Welcome!

Microservices Expo Authors: Craig Lowell, Elizabeth White, Sematext Blog, Roger Strukhoff, Pat Romanski

Related Topics: Microservices Expo

Microservices Expo: Article

SOA Book Excerpt: The First-Class Constructs of SOA - Part 3

Services, service components, and flows

In SOA, the main emphasis is on the identification of the right services followed by their specification and realization. Although some might argue that object-oriented analysis and design (OOAD) techniques can be used as a good starting point for services, its main emphasis is on microlevel abstractions. Services, on the other hand, are business-aligned entities and therefore are at a much higher level of abstraction than are objects and components.

In Part 1 of this book excerpt, we discussed the different layers of an SOA Reference Architecture, and in Part 2 we discussed Service Oriented Modeling and Architecture, and Part 3, we move on to the second phase in the method: specification of services.

Specification
The specification phase helps design the details of the three first-class constructs of SOA: services, service components, and flows. It uses a combination of three high-level activities to determine which services to expose, provides a detailed specification for the exposed services, and specifies the flows (processes) and service components. The three activities are called service specification, subsystem analysis, and component specification. From a service model work product standpoint, this phase provides the most content: The service exposure, service dependencies, service composition, service NFRs, service messages, and state management are all addressed in this phase. The rest of this section focuses on the three activities.

Service Specification
Service specification defines the dependencies, composition, exposure decisions, messages, QoS constraints, and decisions regarding the management of state within a service.

The first task concerns service exposure. The service portfolio had an exhaustive list of services obtained through the three techniques that we used for service identification. It is easy to comprehend that this list may contain too many candidate services; not all of them are at the right level of granularity to be exposed as services. Some of the service candidates may be too coarse-grained and might actually be more like business processes or subprocesses rather than individual services (for example, some of the process elements derived from the first level of process decomposition), whereas some others may be too fine-grained IT functions (for example, the process elements in the lowest level of process decomposition and some of the existing system functionality). Deciding to expose the entire list of candidate services is a perfect recipe for following a perfect antipattern in SOA - the service proliferation syndrome (a phenomenon we want to avoid). Some economic and practical considerations limit the exposure of all candidate services. A cost is associated with every service chosen for exposure. The funding of the entire service life cycle, the governance factor around service life-cycle management, and the added underlying infrastructure requirements to support security, scalability, performance, and other nonfunctional requirements make it impractical to follow the rules of economies of scale when it comes to exposing all candidate services.

Based on these premises, we recommend a service litmus test. The test consists of specific criteria applied to the candidate services. Only those services that meet the criteria are chosen for service exposure. The method provides an initial set of test criteria in the following form:

  1. Business alignment: A service must be business aligned. If a service is not, in some shape or form, traceable back to a business goal, it may not be an ideal candidate to be chosen for exposure.
  2. Composability: Tests the ability of a service to be used in a context entirely different from the one from which the service was originally identified. A service should be able to participate in multiple business processes without compromising the NFR compliance requirements for the process.
  3. Feasibility of implementation: Tests the technical feasibility of implementing the service in a cost- and time-effective manner. Practical considerations limit overly complex services to be commissioned for implementation.
  4. Redundancy elimination: Tests whether the service can be used within all processes and applications where its function is required.

More Stories By Tilak Mitra

Tilak Mitra is a Certified Senior IT Architect at IBM. He specializes in mid- to large-range enterprise and application architectures based on J2EE, MQ, and other EAI technologies. You can reach him at [email protected]

More Stories By Norbert Bieberstein

Norbert Bieberstein, solution architect for IBM's Enterprise Integration team, has extensive first-hand experience with customers migrating to SOA-based On-Demand solutions.

More Stories By Keith Jones

Keith Jones, PhD, IT architect at IBM Enterprise Integration Solutions, focuses on helping customers define and implement service-oriented architectures.

