Welcome!

Microservices Expo Authors: Elizabeth White, Charles Araujo, Liz McMillan, Pat Romanski, Flint Brenton

Related Topics: Microservices Expo, Agile Computing

Microservices Expo: Article

SOA and the Rise of WOA

A lightweight version of SOA has arrived: Web-Oriented Architecture or WOA

Paul Wallis's Blog

How does SOA work, how can it be used? And what is WOA? With the use of a real-world example,this article describes why a properly planned and implemented Service Oriented Architecture can create a flexible way of aligning business and IT. Paul Wallis, of Stroma Software (UK) Ltd, explains...


Over the past year or so there has been a huge increase in the amount of discussion about Service Oriented Architecture (SOA), and the number of blogs and posts on the subject seems to increase daily.

So with over 25 million references to SOA discovered by Google, why bother writing another SOA blog post?

Much of the discussion amongst the SOA community is interesting to other technophiles, but only serves to confuse the majority of readers. Bloggers like Mike Kavis try to bring the focus of SOA back to a business perspective, but the vast majority of articles concentrate on the technology debate.

In recent weeks the rise of a lightweight version of SOA, termed Web Oriented Architecture (WOA), has had the techno-bloggers tapping away at their keyboards. OnStrategies gives us a quick digest of some of the highlights.

Rather than join the technology debate about SOA we’ll take a step back and explain simply how it works, how it can be used and, with the use of a real-world example, describe why a properly planned and implemented Service Oriented Architecture can create a flexible way of aligning business and IT.

Let’s start by looking at what the term Service Oriented Architecture actually means.

The original definition of the word “architecture” can be described as “the art and science of designing and constructing physical structures”. Typically we associate the word “architecture” with the style of buildings, be it the Art Deco style of the Chrysler Building in New York, the modernist formalism of the Bank of China Tower in Hong Kong, or the grand scale of the gothic Milan Cathedral.

Recently the IT industry has used the term Architecture more and more frequently to describe how building blocks of hardware, software and interface protocols can be put together to create systems. The best recent description of its usage that I have seen described Architecture as:

“a subjective mapping from a human perspective (that of the user in the case of abstract or physical artifacts) to the elements or components of some kind of structure or system, which preserves the relationships among the elements or components.”

When it comes to Service Oriented Architecture (SOA), the term means designing a system where each system component provides access to its computational or business resources as a service to other components.

By way of explanation, let’s say that we have a simplified system which receives an order, generates an invoice and faxes it to the purchaser. The workflow of that function can be broken down into four distinct services:

1) Stock availability and pricing service
2) Order creation service
3) Document creation service
4) Faxing service

The theory is that by creating these distinct, separate and self contained services for each of the components we gain greater flexibility. Each of these services could be called from other business functions allowing re-use in subsequent areas of the business.

For example, the business could offer potential clients access to its stock availability and pricing information rather than utilising its own sales staff to process queries. Or it could expand the faxing service to cover email without changes to multiple larger systems - saving money, time and resources.

That, put very simply, forms the basis of all SOA. Those of you familiar with software development will recognise the re-use advantages of this approach which has been the main-stay of functional and object oriented design for many years.

So if this concept of re-use is not new, why all the hype surrounding SOA?

Although the concept is not new, software re-use traditionally required the code to be “tightly coupled”, meaning that the programmers had to understand how both the new code and the re-usable code could be linked together to create an interface which tied them explicitly together. Vendors are now trying to promote the technology, tools and standards that have been developed to allow services to be “loosely coupled” with each other, reducing the complexity of integrating services together. To understand how this works we need to look at how the service industries work in the real world.

Over the past few decades we have seen a growth in the service industry sector, driven partly by economic constraints. Companies have increasingly analysed their strengths and been concentrating on their core expertise, outsourcing those functions that they see as non-core and awarding contracts to companies to service those contracts. Remember in the 1980’s when the telephone sanitiser companies had the contract for wiping telephone handsets, or in the 1990’s when plant maintenance companies came in to water the peace lilies in the foyer?

