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Session18  Madduri

Session18 Madduri






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    Session18  Madduri Session18 Madduri Presentation Transcript

    • Service Oriented Architecture and Globus Toolkit Ravi K Madduri Argonne National Laboratory University of Chicago
    • Agenda q Principles of Service Oriented Architecture q The Globus Toolkit q Web Services Basics q Grid Services q What people punt on ? x Intro to Globus Security, Service Registries q Workflows we created q Lessons learned
    • Principles of Service Oriented Architecture q Guiding principles define the ground rules for development, maintenance, and usage of the SOA x Reuse, granularity, modularity, composability, componentization and interoperability x Standards compliance (both common and industry-specific) x Services identification and categorization, provisioning and delivery, and monitoring and tracking
    • Architectural Principles q Service encapsulation – Many web services are consolidated to be used under the SOA. q Service loose coupling – Services maintain a relationship that minimizes dependencies and only requires that they maintain an awareness of each other q Service contract – Services adhere to a communications agreement, as defined collectively by one or more service description documents q Service abstraction – Beyond what is described in the service contract, services hide logic from the outside world
    • Architectural Principles q Service reusability – Logic is divided into services with the intention of promoting reuse q Service composability – Collections of services can be coordinated and assembled to form composite services q Service autonomy – Services have control over the logic they encapsulate
    • Architectural Principles q Service optimization – All else equal, high- quality services are generally considered preferable to low-quality ones q Service Discoverability - Services are designed to be outwardly descriptive so that they can be found and assessed via available discovery mechanisms q Service Relevance – Functionality is presented at a granularity recognized by the user as a meaningful service
    • Globus Software: dev.globus.org Globus Projects OGSA-DAI GT4 MPICH- G2 Java Data Replica Delegation MyProxy Runtime Rep Location GridWay C GSI- CAS GridFTP MDS4 Runtime OpenSSH Incubator Reliable Mgmt Python C Sec GRAM File GT4 Docs Runtime Transfer Common Execution Info Security Data Mgmt Other Runtime Mgmt Services
    • Web Service Basics q Web Services are basic distributed computing technology that let us construct client-server interactions Borja Sotomayor , http://gdp.globus.org/gt4-tutorial/multiplehtml/ch01s02.html
    • Web Service Basics 2 q Web services are platform independent and language independent x Client and server program can be written in diff langs, run in diff envt’s and still interact q Web services describe themselves x Once located you can ask it how to use it q Web services are ideal for loosely coupled systems x Unlike CORBA, EJB, etc.
    • WSDL: Web Services Description Language Define expected messages for a service, and their (input or output parameters) An interface groups together a number of messages (operations) Bind an Interface via a definition to a specific transport (e.g. The network location where the service is HTTP) and messaging (e.g. implemented , e.g. http://localhost:8080 SOAP) protocol
    • Real Web Service Invocation Discover Describe Invoke Borja Sotomayor , http://gdp.globus.org/gt4-tutorial/multiplehtml/ch01s02.html
    • Web Services Server Applications q Web service – software that exposes a set of operations q SOAP Engine – handle SOAP requests and responses (Apache Axis) q Application Server – provides Container “living space” for applications that must be accessed by different clients (Tomcat) q HTTP server- also called a Web server, handles http messages Borja Sotomayor , http://gdp.globus.org/gt4-tutorial/multiplehtml/ch01s02.html
    • Let’s talk about state q Plain Web services are stateless Borja Sotomayor , http://gdp.globus.org/gt4-tutorial/multiplehtml/ch01s03.html
    • However, Many Grid Applications Require State Borja Sotomayor , http://gdp.globus.org/gt4-tutorial/multiplehtml/ch01s03.html
    • Keep the Web Service and the State Separate q Instead of putting state in a Web service, we keep it in a resource q Each resource has a unique key Borja Sotomayor , http://gdp.globus.org/gt4-tutorial/multiplehtml/ch01s03.html
    • Resources Can Be Anything Stored Web Service + Resource = WS-Resource Address of a WS- resource is called an end-point reference
    • Web Services So Far q Basic client-server interactions q Stateless, but with associated resources q Self describing using WSDL q But we’d really like is a common way to x Name and do bindings x Start and end services x Query, subscription, and notification x Share error messages
    • Standard Interfaces q Service information q State representation x Resource GetRP x Resource Property GetMultRPs q State identification SetRP x Endpoint Reference Client Web QueryRPs Service q State Interfaces Subscribe x GetRP, QueryRPs, GetMultipleRPs, SetRP SetTerm Time q Lifetime Interfaces Destroy x SetTerminationTime x ImmediateDestruction q Notification Interfaces x Subscribe x Notify q ServiceGroups
    • WSRF & WS-Notification q Naming and bindings (basis for virtualization) x Every resource can be uniquely referenced, and has one or more associated services for interacting with it q Lifecycle (basis for fault resilient state management) x Resources created by services following factory pattern x Resources destroyed immediately or scheduled q Information model (basis for monitoring & discovery) x Resource properties associated with resources x Operations for querying and setting this info x Asynchronous notification of changes to properties q Service Groups (basis for registries & collective svcs) x Group membership rules & membership management q Base Fault type