More Stories By Robert Laird

Robert Laird is an IT architect in IBM's SOA Advanced Technologies group.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@MicroservicesExpo Stories
A company’s collection of online systems is like a delicate ecosystem – all components must integrate with and complement each other, and one single malfunction in any of them can bring the entire system to a screeching halt. That’s why, when monitoring and analyzing the health of your online systems, you need a broad arsenal of different tools for your different needs. In addition to a wide-angle lens that provides a snapshot of the overall health of your system, you must also have precise, ...
SYS-CON Events announced today that Venafi, the Immune System for the Internet™ and the leading provider of Next Generation Trust Protection, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Venafi is the Immune System for the Internet™ that protects the foundation of all cybersecurity – cryptographic keys and digital certificates – so they can’t be misused by bad guys in attacks...
Monitoring of Docker environments is challenging. Why? Because each container typically runs a single process, has its own environment, utilizes virtual networks, or has various methods of managing storage. Traditional monitoring solutions take metrics from each server and applications they run. These servers and applications running on them are typically very static, with very long uptimes. Docker deployments are different: a set of containers may run many applications, all sharing the resource...
Cloud Expo 2016 New York at the Javits Center New York was characterized by increased attendance and a new focus on operations. These were both encouraging signs for all involved in Cloud Computing and all that it touches. As Conference Chair, I work with the Cloud Expo team to structure three keynotes, numerous general sessions, and more than 150 breakout sessions along 10 tracks. Our job is to balance the state of enterprise IT today with the trends that will be commonplace tomorrow. Mobile...
Using new techniques of information modeling, indexing, and processing, new cloud-based systems can support cloud-based workloads previously not possible for high-throughput insurance, banking, and case-based applications. In his session at 18th Cloud Expo, John Newton, CTO, Founder and Chairman of Alfresco, described how to scale cloud-based content management repositories to store, manage, and retrieve billions of documents and related information with fast and linear scalability. He addres...
The 19th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportuni...
To leverage Continuous Delivery, enterprises must consider impacts that span functional silos, as well as applications that touch older, slower moving components. Managing the many dependencies can cause slowdowns. See how to achieve continuous delivery in the enterprise.
DevOps at Cloud Expo – being held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA – announces that its Call for Papers is open. Born out of proven success in agile development, cloud computing, and process automation, DevOps is a macro trend you cannot afford to miss. From showcase success stories from early adopters and web-scale businesses, DevOps is expanding to organizations of all sizes, including the world's largest enterprises – and delivering real results. Am...

Modern organizations face great challenges as they embrace innovation and integrate new tools and services. They begin to mature and move away from the complacency of maintaining traditional technologies and systems that only solve individual, siloed problems and work “well enough.” In order to build...

The post Gearing up for Digital Transformation appeared first on Aug. 24, 2016 11:45 AM EDT  Reads: 1,280

SYS-CON Events announced today that eCube Systems, a leading provider of middleware modernization, integration, and management solutions, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. eCube Systems offers a family of middleware evolution products and services that maximize return on technology investment by leveraging existing technical equity to meet evolving business needs. ...
DevOps at Cloud Expo, taking place Nov 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long dev...
The following fictional case study is a composite of actual horror stories I’ve heard over the years. Unfortunately, this scenario often occurs when in-house integration teams take on the complexities of DevOps and ALM integration with an enterprise service bus (ESB) or custom integration. It is written from the perspective of an enterprise architect tasked with leading an organization’s effort to adopt Agile to become more competitive. The company has turned to Scaled Agile Framework (SAFe) as ...
It's been a busy time for tech's ongoing infatuation with containers. Amazon just announced EC2 Container Registry to simply container management. The new Azure container service taps into Microsoft's partnership with Docker and Mesosphere. You know when there's a standard for containers on the table there's money on the table, too. Everyone is talking containers because they reduce a ton of development-related challenges and make it much easier to move across production and testing environm...
As the world moves toward more DevOps and Microservices, application deployment to the cloud ought to become a lot simpler. The Microservices architecture, which is the basis of many new age distributed systems such as OpenStack, NetFlix and so on, is at the heart of Cloud Foundry - a complete developer-oriented Platform as a Service (PaaS) that is IaaS agnostic and supports vCloud, OpenStack and AWS. Serverless computing is revolutionizing computing. In his session at 19th Cloud Expo, Raghav...
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devices - comp...
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
19th Cloud Expo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterpri...
Akana has announced the availability of version 8 of its API Management solution. The Akana Platform provides an end-to-end API Management solution for designing, implementing, securing, managing, monitoring, and publishing APIs. It is available as a SaaS platform, on-premises, and as a hybrid deployment. Version 8 introduces a lot of new functionality, all aimed at offering customers the richest API Management capabilities in a way that is easier than ever for API and app developers to use.
The burgeoning trends around DevOps are translating into new types of IT infrastructure that both developers and operators can take advantage of. The next BriefingsDirect Voice of the Customer thought leadership discussion focuses on the burgeoning trends around DevOps and how that’s translating into new types of IT infrastructure that both developers and operators can take advantage of.
With so much going on in this space you could be forgiven for thinking you were always working with yesterday’s technologies. So much change, so quickly. What do you do if you have to build a solution from the ground up that is expected to live in the field for at least 5-10 years? This is the challenge we faced when we looked to refresh our existing 10-year-old custom hardware stack to measure the fullness of trash cans and compactors.