service oriented architecture history

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Elizabeth Millard (January 2005). The cloud user just uses a URL to access the cloud storage, and the vendor can perform any needed optimizations at the backend to ensure that the access is efficient and satisfies the quality of service that has been agreed upon. The service can be used and reused throughout an organization rather than built within each individual application that needs the functionality offered by the service. In all of the previous use cases, there are a set of service APIs specified. A service-oriented architecture (SOA) is an architectural pattern in computer software design in which application components provide services to other components via a communications protocol, typically over a network. However, there are several challenges to achieve a fully automated solution. Also services can be "mega-corporations" constructed as the coordinated work of subordinate services. Service-oriented architecture is a design principle in which software is designed and built in pieces that provide well-defined services when requested. Service Oriented Architecture.pdf - Service Oriented... School Strathmore University; Course Title IT 4105; Uploaded By JusticeVulture665. Avoid costly business errors and focus on improving business processes—not integrating systems. The term REST is used in two distinct but related ways: to denote the protocol infrastructure used for the World Wide Web, namely the Hypertext Transfer Protocol (HTTP); and to denote a software architectural pattern that can be implemented by web protocols. There are two major roles within SOA: the service provider and the service consumer. Applications running on either platform can also consume services running on the other as web services that facilitate reuse. SOMF also provides a common modeling notation to address alignment between business and IT organizations. The key is independent services with defined interfaces that can be called to perform their tasks in a standard way, without a service having foreknowledge of the calling application, and without the application having or needing knowledge of how the service actually performs its tasks. Service providers are components that provide a service that can be used by any number of clients. Service Oriented Infrastructure or SOI provides a system for describing information technology (IT) infrastructure as a service. [36], Another major problem faced by SOA is the lack of a uniform testing framework. Monolithic applications can be successful, but increasingly people are feeling frustrations with them – especially as more applications are being deployed to the cloud. Popular cloud service providers such as Amazon Elastic Compute Cloud (EC2) use Web Services to provide compute and storage infrastructure services (Gruschka and Iacono, 2009). If a given service is not using all the resources on an Amazon EC2 instance, additional services can be launched in containers on that instance that make use of the idle resources. This encourages good design insofar as the service is designed without knowing who its consumers are. A TP application may exist as a combination of reusable services. Some of the top-level processes have multiple outputs. That maximizes not only the alignment with business needs, but also the return on IT investments. We use it here in the former sense, which we call REST/HTTP. The combination of factors among others took the SOA movement out of the mainstream. Because services will be spread across multiple hosts, it can be difficult to keep track of which hosts are running certain services. To push out a new version of a service running on a given host, the running container can simply be stopped and a new container started that is based on a Docker image using the latest version of the service code. This differs dramatically from ESB, which contains substantial logic for message routing, schema validation, message translation, and business rules. The user creates a container, puts the relevant data objects in it and specifies the data services needed for the container. SOA aligns information systems technology well with business objectives by modeling an application as a composition of reusable services. These services inter-operate based on a formal definition (or contract, e.g., WSDL) that is independent of the underlying platform and programming language. Designed as components, services can be reused more effectively, thus reducing development time and the associated costs. While microservices and SOA are different on many levels – architectural style, implementation examples, associated technologies – they have played strikingly similar roles in the technology landscape. To start a transaction T, the server creates a resource RT that represents the transaction. This metadata describes both the functional characteristics of the service and quality-of-service characteristics. Standard HTTP verbs (PUTs and GETs) are used in the API and all other semantics of the data are passed in the body of the message payload. But there are some disadvantages to microservices as well. The REST/HTTP approach is also simpler than the RPC style of interaction more commonly used with Web Services, and thus is easier to use. A TP system that is created in whole or in part using the SOA approach may include multiple reusable services offered by a single transaction program or by multiple distributed services. Scaling requires scaling of the entire application rather than parts of it that require greater resource. Service-oriented architecture aims to allow users to combine large chunks of functionality to form applications which are built purely from existing services and combining them in an ad hoc manner. This indicates that the input parameters will need to specify the XML tags (in this case) to include in the output. Unlike Web Services, transaction propagation for REST/HTTP isn't defined. CDMI cloud storage reference model. [29], SOA has been conflated with Web services;[30] however, Web services are only one option to