Welcome!

Agile Computing Authors: Sanjay Uppal, Liz McMillan, James Carlini, Peter Silva, SmartBear Blog

Related Topics: @CloudExpo, Microservices Expo, Microsoft Cloud

@CloudExpo: Article

Cloud Computing, SOA and Windows Azure - Part 2

SOA Principles and Patterns

For a complete list of the co-authors and contributors, see the end of the article.

Windows Azure Platform Overview
The Windows Azure platform is an Internet-scale cloud computing services platform hosted in Microsoft data centers. Windows tools provide functionality to build solutions that include a cloud services operating system and a set of developer services. The key parts of the Windows Azure platform are:

  • Windows Azure (application container)
  • Microsoft SQL Azure
  • Windows Azure platform AppFabric

The infrastructure and service architectures that underlie many of these native services (as well as cloud-based services in general) are based on direct combined application of Stateful Services [786] and Redundant Implementation [766]. This is made possible by leveraging several of the built-in extensions and mechanisms provided by the Windows Azure platform (as explained in this chapter and Chapter 16).

The Windows Azure platform is part of the Microsoft cloud, which consists of multiple categories of services:

  • Cloud-based applications: These are services that are always available and highly scalable. They run in the Microsoft cloud that consumers can directly utilize. Examples include Bing, Windows Live Hotmail, Office Live, etc.
  • Software services: These services are hosted instances of Microsoft's enterprise server products that consumers can use directly. Examples include Exchange Online, SharePoint Online, Office Communications Online, etc.
  • Platform services: This is where the Windows Azure platform itself is positioned. It serves as an application platform public cloud that developers can use to deploy next-generation, Internet-scale, and always available solutions.
  • Infrastructure services: There is a limited set of elements of the Windows Azure platform that can support cloud-based infrastructure resources.

Figure 3 illustrates the service categories related to the Windows Azure platform. Given that Windows Azure is itself a platform, let's explore it as an implementation of the PaaS delivery model.

Figure 3: A high-level representation of categories of services available in the Windows Azure cloud

The Windows Azure platform was built from the ground up using Microsoft technologies, such as the Windows Server Hyper-V-based system virtualization layer. However, the Windows Azure platform is not intended to be just another off-premise Windows Server hosting environment. It has a cloud fabric layer, called the Windows Azure Fabric Controller, built on top of its underlying infrastructure.

The Windows Azure Fabric Controller pools an array of virtualized Windows Server instances into a logical entity and automatically manages the following:

  • Resources
  • Load balancing
  • Fault-tolerance
  • Geo-replication
  • Application lifecycle

These are managed without requiring the hosted applications to explicitly deal with the details. The fabric layer provides a parallel management system that abstracts the complexities in the infrastructure and presents a cloud environment that is inherently elastic. As a form of PaaS, it also supports the access points for user and application interactions with the Windows Azure platform.

The Windows Azure platform essentially provides a set of cloud-based services that are symmetric with existing mainstream on-site enterprise application platforms (see Figure 4).

Figure 4: An overview of common Windows Azure platform capabilities

For example:

  • Storage services: A scalable distributed data storage system that supports many types of storage models, including hash map or table-like structured data, large binary files, asynchronous messaging queues, traditional file systems, and content distribution networks
  • Compute services: Application containers that support existing mainstream development technologies and frameworks, including .NET, Java, PHP, Python, Ruby on Rails, and native code.
  • Data services: Highly reliable and scalable relational database services that also support integration and data synchronization capabilities with existing on-premise relational databases
  • Connectivity services: These are provided via a cloud-based service bus that can be used as a message intermediary to broker connections with other cloud-based services and services behind firewalls within on-premise enterprise environments
  • Security services: Policy-driven access control services that are federation-aware and can seamlessly integrate with existing on-premise identity management systems
  • Framework services: Components and tools that support specific aspects and requirements of solution frameworks
  • Application services: Higher-level services that can be used to support application development, such as application and data marketplaces

All of these capabilities can be utilized individually or in combination.

Windows Azure (Application Container)
Windows Azure serves as the development, service hosting, and service management environment. It provides the application container into which code and logic, such as Visual Studio projects, can be deployed. The application environment is similar to existing Windows Server environments. In fact, most .NET projects can be deployed directly without significant changes.

A Windows Azure instance represents a unit of deployment, and is mapped to specific virtual machines with a range of variable sizes. Physical provisioning of the Windows Azure instances is handled by the cloud fabric. We are required only to specify, by policy, how many instances we want the cloud fabric to deploy for a given service.

