Service autonomy is a design principle that is applied within the

service-orientation Service-orientation is a design paradigm for computer software in the form of services. The principles of service-oriented design stress the separation of concerns in the software. Applying service-orientation results in units of software partiti ...

design paradigm A design is a plan or specification for the construction of an object or system or for the implementation of an activity or process or the result of that plan or specification in the form of a prototype, product, or process. The verb ''to design'' ...

, to provide

services Service may refer to: Activities * Administrative service, a required part of the workload of university faculty * Civil service, the body of employees of a government * Community service, volunteer service for the benefit of a community or a p ...

with improved independence from their execution environments.Wojciech Cellary,Sergiusz Strykowsk
E-Government Based on Cloud Computing and Service-Oriented Architecture
Online].Date accessed: 17 April 2010. This results in greater reliability, since services can operate with less dependence on resources over which there is little or no control.

Purpose

The service-orientation design paradigm emphasizes service reuse as dictated by the Service reusability principle, service reusability design principle. Under this paradigm of a heavily reused services, reliability becomes critical to ensure service longevity. In turn, service reliability depends on the service's operational control of service logic and underlying implementation resources to reduce dependence on external resources over which it has little or no control such as shared service logic or a shared database, which may not be available when required by the service. Traditional component-based software development also faces the same autonomy requirements, the provisioning of autonomy and reliability, in such circumstances, is left to the actual run-time environment e.g. by providing fail-over support or by deploying a solution on dedicated servers. However, within service-orientation, the stakes are even higher as a service-oriented solution can be composed of services

Application

The application of service autonomy involves two types of autonomy that allow an increase the overall autonomy of the service, design time autonomy and run time autonomy.

Design-time autonomy

Design-time autonomy refers to the independence with which the services could be evolved without impacting their service consumers. This type of autonomy is required as the service's underlying legacy resources might need an overhaul or the service's logic might need refactoring in order to make it more efficient. The application of the

service loose coupling Service may refer to: Activities * Administrative service, a required part of the workload of university faculty * Civil service, the body of employees of a government * Community service, volunteer service for the benefit of a community or a p ...

and the

service abstraction Service abstraction is a design principle that is applied within the service-orientation design paradigm so that the information published in a service contract is limited to what is required to effectively utilize the service The service contract s ...

principles helps in attaining design-time autonomy as their application results in services whose contracts are shielded from their logic and implementation and hence, the services could be redesigned without affecting their service consumers.

Run-time autonomy

Run-time autonomy refers to the extent of the control that a service has over the way its solution logic Service-orientation Principles nlineDate accessed: 17 April 2010. is processed by the run-time environment. The more control a service has over its run-time environment, the more predictable is its behavior. Run-time autonomy is achieved by providing dedicated processing resources to the service. For example, if the service logic performs memory intensive tasks then the service could be deployed to a server with reserved or conserved resources. Similarly, by providing locally cached copies of data, where applicable, the service's dependency on a remote shared database can be reduced. As a result, the overall autonomy of the service is increased... There is a direct relationship between run-time autonomy and the design-time autonomy. Increasing the design-time autonomy automatically increases the ability to evolve service's implementation environment.

Service types

Although increasing service autonomy to the maximum extent is always desirable, it is not always possible to design each and every service with maximum design-time and run-time autonomy. As a result, the services need to be prioritized so that their autonomy could be addressed according to their value for business. This could be done by having a look at the functional context of the service. Services whose functional contexts are independent of any particular business process, e.g. entity Utility Service
/ref> services, are good candidates for increasing their autonomy. This is because they offer functionality that is of interest to different types of consumers. On the other hand, business process specific services, e.g. task