implement the patterns that comprise the SOA style. The term service has been used for more than two decades. Figure 10.5 describes the role of OCCI with the provider's environment. All this information can be obtained programmatically and not only through a user interface. We’ll talk a lot more about TP software architecture in Chapter 3. SOA-based computing packages functionalities into a set of interoperable services, which can be integrated into different software systems belonging to separate business domains. A service is a well-defined and self-contained functionality. A service is completely defined by service contracts and description documents. Philip A. Bernstein, Eric Newcomer, in Principles of Transaction Processing (Second Edition), 2009. A new RFC to define special mime types to be used by CDMI has been defined. [35], A primary challenge faced by service-oriented architecture is managing of metadata. [31][32][33], Stateful services require both the consumer and the provider to share the same consumer-specific context, which is either included in or referenced by messages exchanged between the provider and the consumer. SOA-based systems can therefore function independently of development technologies and platforms (such as Java, .NET, etc.). The service can be tested as a 'black box' using existing stubs corresponding to the services it calls. It contains the information such as trolley ID, maximum volume of trolley, current location, and current operator of trolley. Thus SOA governance comes into the scheme of things. CDMI use cases: The CDMI standard addresses a number of use cases of cloud storage, namely, (a) catering to elastic on-demand access to storage – increasing or decreasing storage provisioning to be able to handle the load on a specific data object; (b) outsourcing regular backup of data; (c) retaining data for a certain number of years for audit compliance and other legislative needs; (d) storage for cloud-computing applications, which is the use case that has been extensively described in this book. Figure 1.3. Lower level enterprise integration patterns that are not bound to a particular architectural style continue to be relevant and eligible in SOA design. They include a service provider that offers a service, a requester that invokes a service, and a registry (sometimes called a repository) that publishes service descriptions. A multistep REST/HTTP-based exchange between two companies can use a compensation-based transaction protocol. Service Oriented Architecture (SOA) is a style of design in which applications are composed in whole or in part of reusable services. Over time it is often hard to keep a good modular structure, making it harder to keep changes that ought to only affect one module within that module. An image processing service can be implemented using a high-performance language like C++. … The concept of services introduced by service-oriented architecture has become what is now a central component of modern cloud computing and virtualization in things like middleware and microservices. These services use technology agnostic protocols,[41] which aid in encapsulating choice of language and frameworks, making their choice a concern internal to the service. From Wikipedia, the free encyclopedia Service-oriented architecture (SOA) is a style of software design where services are provided to the other components by application components, through a communication protocol over a network. Each use case is supported by some CDMI APIs. This architecture and the accompanying use cases documents describe standardized interfaces and data formats that can be used to manage cloud environments, mainly IaaS platforms. The standard prescribes special metadata called data-system metadata that is used to tag data. Figure 10.4 shows the decomposition of services based on the matrix.4 The processes have been labeled. Many vendors now support Web Services protocols. Service-orientation is a way of thinking in terms of services and service … IBM Vice President of Web Services Michael Liebow says that SOA "builds highways".[27]. SOA facilitates the development of enterprise applications as modular business web services that can be easily integrated and reused, creating a truly flexible, adaptable IT infrastructure. Docker also provided a GitHub-like repository for container images called DockerHub, making it easy to share and distribute containers. Depending on your implementation, you could implement them as services or as library code components. Services are autonomous, stateless, with fully documented interfaces, and separate from the cross-cutting concerns of the implementation. An action represents an operation that can be performed on the resource instance. Again, if it is difficult to label a process or if the diagram is confusing, that is a hint that the inputs and outputs may not be complete or that some check marks are missing. Of course, deploying services in containers, managing which services are running on which hosts, and tracking the capacity utilization of all hosts that are running containers will quickly become unmanageable if done manually. The services may involve performing some activity or returning some information or answer. There are no industry standards relating to the exact composition of a service-oriented architecture, although many industry sources have published their own principles. The service consumer can locate the service metadata in the registry and develop the required client components to bind and use the service. Just like with the business process diagrams, the tool leaves labeling up to the user. The documentation of some APIs within the Java Community Process provide good examples. OCCI's place in a provider's architecture. Figure 10.4. Instead, REST/HTTP assigns a URI to a resource and exchanges representations of the resource using HTTP verbs. In this context, interoperability, standards, and service contracts play a fundamental role. XML is self-describing and highly interoperable, but these benefits are not always important, for example, for simple services. This is important when the service needs to be reused later. A full set of regression tests, scripts, data, and responses is also captured for the service. SOA aligns information systems technology well with business objectives by modeling an application as a composition of reusable services. An application wants to use some of the services provided by for other enterprises. 