We have the ability to manually start and shut down instances, and grow or shrink the deployment pool; however, the cloud fabric also provides automated management of the health and lifecycles of instances. For example, in the event of an instance failure, the cloud fabric would automatically shut down the instance and attempt to bring it back up on another node.

Windows Azure also provides a set of storage services that consumers can use to store and manage persistent and transient data. Storage services support geo-location and offer high durability of data by triple-replicating everything within a cluster and across data centers. Furthermore, they can manage scalability requirements by automatically partitioning and load balancing services across servers.

Also supported by Windows Azure is a VHD-based deployment model as an option to enable some IaaS requirements. This is primarily geared for services that require closer integration with the Windows Server OS. This option provides more control over the service hosting environment and can better support legacy applications.
Services deployed within Windows Azure containers and made available via Windows Azure instances establish service architectures that, on the surface, resemble typical Web service or REST service implementations. However, the nature of the back-end processing is highly extensible and scalable and can be further subject to various forms of Service Refactoring [783] over time to accommodate changing usage requirements. This highlights the need for Windows Azure hosted services to maintain the freedom to be independently governed and evolved. This, in turn, places a greater emphasis on the balanced design of the service contract and its proper separation as part of the overall service architecture.

Specifically, it elevates the importance of the Standardized Service Contract (693), Service Loose Coupling (695), and Service Abstraction (696) principles that, through collective application, shape and position service contracts to maximize abstraction and cross-service standardization, while minimizing negative forms of consumer and implementation coupling. Decoupled Contract [735] forms an expected foundation for Windows Azure-hosted service contracts, and there will generally be the need for more specialized contract-centric patterns, such as Validation Abstraction [792], Canonical Schema [718], and Schema Centralization [769].

SQL Azure
SQL Azure is a cloud-based relational database service built on SQL Server technologies that exposes a fault-tolerant, scalable, and multi-tenant database service. SQL Azure does not exist as hosted instances of SQL Server. It also uses a cloud fabric layer to abstract and encapsulate the underlying technologies required for provisioning, server administration, patching, health monitoring, and lifecycle management. We are only required to deal with logical administration tasks, such as schema creation and maintenance, query optimization, and security ­management.

In addition to reliability and scalability improvements, SQL Azure's replication mechanism can be used to apply Service Data Replication [773] in support of the Service Autonomy (699) principle. This is significant, as individual service autonomy within cloud environments can often fluctuate due to the heavy emphasis on shared resources across pools of cloud-based services.

A SQL Azure database instance is actually implemented as three replicas on top of a shared SQL Server infrastructure managed by the cloud fabric. This cloud fabric delivers high availability, reliability, and scalability with automated and transparent replication and failover. It further supports load-balancing of consumer requests and the synchronization of concurrent, incremental changes across the replicas. The cloud fabric also handles concurrency conflict resolutions when performing bi-directional data synchronization between replicas by using built-in policies (such as last-writer-wins) or custom policies.

Because SQL Azure is built on SQL Server, it provides a familiar relational data model and is highly symmetric to on-premise SQL Server implementations. It supports most features available in the regular SQL Server database engine and can also be used with tools like SQL Server 2008 Management Studio, SQLCMD, and BCP, and SQL Server Integration Services for data migration.

Windows Azure Platform AppFabric
In Chapter 7, as part of our coverage of .NET Enterprise Services, we introduced Windows Server AppFabric. This represents the version of AppFabric that is local to the Windows Server environment. Windows Azure platform AppFabric (with the word "platform" intentionally not capitalized), is the cloud-based version of AppFabric that runs on Windows Azure.

Windows Azure platform AppFabric helps connect services within or across clouds and enterprises. It provides a Service Bus for connectivity across networks and organizational boundaries, and an Access Control service for federated authorization as a ­service.

The Service Bus acts as a centralized message broker in the cloud to relay messages between services and service consumers. It has the ability to connect to on-premise services through firewalls, NATs, and over any network topology.

Its features include:

  • Connectivity using standard protocols and standard WCF bindings
  • Multiple communication models (such as publish-and-subscribe, one-way messaging, unicast and multicast datagram distribution, full-duplex bi-directional connection-oriented sessions, peer-to-peer sessions, and end-to-end NAT traversal)
  • Service endpoints that are published and discovered via Internet-accessible URLs
  • Global hierarchical namespaces that are DNS and transport-independent
  • Built-in intrusion detection and protection against denial-of-service attacks

The Windows Azure Service Bus complies to the familiar Enterprise Service Bus [741] compound pattern, and focuses on realizing this pattern across network, security, and organizational domains. Service Bus also provides a service registry to provide registration and discovery of service metadata, which allows for the application of Metadata Centralization [754] and emphasizes the need to apply the Service Discoverability (702) principle.

