parameters" element="tns:add"/></message><message name="AddOutputMessage"> <part name="parameters" element="tns:addResponse"/></message></definitions>

The Messages

<?xml version="1.0" encoding="UTF-8"?><definitions …><message name="AddInputMessage"> <part name="parameters" element="tns:add"/></message><message name="AddOutputMessage"> <part name="parameters" element="tns:addResponse"/></message></definitions>

The Response and Request Types

<?xml version="1.0" encoding="UTF-8"?><definitions …> <xsd:element name="add" type="xsd:int"/> <xsd:element name="addResponse"> <xsd:complexType/> </xsd:element></definitions>

The Response and Request Types

<?xml version="1.0" encoding="UTF-8"?><definitions …> <xsd:element name="add" type="xsd:int"/> <xsd:element name="addResponse"> <xsd:complexType/> </xsd:element></definitions>

The Resource Properties

<portType name="MathPortType" wsrp:ResourceProperties="tns:MathResourceProperties">



</portType>


<portType name="MathPortType" wsrp:ResourceProperties="tns:MathResourceProperties">



</portType>



Step 2: Implementing the Service in Java

The Bare Bones

package org.globus.examples.services.core.first.impl;

import java.rmi.RemoteException;import org.globus.examples.stubs.MathService_instance.*;import org.globus.wsrf.*;import org.globus.wsrf.impl.*;

public class MathService implements Resource, ResourceProperties { …}

The Bare Bones

package org.globus.examples.services.core.first.impl;

import java.rmi.RemoteException;import org.globus.examples.stubs.MathService_instance.*;import org.globus.wsrf.*;import org.globus.wsrf.impl.*;

public class MathService implements Resource, ResourceProperties { …}


/* Resource properties */private int value;private String lastOp;

/* Get/Setters for the RPs */public int getValue() { return value;}

public synchronized void setValue(int value) { this.value = value;}


/* Resource properties */private int value;private String lastOp;

/* Get/Setters for the RPs */public int getValue() { return value;}

public synchronized void setValue(int value) { this.value = value;}



Step 3: Configuring the Deployment (WSDD)

The Service Name<service name=“examples/core/first/MathService” provider=“Handler" use="literal" style="document”>

The WSDL File<wsdlFile>share/schema/examples/MathService_instance/Math_service.wsdl</wsdlFile>

Load on Startup<parameter name="loadOnStartup" value="true"/>

The Common Parameters<parameter name="allowedMethods" value="*"/><parameter name="handlerClass" value="org.globus.axis.providers.RPCProvider"/><parameter name="scope" value="Application"/>

The Service Name<service name=“examples/core/first/MathService” provider=“Handler" use="literal" style="document”>

The WSDL File<wsdlFile>share/schema/examples/MathService_instance/Math_service.wsdl</wsdlFile>

Load on Startup<parameter name="loadOnStartup" value="true"/>

The Common Parameters<parameter name="allowedMethods" value="*"/><parameter name="handlerClass" value="org.globus.axis.providers.RPCProvider"/><parameter name="scope" value="Application"/>



Step 4: Create a GAR file with Ant– Process the WSDL to add missing pieces.– Create stub classes from the WSDL.– Compile stub classes.– Compile service implementation.– Organize all files into its specific directory structure.

./globus-build-service.sh –d <service base directory> -s <service’s WSDL file>

$ ./globus-build-service.sh \ -d org/globus/examples/services/core/first \ -s schema/examples/MathService_instance/Math.wsdl

$ ./globus-build-service.sh \ -d org/globus/examples/services/core/first \ -s schema/examples/MathService_instance/Math.wsdl

$ ./globus-build-service.sh first$ ./globus-build-service.sh first

or



Step 5: Deploy the Service into a Web Service Container– Uses Ant.– Unpacks the GAR.– Copies the WSDL, compiled stubs, compiled implementation &

WSDD into the GT4 directory tree.

$ sudo –u globus globus-deploy-gar \ org_globus_examples_services_core_first.gar

$ sudo –u globus globus-undeploy-gar \ org_globus_examples_services_core_first

$ sudo –u globus globus-deploy-gar \ org_globus_examples_services_core_first.gar

$ sudo –u globus globus-undeploy-gar \ org_globus_examples_services_core_first


MathService: THE CLIENTMathService: THE CLIENT

Tests the service invoking both the add and substract operations.

$ java -cp ./build/stubs/classes/:$CLASSPATH \ org.globus.examples.clients.MathService_instance.Client \ https://la-blade-01.cs.fiu.edu:8443/wsrf/services/core/first/MathService


AxisFault faultCode: {http://schemas.xmlsoap.org/soap/envelope/}Server.userException faultSubcode: faultString: java.io.IOException: No socket factory for 'https' protocol faultActor: faultNode: faultDetail: ...


MAKE THE SERVICE SECURE!MAKE THE SERVICE SECURE!