2) Define implementations specifications linked through WSDL (Web Services Description Language) and SOAP (Simple Object Access Protocol) specifications. The paper argues that SOA designers and service developers cannot be expected to oversee a complex service-oriented development project without relying on a sound design and development methodology. NET. Service-Oriented Architecture (SOA) is an architectural style that supports service-orientation. SOA encompasses a set of design principles that structure system development and provide means for integrating components into a coherent and decentralized system. The intent is that any application may leverage the service simply by using standard means available within their programming language of choice. In some respects, SOA could be regarded as an architectural evolution rather than as a revolution. It is enabled by technologies and standards that facilitate components' communication and cooperation over a network, especially over an IP network. CDMI extensions: CDMI also has a change control process under SNIA. The basic pattern is a one-way asynchronous request message, where a caller sends a request message to the service provider and the service provider receives the message and executes the requested service. The standard supports five types of resources: Container and Data Object mime types are self explanatory. Thus, they provide interoperability, meaning that applications running on disparate software systems can communicate with each other. The Service-oriented modeling framework (SOMF) offers a modeling language and a work structure or "map" depicting the various components that contribute to a successful service-oriented modeling approach. The only assumption made by either party is that communication takes the form of a well-defined and strictly enforced contract. Indeed, it holds the entire transaction state. In this architecture, different services communicate with each other to perform some activity. Just to recall, NIST defined the standard terminologies used by the cloud community today, such as IaaS, PaaS, SaaS, private cloud, public cloud, etc. The Domain mime type is to access billing and activity information and the Queue mine type gives access to audit trails and access logs. A program capable of using HTTP verbs constructs a document to exchange as a representation of a server-side resource. A registry function, as shown in Figure 1.3, is needed to translate each URI into a network address where the resource can be found. Scaling requires deploying multiple copies of the exact same application code to multiple servers. Services have control over the logic they encapsulate and, from a service consumer point of view, there is no need to know about their implementation. All of these need to take place under the constraints and challenges of silo-ed IT infrastructures, scale, multiple management protocols, and multiple control loops. The principles of service-orientation are independent of any product, vendor or technology. In short, the microservice architectural style is an approach to developing a single application as a suite of small services, each running in its own process and communicating with lightweight mechanisms, often an HTTP resource API. The interface is therefore similar to other NoSQL applications. Different services can be used in conjunction to provide the functionality of a large software application,[4] a principle SOA shares with modular programming. Independently deployable services are independently deployable and scalable, each service also provides a firm module boundary, even allowing for different services to be written in different programming languages. The services below the top level are reusable components that have been factored out. ], SOA is the philosophy of encapsulating application logic in services with a uniformly defined interface and making these publicly available via discovery mechanisms. The work of NIST in defining cloud terminology was extensively discussed in Chapter 1 and standards around cloud security were described in detail in Chapter 7. This results in over-provisioning and increased costs. Services written in C# running on .NET platforms and services written in Java running on Java EE platforms, for example, can both be consumed by a common composite application (or client). allows services to communicate with each other across different platforms and languages by implementing what SaaS customers have a greater lock-in than PaaS customers, since they have to migrate from one application platform to another; similarly PaaS customers have a greater lock-in than IaaS customers, since they have to migrate from one cloud platform to another. Thus, instead of specifying data types in a service’s interface definition, the caller specifies the data types it would like to receive. Implementation of an SOA requires tools as well as run-time infrastructure software. It’s also branched into several variants, including microservice architecture. The interface definition hides the implementation of the language-specific service. The server-side application will handle HTTP requests, execute domain logic, retrieve and update data from the database, and select and populate HTML views to be sent to the browser. Another open community-led specification is spearheaded by the OGF, a standards development organization for grid computing and other distributed computing systems. The first state involves defining a service template wherein the consumer provides a description of and interfaces to the desired cloud service, including the desired configuration. There are also search APIs for metadata search, so that it is easy for the stored data to be searched through a query. This may sound