Advancement Of Structured Information Standards - Case Study Example

The Evolution of Grid Solutions from Resource-Oriented To Service-Oriented Architectures Introduction Grid computing is an emerging computing model that utilizes the processing powers of distributes parallel processing infrastructure across a wide area network for the complex and high volume of processing requirements. According to IBM Grid Computing is "the ability, using a set of open standards and protocols, to gain access to applications and data, processing power, storage capacity and a vast array of other computing resources over the Internet. A Grid is a type of parallel and distributed system that enables the sharing, selection, and aggregation of resources distributed across 'multiple' administrative domains based on their (resources) availability, capacity, performance, cost and users' quality-of-service requirements" The ideas of the grid computing were first conceived by Ian Foster, Carl Kesselman and Steve Tuecke. Grid computing increases the throughput of a networked system. Various heterogeneous but networked resources across administrative boundaries can be modeled in to virtual computer architecture for resource sharing. The concept of grid computing is to solve complex computational problems that can not be solved by the limited resources of a single computer or group of computers within an organization. Huge unused resources such as CPU and/or disk storage space of a large number of geographically separate computers can be modeled in to a grid for performing complex computational problems. Grid computing is can be comfortably used for solving protein folding, financial modeling, earthquake simulation, and climate/weather modeling problems. To summarize there are two main functions of a computing grid, first optimally utilizing available computing resources and second, to provide a distributed multi-user environment. Grid Computing Resource Oriented Architecture Fig : A comparison of growth in networking technolies and processing power It is apparent from the above figure that networking technologies are more rapidly than the microprocessor technology. There is always a large chunk of processing power that remains underutilized in many computer clusters. Advancement in networking technology can logically be used to club all these underutilized resource thus solving the crunch of processing power in some computing clusters and considerably reducing the processing cost. During the early evolution of grid computing, it was solely aimed to efficiently utilize the underutilized resources. Evolution of Grid Computing in to a Service Oriented Architecture Software complexity has been rapidly increasing in last four decades and it has reached to such a level that it became difficult to deal with. With this, need of swiftness in response to business requirement is also increasing. IT industry has been through various computing architectures of distributed processing for better resource utilization. This led to the evolution of various programming languages running on different platforms and a number of networking products. However, full resource integration is still very complex due to multiple development platforms. Service Oriented Architecture (SOA) is now considered as next big leap in computational architecture which may help IT industry to meet complex future needs. The concept of SOA has been in development since a long time. Ever since its inception it has been bogged down due to various problems of integrating different available object models and development of a robust architecture for simple, fast and secure integration of various development platforms. Defining SOA An SOA application is a composition of various distributed services performing some well defined tasks. A service-oriented architecture (SOA) is a specific type of distributed system in which the agents are "software services" that perform some well-defined operation (i.e., it provides a service), and this type of architecture can be invoked outside of the context of a larger application. IBM also defines SOA as "a loosely coupled architecture with a set of abstractions relating to components granular enough for consumption by clients and accessible over the network with well-defined policies as dictated by the components". Services acts as user-interface of larger software application. This separation of functionality helps the users of the larger application to be concerned only with the interface description of the service. These services may belong to different platforms. A "service" is the atomic unit of SOA architecture. Fig: General architecture of a SOA (a simple interaction cycle) Above illustration of a simple service interaction cycle shows the relationship between Service Provider, Service Consumer and Service Registry in SOA architecture. Services are a group of business processes and generally have the following characteristics: Services are independent of each other and may be individually useful. These can be integrated to provide a higher-level service which enables the reuse of services and enhance their capabilities. Services can be defined by the way they communicate with other services and exchange messages. Services are generally resources centric hence are useful if particular resource is available over grid for example a service may be used to query a database. Services present their capabilities, interfaces, policies, and supported communications protocols through a Registry Service but the execution details such as programming language and platform are of no concern to clients, and are not revealed. Service Providers need to register themselves with Service Registry in order to offer their services to Service Consumers connected with the grid. Services are integrated using functions such as Find, Bind and Execute. In Service Oriented Grids service interaction cycle starts with a service advertising its capabilities trough a Service Registry. Service Consumer, which may or may not be a service itself, requests Service Registry for a required specific service and in response Service Registry returns a list of services available that may fit the request. Service Consumer, selects a service, if found helpful, and passes a request message to that service using a mutually understandable protocol and if authorized, can use the service. There may be the cases when Service Registry returns a null list if there is no suitable service as per the request of Service Consumer. The development in grid computing is dependant on the development of grid middleware such as software components and protocols. These middleware components and protocols are used to provide required controlled access to resources. In its development stage, grids are generally built up of ad hoc public components and proprietary technologies. These proprietary technologies have had their advantages and disadvantages and were the limiting factors in the growth of futuristic service oriented architecture as a Service Oriented Architecture need to be highly scalable and interoperable to cater various architectural platforms and technologies. During the development