Usually, each of these contracts would have an associated cost negotiated before the contract was awarded, and was subject to procurement rigours for value for money. They would also of had predefined deliverables and be monitored to ensure the service matched those promised. Finally, each contract commonly had a point of contact for efficient communication with that service organisation.

By building similar capabilities into SOA, the IT industry now has a way of creating re-usable services which can be used by third parties seeking “buy not build” functionality for their applications or for the support of their business functions. By implementing a standard contract approach into the implementation of services, they can be used without a detailed knowledge of bespoke interface considerations. As such, it is relatively easy to decouple from one service provider and move to another, hence the term “loosely coupled” as opposed to “tightly coupled”.

As well as adhering to a contract model and having the ability to be loosely coupled, services generally also allow abstraction, reusability, autonomy, statelessness, discoverability, and composability – depending on the specification and design brief of the service.

Architecture

When an architect is commissioned to design a building his first requirement is a design brief. As well as understanding the style of the building, he must also gain knowledge of budget, environmental considerations, location specific requirements, building usage, decision authority, material availability, reasons for embarking on the project etc.

The answers to these questions will determine how the building will look and feel. It will also, however, determine the tools and equipment needed to undertake the task, the best approach to take, what skills are required to deliver the project, the scope of work, bill of materials and project timescales.

The same is true of SOA. Just as there is more than one way to design and construct a building, and more than one set of tools which can be used, so with SOA there are many technologies and methodologies which can be used to deliver an SOA solution and all have different advantages and disadvantages.

In the construction industry there are some people who prefer sustainable hardwood construction rather than metal. Within the proponents of metal construction, there are some which prefer aluminium to steel. Within the advocates of steel, some prefer rivets to welding.

Similarly, in the SOA community some advocates prefer SOAP/web services to CORBA, DCOM, REST, RPC or JINI. Some prefer complex messaging backbones and others simple state protocol transmissions. Some prefer closely coupled, others loosely coupled. Some use a top-down approach to architectural design, whilst others suggest bottom up.

Does it matter? Yes it does.

Which is best? Unfortunately that depends on your design brief.

SOA Architecture Principles

There are some well defined specific SOA architectural principles governing service design and service definition, namely:

  • Service encapsulation - Many web-services are consolidated to be used under the SOA Architecture. Often such services have not been planned to be under SOA.
  • Service loose coupling - Services maintain a relationship that minimizes dependencies and only requires that they maintain an awareness of each other
  • Service contract - Services adhere to a communications agreement, as defined collectively by one or more service description documents
  • Service abstraction - Beyond what is described in the service contract, services hide logic from the outside world
  • Service reusability - Logic is divided into services with the intention of promoting reuse
  • Service composability - Collections of services can be coordinated and assembled to form composite services
  • Service autonomy – Services have control over the logic they encapsulate
  • Service optimization – All else equal, high-quality services are generally considered preferable to low-quality ones
  • Service discoverability – Services are designed to be outwardly descriptive so that they can be found and accessed via available discovery mechanisms such as service repositories or directories

Further information about these principles can be found here.

There are two approaches to Service Orientated Modelling – “top-down” and “bottom-up”. The top-down approach starts with analysis at a business process level to evaluate re-engineering and workflow, ensuring that service delivery matches business requirements. The “bottom-up” approach starts in the IT stack, analysing systems and system functionality, before existing systems are wrapped using Web services to create a service layer.

In reality, despite much debate over a number of years, success will not come from “top-down” OR “bottom-up”. It is only a mixture of the two which will work effectively, a view shared by Neil Ward-Dutton in his recent post “Which comes first: process or service?

Next Page: A Real-Life example...

More Stories By Paul Wallis

Paul Wallis is Chief Technology Officer at Stroma Software Limited. He blogs at www.keystonesandrivets.com, where he tries to bridge the understanding gap between business and IT.

Comments (1) View Comments

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.