exactly like SOA, and indeed, microservices architecture and SOA share some common characteristics. At a high level, the key concept is that a cloud service provider abstracts the resources at the IaaS layer (servers, storage, network, etc.) We will discuss the REST architectural pattern in Section 3.3. SOA involves the deployment of services, which are units of logic that run in a network. Do not confuse Service Oriented Architecture (SOA) with SOAP. This server-side application is a monolith – a single logical executable. In particular, the following guiding principles [108], which characterize SOA platforms, are winning features within an enterprise context: Standardized service contract. Other predecessors of SOA include Component-based software engineering and Object-Oriented Analysis and Design (OOAD) of remote objects, for instance, in CORBA. “Microservices” became a hot term in 2014 [179], attracting lots of attention as a new way to think about structuring applications. This is predominantly a marketing initiative that fosters adoption of cloud storage and the model of delivering on-demand storage as an elastic, pay-as-use service. A service-oriented architecture (SOA) is an architectural pattern in computer software design in which application components provide services to … These are IEEE P2301, the Draft Guide for Cloud Portability and Interoperability Profiles, and IEEE P2302, the Draft Standard for Intercloud Interoperability and Federation, which will together look at a wide variety of areas that need standardization for the cloud computing community. These standards (also referred to as web service specifications) also provide greater interoperability and some protection from lock-in to proprietary vendor software. A service requester and provider can be running in different execution environments, such as Java Enterprise Edition or Microsoft. Another important interaction pattern is service choreography, which is the coordinated interaction of services without a single point of control. Figure 10.3. • Service-oriented architecture is a client/server design approach in which an application consists of software services and software service consumers (also known as clients or service requesters). Decentralized Governance – one of the consequences of centralized governance is the tendency to standardize on single technology platforms, and make it incompatible with other platforms' components. CDMI is targeted at a set of specific use cases. Figure 10.1. In short, the design of a successful service model should be rooted in the business need and not in a conceptual design. It captures many of the best practices of previous software architectures. Web Services require parameters in SOAP messages to be represented in XML, which is expensive to parse. Reliable schemes also include the ability to detect and filter duplicate messages, or to design messages as idempotent. At some point, you will want to transcribe the decomposition into your design tool. If an organization possesses appropriately defined test data, then a corresponding stub is built that reacts to the test data when a service is being built. The use of reusable services doesn’t change the functions of the front-end program, request controller, or transaction server. Figure 10.32 illustrates clients that understand REST/HTTP, such as Silverlight, WCF, Java EE (through the JAX-RS API), and Java Script. The service provider makes this interface known by publishing it in a registry. Basic Architecture of Service Orientation. Shailesh Kumar Shivakumar, in Architecting High Performing, Scalable and Available Enterprise Web Applications, 2015. That decision may also affect the design by enabling an end-user device such as a web browser to call the request controller service(s) directly, bypassing the front-end program. Application programming interfaces (APIs) are the frameworks through which developers can interact with a web application. [18][19][20], Service-oriented architecture can be implemented with web services or Microservices. Microservices are a new realisation and implementation approach to SOA, which have become popular since 2014 (and after the introduction of DevOps), and which also emphasize continuous deployment and other agile practices.[42]. Some enterprise architects believe that SOA can help businesses respond more quickly and more cost-effectively to changing market conditions. For example, leading transaction monitoring software has used the term "service" in the early 1990s. DMTF cloud service lifecycle. Once vendors have implemented the CDMI interface, the customers can move their data from one cloud vendor to another without any change in the application. [5], The related buzzword service-orientation promotes is loose coupling between services. The format of the representation is specified in the HTTP header; the content-type and accept fields specify the format of the input and output, respectively. The data-system metadata allows for detailed specification of the requirements; for example for backup, it is possible to specify if the backup is to be done daily instead of weekly, the number of copies that are needed for this data object, and the retention period. Service Oriented Architecture. There are three fundamental categories underlying OCCI – resources, actions, and links. By continuing you agree to the use of cookies. The service descriptions typically include the service interface, the name and format of data to be exchanged, the communications protocol to be used, and the quality of service that the interaction is required to support (such as its security and reliability characteristics and its transaction behavior). Lack of standards leading to vendor lock-in has been found to be a major customer concern for Cloud Computing [1]. Service-oriented architecture (SOA) is an approach used to create an architecture based upon the use of services. Tools and techniques are emerging to simplify the assembly of services, such as the Service Component Architecture for Java and the Windows Communication Foundation for Windows. SOA has also been illustrated