Access Control acts as a centralized cloud-based security gateway that regulates access to cloud-based services and Service Bus communications, while integrating with standards-based identity providers (including enterprise directories such as Active Directory and online identity systems like Windows Live ID). Access Control and other Windows Azure-related security topics are covered in Chapter 17.

Unlike Windows Azure and SQL Azure, which are based on Windows Server and SQL Server, Access Control Service is not based on an existing server product. It uses technology included in Windows Identity Foundation and is considered a purely cloud-based service built specifically for the Windows Azure platform environment.

Summary of Key Points

  • The Windows Azure platform is primarily a PaaS deployed in a public cloud managed by Microsoft.
  • Windows Azure platform provides a distinct set of capabilities suitable for building scalable and reliable cloud-based services.
  • The overall Windows Azure platform further encompasses SQL Azure and Windows Azure platform AppFabric.

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

Authors
David Chou is a technical architect at Microsoft and is based in Los Angeles. His focus is on collaborating with enterprises and organizations in such areas as cloud computing, SOA, Web, distributed systems, and security.

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,

Contributors
Scott Golightly is currently an Enterprise Solution Strategist with Advaiya, Inc; he is also a Microsoft Regional Director with more than 15 years of experience helping clients to create solutions to business problems with various technologies.

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,

More Stories By Thomas Erl

Thomas Erl is a best-selling IT author and founder of Arcitura Education Inc., a global provider of vendor-neutral educational services and certification that encompasses the Cloud Certified Professional (CCP) and SOA Certified Professional (SOACP) programs from CloudSchool.com™ and SOASchool.com® respectively. Thomas has been the world's top-selling service technology author for nearly a decade and is the series editor of the Prentice Hall Service Technology Series from Thomas Erl, as well as the editor of the Service Technology Magazine. With over 175,000 copies in print world-wide, his eight published books have become international bestsellers and have been formally endorsed by senior members of many major IT organizations and academic institutions. To learn more, visit: www.thomaserl.com

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.