Most Recent Comments
kvandersluis 12/04/08 11:48:04 PM EST

Great intro to SOA, Paul. You mention in the summary that budget cuts may stifle SOA for many companies. But SOA-related infrastructure and tooling is an area of rapid growth in open source development, not only with the project I work with (xaware.org), but at companies like WSO2, and many Apache projects like Synapse and Tuscany. Companies can find value in service orientation at the project level before taking on the all-encompassing, enterprise-wide SOA initiative. Open source facilitates this without the huge investment of many of the commercial platforms.

-Kirstan

@MicroservicesExpo Stories
The next XaaS is CICDaaS. Why? Because CICD saves developers a huge amount of time. CD is an especially great option for projects that require multiple and frequent contributions to be integrated. But… securing CICD best practices is an emerging, essential, yet little understood practice for DevOps teams and their Cloud Service Providers. The only way to get CICD to work in a highly secure environment takes collaboration, patience and persistence. Building CICD in the cloud requires rigorous ar...
"This all sounds great. But it's just not realistic." This is what a group of five senior IT executives told me during a workshop I held not long ago. We were working through an exercise on the organizational characteristics necessary to successfully execute a digital transformation, and the group was doing their ‘readout.' The executives loved everything we discussed and agreed that if such an environment existed, it would make transformation much easier. They just didn't believe it was reali...
Your homes and cars can be automated and self-serviced. Why can't your storage? From simply asking questions to analyze and troubleshoot your infrastructure, to provisioning storage with snapshots, recovery and replication, your wildest sci-fi dream has come true. In his session at @DevOpsSummit at 20th Cloud Expo, Dan Florea, Director of Product Management at Tintri, provided a ChatOps demo where you can talk to your storage and manage it from anywhere, through Slack and similar services with...
Containers are rapidly finding their way into enterprise data centers, but change is difficult. How do enterprises transform their architecture with technologies like containers without losing the reliable components of their current solutions? In his session at @DevOpsSummit at 21st Cloud Expo, Tony Campbell, Director, Educational Services at CoreOS, will explore the challenges organizations are facing today as they move to containers and go over how Kubernetes applications can deploy with lega...
The “Digital Era” is forcing us to engage with new methods to build, operate and maintain applications. This transformation also implies an evolution to more and more intelligent applications to better engage with the customers, while creating significant market differentiators. In both cases, the cloud has become a key enabler to embrace this digital revolution. So, moving to the cloud is no longer the question; the new questions are HOW and WHEN. To make this equation even more complex, most ...
Learn how to solve the problem of keeping files in sync between multiple Docker containers. In his session at 16th Cloud Expo, Aaron Brongersma, Senior Infrastructure Engineer at Modulus, discussed using rsync, GlusterFS, EBS and Bit Torrent Sync. He broke down the tools that are needed to help create a seamless user experience. In the end, can we have an environment where we can easily move Docker containers, servers, and volumes without impacting our applications? He shared his results so yo...
Don’t go chasing waterfall … development, that is. According to a recent post by Madison Moore on Medium featuring insights from several software delivery industry leaders, waterfall is – while still popular – not the best way to win in the marketplace. With methodologies like Agile, DevOps and Continuous Delivery becoming ever more prominent over the past 15 years or so, waterfall is old news. Or, is it? Moore cites a recent study by Gartner: “According to Gartner’s IT Key Metrics Data report, ...
Kubernetes is a new and revolutionary open-sourced system for managing containers across multiple hosts in a cluster. Ansible is a simple IT automation tool for just about any requirement for reproducible environments. In his session at @DevOpsSummit at 18th Cloud Expo, Patrick Galbraith, a principal engineer at HPE, discussed how to build a fully functional Kubernetes cluster on a number of virtual machines or bare-metal hosts. Also included will be a brief demonstration of running a Galera MyS...
Enterprise architects are increasingly adopting multi-cloud strategies as they seek to utilize existing data center assets, leverage the advantages of cloud computing and avoid cloud vendor lock-in. This requires a globally aware traffic management strategy that can monitor infrastructure health across data centers and end-user experience globally, while responding to control changes and system specification at the speed of today’s DevOps teams. In his session at 20th Cloud Expo, Josh Gray, Chie...