    • WSRF vs XML/SOAP q The definition of WSRF means that the Grid and Web services communities can move forward on a common base q Why Not Just Use XML/SOAP? x WSRF and WS-N are just XML and SOAP x WSRF and WS-N are just Web services q Benefits of following the specs: x These patterns represent best practices that have been learned in many Grid applications x There is a community behind them x Why reinvent the wheel? x Standards facilitate interoperability
    • WS Core Enables Frameworks: E.g., Resource Management Applications of the framework (Compute, network, storage provisioning, job reservation & submission, data management, application service QoS, …) WS-Agreement WS Distributed Management (Agreement negotiation) (Lifecycle, monitoring, …) WS-Resource Framework & WS-Notification (*) (Resource identity, lifetime, inspection, subscription, …) Web services (WSDL, SOAP, WS-Security, WS-ReliableMessaging, …) * An evolution of Open Grid Services Infrastructure (OGSI)
    • Globus and Web Services User Applications Globus (e.g., Apache Axis) Globus Container and Admin WSRF Web Registry Services WS-A, WSRF, WS-Notification WSDL, SOAP, WS-Security Globus Core: Java , C (fast, small footprint), Python
    • Globus and Web Services User Applications Custom Globus (e.g., Apache Axis) Globus Container and Admin WSRF Web Registry Custom WSRF Web Services Services Services WS-A, WSRF, WS-Notification WSDL, SOAP, WS-Security Globus Core: Java , C (fast, small footprint), Python
    • Globus Security q Extensible authorization framework based on Web services standards x SAML-based authorization callout q Security Assertion Markup Language, OASIS standard q Used for Web Browers authentication often q Very short-lived bearer credentials x Integrated policy decision engine q XACML (eXtensible Access Control Markup Language) policy language, per-operation policies, pluggable
    • Delegation Service q Higher level Hosting Environment service Service1 q Authentication Service2 Resources protocol EPR Delegation Service independent Service3 Delegate Refresh q Refresh interface Refresh q Delegate once, EPR Delegate share across services and Client invocation Rachana Ananthakrishnan
    • Delegation q Secure Conversation x Can delegate as part of protocol x Extra round trip with delegation x Types: Full or Limited delegation x Delegation Service is preferred way of delegating q Secure Message and Secure Transport x Cannot delegate as part of protocol Rachana Ananthakrishnan
    • Globus’s Use of Security Standards Supported, Supported, Fastest, but slow but insecure so default
    • Monitoring and Discovery System (MDS4) q Grid-level monitoring system x Aid user/agent to identify host(s) on which to run an application x Warn on errors q Uses standard interfaces to provide publishing of data, discovery, and data access, including subscription/notification x WS-ResourceProperties, WS-BaseNotification, WS-ServiceGroup q Functions as an hourglass to provide a common interface to lower-level monitoring tools
    • Taverna A sample caGrid workflow caGrid Scavenger with semantic/ metadata based caGrid service query
    • Sample Workflow with caDSR q Scientific value Workflow input x To find all the UML packages related to a given context (‘caCore’). caGrid services x Not a real scientific experiment. q Simple. “Shim” q Important in caGrid. services q Steps x Querying Project object. x Do data transformation. x Querying Packages object Workflow output and get the result.
    • Protein sequence information query q Scientific value x To query protein sequence information out of 3 caGrid data services: caBIO, CPAS and GridPIR. x To analyze a protein sequence from different data sources. q Steps x Querying CPAS and get the id, name, value of the sequence. x Querying caBIO and GridPIR using the id or name obtained from CPAS.
    • Microarray clustering* q Scientific value x A common routine to group genes or experiments into clusters with similar profiles. x To identify functional groups of genes. q Steps x Querying and retrieving the microarray data of interest from a caArrayScrub data service at Columbia University x Preprocessing, or normalize the microarray data using the GenePattern analytical service Workflow in/output at the Broad Institute at MIT caGrid services x Running hierarchical clustering using the geWorkbench others “Shim” services analytical service at Columbia University *Wei Tan, Ravi Madduri, Kiran Keshav, Baris E. Suzek, Scott Oster, Ian Foster. Orchestrating caGrid Services in Taverna. ICWS 08.
    • Execution Execution result as trace xml 1936 gene expressions
    • Lymphoma prediction type prediction q Scientific value * x Using gene-expression patterns associated with DLBCL and FL to predict the lymphoma type of an unknown sample. x Using SVM (Support Vector Machine) to classify data, and predicting the tumor types of unknown examples. q (Major) steps x Querying training data from experiments stored in caArray. x Preprocessing, or normalize the microarray data. x Adding training and testing data into SVM service to get classification result. *Fig. from MA Shipp. Diffuse large B-cell lymphoma outcome prediction by gene-expression profiling and supervised machine learning. Nature medicine,
    • Querying Preprocessing Classifying & predicting
    • Lymphoma type prediction q Result snippet *Classification errors are highlighted. Acknowledgement: Juli Klemm, Xiaopeng Bian, Rashmi Srinivasa (NCI) Jared Nedzel (MIT)
    • Lessons Learned q Service abstraction not applicable to everything q Virtual Organization concepts still good q Web services is one way to create service oriented architectures but not always the best way q Make implementation agnostic of tools underneath q True value in ability to create workflows
    • Service-Oriented Science q People create services (data or functions) … q which I discover (& decide whether to use) … q & compose to create a new function ... q & then publish as a new service. q  I find “someone else” to host services, so I don’t have to become an expert in operating services & computers! !! q  I hope that this “someone else” can manage security, reliability, scalability, … “Service-Oriented Science”, Science, 2005
    • Questions ?