stage of grid computing, a number of custom middleware solutions were created to solve the grid problems for resource sharing which resulted in non-interoperable solutions and problematic integration among the grid members due the use of various developing languages, platforms and standards. Evolution of grid computing into a Service Oriented Architecture focuses on the easier integration, security, and QoS aspects of resource sharing. Development of web technology and web services has made implementation of true service oriented architecture possible. Technologies required for deploying service oriented architecture are available. Fig: Architecture of a service oriented grid (Source: reference 1) Service oriented architectures transcend web services as web services are collection of technologies such as XML, SOAP, WSDL and UDDI which are used for developing programming solutions for specific application integration problem where as a true service oriented architecture is more than a particular set of technologies. It incorporates various technologies, platforms and services running independently of each other. Two basic characteristics of service oriented architecture are independence of services running in grid and manageability of services. A true service oriented architecture offers following benefits for efficient management and utilization of resources: Security of services and resources: SOA requires authorization of the request, encryption and decryption as required, validation, etc. which prevents unauthorized use of resources. Easy Deployment: SOA allows easy deployment and redeployment or moving of services around the network for performance, redundancy for availability of the resources. Event Logging: all events in a SOA are logged for auditing, metering, etc. Dynamic rerouting: it helps in fail over and load balancing in grids. Maintenance: SOA services are developed over ease of management of resources. It also helps in management of new versions of the service. Loose Coupling in SOA Loose coupling is the main characteristic of service oriented architecture that differentiates it from web services and other distributed services. The term loose coupling means the software applications and components running in a grid are not dependent on each other. One software component is little aware of other component. Interaction of one component with other component is need specific, which means a software component will interact with other only when there is a specific need of that component for particular information. A service consumer can access required service, its functions and interfaces using mutually acceptable protocols. This help in avoiding contradictions in various services running in grid. Loose coupling in general offer following benefits: Flexibility: A service can be located on any server, and relocated as necessary. As long as it maintains its registry entry, prospective clients will be able to find it. Scalability: Services can be added and removed as demand varies. Replaceability: Provided that the original interfaces are preserved, a new or updated implementation of a service can be introduced, and outdated implementations can be retired, without disruption to users. Fault tolerance: If a server, a software component, or a network segment fails, or the service becomes unavailable for any other reason, clients can query the registry for alternate services that offer the required functionality, and continue to operate without interruption. Comparison of resource oriented and Service-oriented grid architectures There have a long debate for the differences and usability of resource oriented and service oriented grid architectures. The only purpose of resource oriented grid architecture has been the utilization of underutilized network resources. There was no emphasis on how these resources are interacting with each other and manageability of grid. In a resource oriented grid, generally, an object, service or software application is fully aware of other resources available over the grid. One client has the knowledge of all other objects and could communicate with them through synchronous invocation of remote methods with the help of special-purpose protocols. In contrast to resource oriented architecture, services, applications or objects in service oriented architecture are loosely coupled with each other. A service in the grid needs not to be aware of all services running over grid. It needs to communicate with only those services which it needs and authorized to access. In service oriented architecture, services communicate with the help of message exchanges which could be one-way and may be synchronous or asynchronous. It is not necessary that request of service and response come from the same set of services which means response of a request may come from a service which was not requested. Service oriented grid architecture enables the grid resources to use standard interfaces defined as part of their service extensions to present their functions and capabilities in front of other grid users or client services. Operational functions of various layers of service oriented grid are fully independent which enables an efficient and easy integration between different services. Conclusion From above discussion, it is clear that service oriented grid may be used as a basis of next generation of distributed application and resource management technologies. The document shows basic components of a grid environment and relationship between various components and services of service oriented grid architecture. Service Oriented architecture is interoperable with various present day technologies and can be efficiently scaled and managed. The benefits of service-oriented architectures are getting more visible across various industries. Service orientation can serve as a seamless interaction mechanism between business and IT, leading to a continuous alignment of the business needs and technological solutions for the enterprise. On the other hand, though the service oriented architecture is considered as next big leap in IT sector, there are number of issues that need to overcome such as still developing technologies, various developing standards and the significant performance overhead and complexities service accessibility. References: 1. Latha Srinivasan and Jem Treadwell, An Overview of Service-oriented Architecture, Web Services and Grid Computing, HP Software Global Business Unit, November 3, 2005 2. IBM Grid computing, http://www-03.ibm.com/grid/ 3. Open Grid Services Architecture (OGSA) v1.0: http://www.gridforum.org/documents/GFD.30.pdf 4. Defining the Grid: A Roadmap for OGSA Standards v1.0: http://www.gridforum.org/documents/GFD.53.pdf 5. OGSA Glossary of Terms v1.0: http://www.gridforum.org/documents/GFD.44.pdf 6. World Wide Web Consortium (W3C): http://www.w3.org 7. Organization for the Advancement of Structured Information Standards (OASIS): http://www.oasis-open.org 8. Distributed Management Task Force (DMTF): http://www.dmtf.org 9. Global Grid Forum: http://www.ggf.org 10. Chatterjee & Webber: Developing Enterprise Web Services - An Architect's Guide (Prentice Hall) Read More