@ThingsExpo Stories
The Quantified Economy represents the total global addressable market (TAM) for IoT that, according to a recent IDC report, will grow to an unprecedented $1.3 trillion by 2019. With this the third wave of the Internet-global proliferation of connected devices, appliances and sensors is poised to take off in 2016. In his session at @ThingsExpo, David McLauchlan, CEO and co-founder of Buddy Platform, will discuss how the ability to access and analyze the massive volume of streaming data from mil...
WebSocket is effectively a persistent and fat pipe that is compatible with a standard web infrastructure; a "TCP for the Web." If you think of WebSocket in this light, there are other more hugely interesting applications of WebSocket than just simply sending data to a browser. In his session at 18th Cloud Expo, Frank Greco, Director of Technology for Kaazing Corporation, will compare other modern web connectivity methods such as HTTP/2, HTTP Streaming, Server-Sent Events and new W3C event APIs ...
SYS-CON Events announced today that Men & Mice, the leading global provider of DNS, DHCP and IP address management overlay solutions, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. The Men & Mice Suite overlay solution is already known for its powerful application in heterogeneous operating environments, enabling enterprises to scale without fuss. Building on a solid range of diverse platform support,...
Eighty percent of a data scientist’s time is spent gathering and cleaning up data, and 80% of all data is unstructured and almost never analyzed. Cognitive computing, in combination with Big Data, is changing the equation by creating data reservoirs and using natural language processing to enable analysis of unstructured data sources. This is impacting every aspect of the analytics profession from how data is mined (and by whom) to how it is delivered. This is not some futuristic vision: it's ha...
Silver Spring Networks, Inc. (NYSE: SSNI) extended its Internet of Things technology platform with performance enhancements to Gen5 – its fifth generation critical infrastructure networking platform. Already delivering nearly 23 million devices on five continents as one of the leading networking providers in the market, Silver Spring announced it is doubling the maximum speed of its Gen5 network to up to 2.4 Mbps, increasing computational performance by 10x, supporting simultaneous mesh communic...
The cloud promises new levels of agility and cost-savings for Big Data, data warehousing and analytics. But it’s challenging to understand all the options – from IaaS and PaaS to newer services like HaaS (Hadoop as a Service) and BDaaS (Big Data as a Service). In her session at @BigDataExpo at @ThingsExpo, Hannah Smalltree, a director at Cazena, will provide an educational overview of emerging “as-a-service” options for Big Data in the cloud. This is critical background for IT and data profes...
With the Apple Watch making its way onto wrists all over the world, it’s only a matter of time before it becomes a staple in the workplace. In fact, Forrester reported that 68 percent of technology and business decision-makers characterize wearables as a top priority for 2015. Recognizing their business value early on, FinancialForce.com was the first to bring ERP to wearables, helping streamline communication across front and back office functions. In his session at @ThingsExpo, Kevin Roberts...
Cognitive Computing is becoming the foundation for a new generation of solutions that have the potential to transform business. Unlike traditional approaches to building solutions, a cognitive computing approach allows the data to help determine the way applications are designed. This contrasts with conventional software development that begins with defining logic based on the current way a business operates. In her session at 18th Cloud Expo, Judith S. Hurwitz, President and CEO of Hurwitz & ...
One of the bewildering things about DevOps is integrating the massive toolchain including the dozens of new tools that seem to crop up every year. Part of DevOps is Continuous Delivery and having a complex toolchain can add additional integration and setup to your developer environment. In his session at @DevOpsSummit at 18th Cloud Expo, Miko Matsumura, Chief Marketing Officer of Gradle Inc., will discuss which tools to use in a developer stack, how to provision the toolchain to minimize onboa...
SYS-CON Events announced today that Interoute, owner-operator of one of Europe's largest networks and a global cloud services platform, has been named “Bronze Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2015 at the Javits Center in New York, New York. Interoute is the owner-operator of one of Europe's largest networks and a global cloud services platform which encompasses 12 data centers, 14 virtual data centers and 31 colocation centers, with connections to 195 ad...
SYS-CON Events announced today that Alert Logic, Inc., the leading provider of Security-as-a-Service solutions for the cloud, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Alert Logic, Inc., provides Security-as-a-Service for on-premises, cloud, and hybrid infrastructures, delivering deep security insight and continuous protection for customers at a lower cost than traditional security solutions. Ful...
Join us at Cloud Expo | @ThingsExpo 2016 – June 7-9 at the Javits Center in New York City and November 1-3 at the Santa Clara Convention Center in Santa Clara, CA – and deliver your unique message in a way that is striking and unforgettable by taking advantage of SYS-CON's unmatched high-impact, result-driven event / media packages.
SYS-CON Events announced today that Commvault, a global leader in enterprise data protection and information management, has been named “Bronze Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY, and the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Commvault is a leading provider of data protection and information management...
With an estimated 50 billion devices connected to the Internet by 2020, several industries will begin to expand their capabilities for retaining end point data at the edge to better utilize the range of data types and sheer volume of M2M data generated by the Internet of Things. In his session at @ThingsExpo, Don DeLoach, CEO and President of Infobright, will discuss the infrastructures businesses will need to implement to handle this explosion of data by providing specific use cases for filte...
SYS-CON Events announced today that Pythian, a global IT services company specializing in helping companies adopt disruptive technologies to optimize revenue-generating systems, has been named “Bronze Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2015 at the Javits Center in New York, New York. Founded in 1997, Pythian is a global IT services company that helps companies compete by adopting disruptive technologies such as cloud, Big Data, advanced analytics, and DevO...
SYS-CON Events announced today that Avere Systems, a leading provider of enterprise storage for the hybrid cloud, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Avere delivers a more modern architectural approach to storage that doesn’t require the overprovisioning of storage capacity to achieve performance, overspending on expensive storage media for inactive data or the overbuilding of data centers ...
Fortunately, meaningful and tangible business cases for IoT are plentiful in a broad array of industries and vertical markets. These range from simple warranty cost reduction for capital intensive assets, to minimizing downtime for vital business tools, to creating feedback loops improving product design, to improving and enhancing enterprise customer experiences. All of these business cases, which will be briefly explored in this session, hinge on cost effectively extracting relevant data from ...
Companies can harness IoT and predictive analytics to sustain business continuity; predict and manage site performance during emergencies; minimize expensive reactive maintenance; and forecast equipment and maintenance budgets and expenditures. Providing cost-effective, uninterrupted service is challenging, particularly for organizations with geographically dispersed operations.
As enterprises work to take advantage of Big Data technologies, they frequently become distracted by product-level decisions. In most new Big Data builds this approach is completely counter-productive: it presupposes tools that may not be a fit for development teams, forces IT to take on the burden of evaluating and maintaining unfamiliar technology, and represents a major up-front expense. In his session at @BigDataExpo at @ThingsExpo, Andrew Warfield, CTO and Co-Founder of Coho Data, will dis...
SYS-CON Events announced today that iDevices®, the preeminent brand in the connected home industry, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. iDevices, the preeminent brand in the connected home industry, has a growing line of HomeKit-enabled products available at the largest retailers worldwide. Through the “Designed with iDevices” co-development program and its custom-built IoT Cloud Infrastruc...