Many organizations are now looking to DevOps maturity models to gauge their DevOps adoption and compare their maturity to their peers. However, as enterprise organizations rush to adopt DevOps, moving past experimentation to embrace it at scale, they are in danger of falling into the trap that they have fallen into time and time again. Unfortunately, we've seen this movie before, and we know how it ends: badly.
Agile has finally jumped the technology shark, expanding outside the software world. Enterprises are now increasingly adopting Agile practices across their organizations in order to successfully navigate the disruptive waters that threaten to drown them. In our quest for establishing change as a core competency in our organizations, this business-centric notion of Agile is an essential component of Agile Digital Transformation. In the years since the publication of the Agile Manifesto, the conn...
"I focus on what we are calling CAST Highlight, which is our SaaS application portfolio analysis tool. It is an extremely lightweight tool that can integrate with pretty much any build process right now," explained Andrew Siegmund, Application Migration Specialist for CAST, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
In IT, we sometimes coin terms for things before we know exactly what they are and how they’ll be used. The resulting terms may capture a common set of aspirations and goals – as “cloud” did broadly for on-demand, self-service, and flexible computing. But such a term can also lump together diverse and even competing practices, technologies, and priorities to the point where important distinctions are glossed over and lost.
"I will be talking about ChatOps and ChatOps as a way to solve some problems in the DevOps space," explained Himanshu Chhetri, CTO of Addteq, in this SYS-CON.tv interview at @DevOpsSummit at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
For organizations that have amassed large sums of software complexity, taking a microservices approach is the first step toward DevOps and continuous improvement / development. Integrating system-level analysis with microservices makes it easier to change and add functionality to applications at any time without the increase of risk. Before you start big transformation projects or a cloud migration, make sure these changes won’t take down your entire organization.
The Jevons Paradox suggests that when technological advances increase efficiency of a resource, it results in an overall increase in consumption. Writing on the increased use of coal as a result of technological improvements, 19th-century economist William Stanley Jevons found that these improvements led to the development of new ways to utilize coal. In his session at 19th Cloud Expo, Mark Thiele, Chief Strategy Officer for Apcera, compared the Jevons Paradox to modern-day enterprise IT, examin...
The taxi industry never saw Uber coming. Startups are a threat to incumbents like never before, and a major enabler for startups is that they are instantly “cloud ready.” If innovation moves at the pace of IT, then your company is in trouble. Why? Because your data center will not keep up with frenetic pace AWS, Microsoft and Google are rolling out new capabilities. In his session at 20th Cloud Expo, Don Browning, VP of Cloud Architecture at Turner, posited that disruption is inevitable for comp...
When you focus on a journey from up-close, you look at your own technical and cultural history and how you changed it for the benefit of the customer. This was our starting point: too many integration issues, 13 SWP days and very long cycles. It was evident that in this fast-paced industry we could no longer afford this reality. We needed something that would take us beyond reducing the development lifecycles, CI and Agile methodologies. We made a fundamental difference, even changed our culture...
High-velocity engineering teams are applying not only continuous delivery processes, but also lessons in experimentation from established leaders like Amazon, Netflix, and Facebook. These companies have made experimentation a foundation for their release processes, allowing them to try out major feature releases and redesigns within smaller groups before making them broadly available. In his session at 21st Cloud Expo, Brian Lucas, Senior Staff Engineer at Optimizely, discussed how by using ne...
In his session at 20th Cloud Expo, Mike Johnston, an infrastructure engineer at Supergiant.io, discussed how to use Kubernetes to set up a SaaS infrastructure for your business. Mike Johnston is an infrastructure engineer at Supergiant.io with over 12 years of experience designing, deploying, and maintaining server and workstation infrastructure at all scales. He has experience with brick and mortar data centers as well as cloud providers like Digital Ocean, Amazon Web Services, and Rackspace. H...