Peer-to-Peer Grids P2P and Grid Communities Working Together. Topics Covered. Knowledge Review. October 18, 2004

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1 Peer-to-Peer Grids and Grid Communities Working Together ctober 18, 2004 Topics Covered 2 Enable ad hoc communities of low-end clients to advertise and access files on communal communities nvolve services to set-up and join peer groups Browse and access files on a peer Advertise one s interest in a particular file Grid Exemplified by infrastructure client-server model Allows seamless access to supercomputers and datasets Support job submittal and status services Access to sophisticated data management systems Structured robust security services 3 1

2 What happens if we combine the capabilities of technology and Grids? Peer- to- Peer Grid 4 Peer-to-Peer Grid Web services linked by event services Uniform XML interfaces Application level routing 5 Benefits of s unction over HTTP to expose and access Web services with technologies they already have in place Core standards are widely accepted to enable Web services: SAP, WSDL, and UDD mprove collaborative software development Modular programs can be built Less prone to errors Enable programmers to reuse components 6 2

3 Compared to ther Computing Models Programmable Encapsulates a task When an application passes data or instructions to it, the service processes that information, and if required, returns information back to the application Based on XML As an open, text-based standard, XML enables Web services to communicate with other applications even if written in other languages and running on other operating systems Self-describing Accompanied by information explaining what they do Contain information on how other applications can access and use them (written in WSDL) Discoverable Ability of applications and developers to search for and locate desired Web services through registries 7 XML (Extensible Markup Language) Developed from SGML (Standard Generalized Markup Language) Accepted standard for describing data and creating markup languages Separation of content from its presentation XML Parsers are software programs that check an XML document s syntax and makes the data available to applications f the syntax is correct, the document conforms to the XML specification and is considered well-formed XML document can reference another document (DTD) that defines the XML document s structure 8 Peer-to-Peer Grid External resources linked by a collection of Web services linked by messages whose communication forms a distributed system integrating the component parts Distributed bject technology is implemented with objects defined in a WSDL CBA and JAVA (coupled with XML wrapper) to provide uniform interface 9 3

4 Description Language XML-based language that provides documents which contain descriptions of the Web service Describes service s capabilities, location on the Web and instructions on how to access it Defines the structure of the messages that a Web service sends and receives Using this information, applications searching for a Web service to fill a specific need can analyze the WSDL files of several comparable services and choose between them WSDL Parts Wrapped in the <definitions> XML element <types> section defines all data types used by the service <message> section defines input and output parameters of the Web service, referring back to the data types defined in the <types> section of the preceding code.net defines three access methods HTTP GET, HTTP PST, and SAP f a method uses the request-response message pattern, you will see two <message> sections for each of the three access methods: one declaring the input parameter and one declaring the output parameter 11 WSDL Parts <porttype> section ties the access methods to the messages declared in the <message> section Since there are three access methods, there will be three corresponding <porttype> sections <bindings> section declares the protocols used to access the echo Web method HTTP GET, HTTP PST, and SAP Defines the encoding used to send data over the wire Use UL encoding for HTTP GET and HTTP PST but use encoding mechanism provided by the SAP standard for SAP <service> section ties everything together See your web service appear with its methods that has all the bindings attached to it 12 4

5 Service Model Accepts one or more inputs and gives one or more results Everything is a resource A service corresponds roughly to a computer program or process Ports reference subroutine calls with input parameters and returned data Services can be dynamically migrated between computers 13 Grids Web services Security Access to computers Access to various forms of databases Messaging sub-system between web services and external resources addressing functionality, performance, and fault-tolerance 14 ther Capabilities Toolkits to enable applications to be packaged as Web services Application meta-data to describe all stages of a scientific endeavor Network monitoring and collaboration Portal technology which accepts user control and delivers user interfaces 15 5

6 GD P 2 P Database Database nterfaces Event/Message Brokers ntegrate and GD/WS Event/Message Brokers nterfaces Database 16 How Does This Work? Peer- to- peer grid with peer groups Managed locally Arranged into a global system Supported by core servers Example JXTA search technology (middle- tier database systems) Uses either or more robust Grid security 17 Communication Subsystem Evaluate the thin client and server based application model Analyze slow networks, high frequency of dropped packets, firewalls stopping application channels issues in telecom industry that are problematic to rapid deployment of optical and wireless networks 18 6