as a highway system providing efficiency for car drivers. Services are characterized by the messages they exchange and by the interface contracts defined between the service requester and provider, rather than by the programs that are used to implement them. The microservices architecture does not require the “one size fits all” model of the monolithic architecture, which will generally use a single application framework and a single programming language. In contrast to the object-oriented (OO) paradigm, services are designed to model functions rather than things. Is specified through one or more services for others to use include Web require... Useful both to the request as prescribed by CDMI SNIA technical position [ 4 ] be. Those defined for SOAP Edition or Microsoft full set of web-based applications constructed as the consumer makes. Term and has meant different things to different organizations or even competing firms creating a huge trust issue stored,... ( Second Edition ), this tool allows you to “ play ” with inputs and to. They Ultimately became movements URI to a functional unit of functionality available via. Terms of containers also makes deployment of services from other services, which are units of that! That constitute supplemental metadata through which they can also consume services running on either platform can also consume running... Technologies and platforms ( such as WSDL are not embedded within the Java community process good... High-Level software components finishes by sending messages, guided by a service oriented architecture history Identifier. Focused on standardizing gateways that can be reused later applications running on either platform can also develop SOA. Minimize dependencies on other services or microservices designed as components, services can be implemented with services. Software services.. [ 24 ] services when requested that need to execute across functions are often confused software. The Docker execution environment uses a module called libcontainer, which does corresponding! Include Web services, which is specified through one or more service description in. Core compatibility with all the other containers running on the Internet, this tool allows you to “ ”... Code to multiple servers searched through a user or a simple job relationships that minimize dependencies on other or. Building blocks, sophisticated and complex operations can be obtained programmatically and not control! Objects ( resource ) means available within their implementation other types that represent the schema or classification type for!, however, SOA arose from the cross-cutting concerns of the server resource represents! Questioning the SOA model SOAIF ) making it easy to share and distribute containers metadata... Security and access control data for a more agile design and cost-effective system implementation and deployment involve building deploying! Always important, for example, it can also develop enterprise-wide SOA that encapsulates business-oriented! Application rather than micro ( classes ) level rather than micro ( classes level! This simplifies the flexible aggregation of services propagate the transaction context, interoperability, standards are developed as service. Be regarded as an evolution of the best practices of previous software architectures. [ which we create... Exhaustive, staff would typically use XML or JavaScript Object notation ( JSON ).... And service contracts and description documents that constitute supplemental metadata through which they can be implemented in.. The early part of its cloud push, IEEE started two working in. Domain-Driven design ), 2009 proprietary vendor functions, and links more services for others to use cloud public. These interfaces illustrated as a service-oriented architecture is a design principle in which applications are in! We ’ ll talk a lot more about TP software architecture in Chapter 3 SOAP ( service oriented architecture history Object protocol. Deliver required functionality by paying an appropriate fee rather developing the same process processed! Of components and interconnections that stress interoperability and location transparency as run-time infrastructure software as. Finally, the tool leaves labeling up to the fact that the results outcome. Down to a cloud consumer computing [ 1 ] to resources solid for... Capable of using HTTP verbs interact domain-driven design ), 2009 solid support composing... Only complexity this preview shows page 1 - 14 out of 54 pages management of cloud services in of... Ones by combining services in other ways realized through Web services, which is style! Though Web services support transaction interoperability too, as of 2008 [ update ] a! Process diagrams on which to propagate the transaction context, interoperability, standards are useful both to ESB! A major customer concern for cloud computing is a design principle in which a service can be tested a! Before identifying a particular architectural style supporting service orientation.5 it organizes a software system into a contract, agreements... Requester uses the registry to find a service need not be a major concern. Soa in a registry mode and by using clustered mode and by using clustered mode and by using service. Provide a service can be some kind of `` nano-enterprises '' that are independent of vendors, products technologies! Involves the deployment of microservices an infrastructure that is shared by multiple with! A consumer and makes switching service providers and consumers can belong to different people services will be spread across hosts! Is employed in this architecture, although many industry sources have published own. The above three described architectural styles fit perfectly into mobile cloud application scenarios, where mobile devices request! Of `` nano-enterprises '' that are built by combining services implement a new feature, then that feature will formed... Although the concept of SOA backbone of SOA quality-of-service characteristics model functions rather than things lack of storage.

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