Cloud Computing, SOA and Windows Azure
Cloud Services with Windows Azure - Part 1
By: Thomas Erl
Aug. 1, 2010 05:45 PM
For a complete list of the co-authors and contributors, see the end of the article.
Microsoft's Software-plus-Services strategy represents a view of the world where the growing feature-set of devices and the increasing ubiquity of the Web are combined to deliver more compelling solutions. Software-plus-Services represents an evolutionary step that is based on existing best practices in IT and extends the application potential of core service-orientation design principles.
Microsoft's efforts to embrace the Software-plus-Services vision are framed by three core goals:
The Windows Azure platform represents one of the major components of the Software-plus-Services strategy, as Microsoft's cloud computing operating environment, designed from the outset to holistically manage pools of computation, storage and networking; all encapsulated by one or more services.
Cloud Computing 101
Cloud computing enables the delivery of scalable and available capabilities by leveraging dynamic and on-demand infrastructure. By leveraging these modern service technology advances and various pervasive Internet technologies, the "cloud" represents an abstraction of services and resources, such that the underlying complexities of the technical implementations are encapsulated and transparent from users and consumer programs interacting with the cloud.
At the most fundamental level, cloud computing impacts two aspects of how people interact with technologies today:
Although cloud computing was originally, and still often is, associated with Web-based applications that can be accessed by end-users via various devices, it is also very much about applications and services themselves being consumers of cloud-based services. This fundamental change is a result of the transformation brought about by the adoption of SOA and Web-based industry standards, allowing for service-oriented and Web-based resources to become universally accessible on the Internet as on-demand services.
One example has been an approach whereby programmatic access to popular functions on Web properties is provided by simplifying efforts at integrating public-facing services and resource-based interactions, often via RESTful interfaces. This was also termed "Web-oriented architecture" or "WOA," and was considered a subset of SOA. Architectural views such as this assisted in establishing the Web-as-a-platform concept, and helped shed light on the increasing inter-connected potential of the Web as a massive collection (or cloud) of ready-to-use and always-available capabilities.
This view can fundamentally change the way services are designed and constructed, as we reuse not only someone else's code and data, but also their infrastructure resources, and leverage them as part of our own service implementations. We do not need to understand the inner workings and technical details of these services; Service Abstraction (696), as a principle, is applied to its fullest extent by hiding implementation details behind clouds.
SOA Principles and Patterns
With regards to service delivery, we are focused on the actual design, development, and implementation of cloud-based services. Let's begin by establishing high-level characteristics that a cloud computing environment can include:
Fundamental topics regarding service delivery pertain to the cloud deployment model used to provide the hosting environment and the service delivery model that represents the functional nature of a given cloud-based service. The next two sections explore these two types of models.
Cloud Deployment Models
Let's briefly discuss these deployment models individually.
Essential characteristics of a public cloud typically include:
Note that public clouds can host individual services or collections of services, allow for the deployment of service compositions, and even entire service inventories.
Essential characteristics of a private cloud typically include:
Other Deployment Models
The Intercloud (Cloud of Clouds)
Figure 1: Examples of how vendors establish a commercial intercloud
From a services consumption perspective, we can look at the intercloud as an on-demand SOA environment where useful services managed by other organizations can be leveraged and composed. In other words, services that are outside of an organization's own boundaries and operated and managed by others can become a part of the aggregate portfolio of services of those same organizations.
Deployment Models and Windows Azure
Service Delivery Models
Other Delivery Models
Note: Cloud deployment models and service delivery models are covered in more detail in the upcoming book SOA & Cloud Computing as part of the Prentice Hall Service-Oriented Computing Series from Thomas Erl. This book will also introduce several new design patterns related to cloud-based service, composition, and platform design.
IaaS vs. PaaS
Figure 2: Common Differentiations Between Delivery Models
We interact with PaaS at a higher abstraction level than with IaaS. This means we manage less of the infrastructure and assume simplified administration responsibilities. But at the same time, we have less control over this type of environment.
IaaS provides a similar infrastructure to traditional on-premise environments, but we may need to assume the responsibility to re-architect an application in order to effectively leverage platform service clouds. In the end, PaaS will generally achieve a higher level of scalability and reliability for hosted services.
An on-premise infrastructure is like having your own car. You have complete control over when and where you want to drive it, but you are also responsible for its operation and maintenance. IaaS is like using a car rental service. You still have control over when and where you want to go, but you don't need to be concerned with the vehicle's maintenance. PaaS is more comparable to public transportation. It is easier to use as you don't need to know how to operate it and it costs less. However, you don't have control over its operation, schedule, or routes.
• • •
This excerpt is from the book, "SOA with .NET & Windows Azure: Realizing Service-Orientation with the Microsoft Platform", edited and co-authored by Thomas Erl, with David Chou, John deVadoss, Nitin Ghandi, Hanu Kommapalati, Brian Loesgen, Christoph Schittko, Herbjörn Wilhelmsen, and Mickie Williams, with additional contributions from Scott Golightly, Daryl Hogan, Jeff King, and Scott Seely, published by Prentice Hall Professional, June 2010, ISBN 0131582313, Copyright 2010 SOA Systems Inc. For a complete Table of Contents please visit: www.informit.com/title/0131582313
John deVadoss leads the Patterns & Practices team at Microsoft and is based in Redmond, WA.
Thomas Erl is the world's top-selling SOA author, series editor of the Prentice Hall Service-Oriented Computing Series from Thomas Erl (www.soabooks.com), and editor of the SOA Magazine (www.soamag.com).
Nitin Gandhi is an enterprise architect and an independent software consultant, based in Vancouver, BC.
Hanu Kommalapati is a Principal Platform Strategy Advisor for a Microsoft Developer and Platform Evangelism team based in North America.
Brian Loesgen is a Principal SOA Architect with Microsoft, based in San Diego. His extensive experience includes building sophisticated enterprise, ESB and SOA solutions.
Christoph Schittko is an architect for Microsoft, based in Texas. His focus is to work with customers to build innovative solutions that combine software + services for cutting edge user experiences and the leveraging of service-oriented architecture (SOA) solutions.
Herbjörn Wilhelmsen is a consultant at Forefront Consulting Group, based in Stockholm, Sweden. His main areas of focus are Service-Oriented Architecture, Cloud Computing and Business Architecture.
Mickey Williams leads the Technology Platform Group at Neudesic, based in Laguna Hills,
Darryl Hogan is an architect with more than 15 years experience in the IT industry. Darryl has gained significant practical experience during his career as a consultant, technical evangelist and architect.
As a Senior Technical Product Manager at Microsoft, Kris works with customers, partners, and industry analysts to ensure the next generation of Microsoft technology meets customers' requirements for building distributed, service-oriented solutions.
Jeff King has been working with the Windows Azure platform since its first announcement at PDC 2008 and works with Windows Azure early adopter customers in the Windows Azure TAP
Scott Seely is co-founder of Tech in the Middle, www.techinthemiddle.com, and president of Friseton, LLC,
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