Create the security-config.xml file.<securityConfig xmlns="http://www.globus.org"> <authz value="none"/></securityConfig>

Modify the deploy-server.wsdd file.<parameter name="securityDescriptor" value="etc/org_globus_examples_services_core_first/security-config.xml"/>

Add the following to the client.static { Util.registerTransport();}…((Stub)mathFactory)._setProperty( Constants.GSI_SEC_CONV, Constants.ENCRYPTION);((Stub)mathFactory)._setProperty( Constants.AUTHORIZATION, NoAuthorization.getInstance());

Our acknowledge to Our acknowledge to Ramakrishna!Ramakrishna!


MAKE THE SERVICE SECURE!MAKE THE SERVICE SECURE!

Is it secure now?Not really… We just added the skeleton to make it secure.


Current value: 15Current value: 10


Current value: 15Current value: 10

Let’s run it again…


GRID SECURITY GRID SECURITY INFRASTRUCTUREINFRASTRUCTURE

Basis for GT4 Security layer. Covers the three pillars of secure communication:

– Privacy.– Integrity.– Authentication.

Family of components (low/high level) to offer security features to programmers.


GRID SECURITY GRID SECURITY INFRASTRUCTUREINFRASTRUCTURE

Level security:

– Transport-level

– Message-level Authentication

– X.509 Digital certificates.

– Username/Password Authorization schemes:

– Server-Side

– Client-Side

– Custom

Credential delegation and single sign-on

– Proxy Certificates Different levels of security:

– Container

– Service

– Resource.


WRITING A SECURE MathServerWRITING A SECURE MathServer

Add security to the MathService example. Now, four operations:

– add– subtract– multiply– divide

We will be able to configure each operation with a different security configuration.


SECURE MathServerSECURE MathServer

1

Modify the security-config-auth.xml

No server-side authorization must be performed.

2 The add method can only be invoked using GSI Secure Conversation.

3 The subtract method can only be invoked using GSI Secure Message.

4 The multiply method can be invoked using GSI Secure Conversation or GSI Secure Message.

5 The divide method can only be invoked using GSI Transport (transport-level security).

6 The rest of the methods can be invoked with any of the authentication methods.

<securityConfig xmlns="http://www.globus.org"> <authz value="none"/> <method name="add"> <auth-method> <GSISecureConversation/> </auth-method> </method> <method name="subtract"> <auth-method> <GSISecureMessage/> </auth-method> </method> <method name="multiply"> <auth-method> <GSISecureConversation/> <GSISecureMessage/> </auth-method> </method> <method name="divide"> <auth-method> <GSITransport/> </auth-method> </method>  <auth-method> <GSISecureConversation/> <GSISecureMessage/> <GSITransport/> </auth-method></securityConfig>

• The service



The Client– Programatically:((Stub)math)._setProperty(Constants.

GSI_SEC_CONV,Constants.ENCRYPTION);– Security descriptor:String secDecFile =

“path/to/security-descriptor.xml”;((Stub)math)._setProperty(Constants.

CLIENT_DESCRIPTOR_FILE, secDescFile);



Client call 1: GSI Transport Client

Client call 2: GSI Secure Conversation Client

[add] ERROR: GSI Secure Conversation authentication required for "{MathService_instance_4op}add" operation.[subtract] ERROR: GSI Secure Message authentication required for

"{MathService_instance_4op}subtract" operation.[multiply] ERROR: GSI Secure Conversation or GSI Secure Message authentication required for "{MathService_instance_4op}multiply" operation.Division was successfulCurrent value: 30

[add] ERROR: GSI Secure Conversation authentication required for "{MathService_instance_4op}add" operation.[subtract] ERROR: GSI Secure Message authentication required for

"{MathService_instance_4op}subtract" operation.[multiply] ERROR: GSI Secure Conversation or GSI Secure Message authentication required for "{MathService_instance_4op}multiply" operation.Division was successfulCurrent value: 30

Addition was successful[subtract] ERROR: GSI Secure Message authentication required for "{http://www.globus.org/namespaces/examples/ MathService_instance_4op}subtract" operation.Multiplication was successfulDivision was successfulCurrent value: 180

Addition was successful[subtract] ERROR: GSI Secure Message authentication required for "{http://www.globus.org/namespaces/examples/ MathService_instance_4op}subtract" operation.Multiplication was successfulDivision was successfulCurrent value: 180


GT4 IDE software toolsGT4 IDE software tools

Are there any current GT4 IDE software tools?

– Globus Service Build Tools http://gsbt.sourceforge.net/ GT4IDE: Eclipse 3 plug-in that will allow GT4 programmers to develop

WSRF Java Web Services easily. globus-build-service: The same Ant buildfile + script included in the

tutorial.


USEFUL LINKSUSEFUL LINKS

http://www.cs.fiu.edu/~sadjadi/Teaching/gt4website/

Globus toolkit 4 Programmer’s Tutorialhttp://gdp.globus.org/gt4-tutorial/

Globus toolkit 4: Programming Java Serviceshttp://www.gt4book.com/

OASIS.http://www.oasis-open.org/

The Globus Alliance;http://www.globus.org/

Documents

9th Lecture COP 4991 Component-Based Software Development Instructor: Masoud Sadjadi sadjadi/Teaching/ Developing Grid Services