7 Peer-to-Peer Grid Event Service Messaging subsystems that manage communication between external resources, web services and clients Highest possible system performance and reliability All communication will be handled by a single messaging or event subsystem Specialized protocols for high volume data transfer lexible robust approaches for control channels 19 System Components/Event Service S E V E S aw esources outers/brokers C L E N T S Services 20 Distributed Brokers/Event Service Community Community Broker esource Broker Broker Broker Community Broker Database Software Multicast Broker Community 21 7

8 Communication Model outing Destination Source Matching User Profiles & Customization ilter Workflow 1 Virtual Queue 2 WSDL Ports Abstract Application nterface Message or Event Broker Message System nterface WSDL Ports Abstract Application nterface 22 Audio- Video Conferencing Publish/subscribe mechanism to advertise the availability of video feed Client interested in receiving video would negotiate transmission details Video can be sent directly from publisher to subscriber or publisher to web service and then web service to subscriber 23 in Grids Grids support virtual enterprises or organizations involves sharing of Web services, objects or resources Similar to the sharing of legacy systems 24 8

9 Asynchronous Asynchronous collaboration Different members of a community access the same resource No special time constraint and each member can access resource in own manner ault- tolerant because each member can manage and accommodate difficulties such as poor network connectivity 25 Synchronous Sharing of information is done in real- time mplies delays of around msec per participant Timings can be compared to the loading of a new page ault- sensitive f workstation crashes in synchronous collaboration, after recovering from the error, one cannot resume where one lost contact because the rest of the collaborators have moved on 26 Sharing Mechanisms oughly the same for both asynchronous and synchronous cases ndirect most powerful and is familiar in with JXTA (XML-expressed advertisements to link together those interested in a particular topic) 27 9

10 Grid Examples Audio video conferencing systems Direct method with to alert of an upcoming session Commercial web-conferencing systems like WebEx and Placeware Notifications for object availability and update Version Control systems nly major events are tracked (check-in(out)) 28 Every Web service has one or more ports in each of three classes below. WSDL Application or Content Source U esource acing Ports defining User acing nput (Control) and utput Ports 29 Synchronous Modes MASTE bject or WS bject or WS bject or WS bject or WS Viewer bject or WS Display SHAED DSPLAY Event (Message) Service WS Display ther Participants WS Display 30 10

11 Shared s nput Ports Event (Message) Service U U WS Viewer WS Display MASTE WS Viewer WS Display ther Participants U WS Viewer WS Display 31 Collaborative Services User-acing Ports U Message nterceptor WS Viewer MASTE WS Display WS Viewer WS Display Event (Message) Service ther Participants WS Viewer WS Display 32 n Conclusion is a web service Ports allowing sessions to be defined nteract with event service Sharing using an input or user-facing port of a Web service allows one to build flexible environments needed to support Grid communities built on this infrastructure 33 11

12 Cellular Grids Audio Video Conferencing using NaradaBrokering Load Balancing with Structured Grids 34 Are there any problems with guaranteeing universal access with the Grids? Are Grids are a nice collaborative effort for sharing data among different sources? What mechanisms can be put in place for better results? s structured Grid the answer? 35 eferences Peer-to-Peer Grids, Authors: Geoffrey ox, Dennis Gannong, Sung-Hoon Ko, Sangmi Lee, Shrideep Pallickara, Marlon Pierce, Xiaohong Qiu, Xi ao, Wenjun Wu, Minjun Wang, Ahmet Uyar (Community Grid Computing Laboratory, ndiana University) Demonstrations of Collaborative s and Peer-to-Peer Grids Authors: Minjun Wang, Geoffrey ox, and Shrideep Pallickara (Community Grid Computing Laboratory, ndiana University) A Scaleable Event nfrastructure for Peer-to-Peer Grids, Authors: Geoffrey ox, Shirdeep Pallicakara, Xi ao (ndiana University)- Proceedings of the 2002 joint ACM-SCPE conference on Java Grande, Seattle, Washington 2002 Achieving Load Balancing in Structured Peer-to-Peer Grids, Authors: Cales Pairot, Pedro Garcia, Antonio Skarmeta, and uben Mondejar, Universitat ovira i Virgili (Spain), CCS 2004: 4 th nternational Conference, Krakow Poland June 6-9, 2004 ntegration of Narada Brokering and Audio/Video Conferencing as a, Authors: Hasan Bulut, Geoffrey ox, Shrideep Pallickara, Ahmet Uyara, and Wenjun Wu, (Community Grid Computing Laboratory, ndiana University) Message-Based Cellular Peer-to-Peer Grids: oundations for Secure ederation and Autonomic Services, Authors: Geoffrey ox, Sang Lim, Shrideep Pallickara, Marlon Pierce, (Community Grid Computing Laboratory, ndiana University) 36 12