LECTURE 1: INTRODUCTION TO CLOUD COMPUTING ... 6
Essential Characteristics: ... 6
Service Models: ... 7
Deployment Models: ... 7
LECTURE 2: Introducing Windows Azure ... 9
Azure Overview ... 9
Is Your Application a Good Fit for Windows Azure? ... 11
Understand the Benefits of Windows Azure ... 11
Target Scenarios that Leverage the Strengths of Windows Azure ... 12
Scenarios that Do Not Require the Capabilities of Windows Azure... 15
Evaluate Architecture and Development ... 16
Summary... 18
LECTURE 3: Main Components of Windows Azure ... 19
Table of Contents ... 19
The Components of Windows Azure ... 19
Execution Models ... 20 Data Management ... 23 Networking ... 25 Business Analytics ... 27 Messaging ... 29 Caching ... 30 Identity ... 32 High-Performance Computing ... 33 Media ... 33 Commerce ... 34 SDKs ... 35 Getting Started ... 36
Lecture 4: WINDOWS AZURE COMPUTE ... 62
Web Sites vs Cloud Services vs Virtual Machines ... 62
WINDOWS AZURE CLOUD SERVICES: ... Error! Bookmark not defined. WEB ROLE AND WORKER ROLE ... 70
THE THREE RULES OF THE WINDOWS AZURE PROGRAMMING MODEL... 70
A WINDOWS AZURE APPLICATION RUNS MULTIPLE INSTANCES OF EACH ROLE ... 72
A WINDOWS AZURE APPLICATION BEHAVES CORRECTLY WHEN ANY ROLE INSTANCE FAILS . 73 WHAT THE WINDOWS AZURE PROGRAMMING MODEL PROVIDES ... 75
IMPLICATIONS OF THE WINDOWS AZURE PROGRAMMING MODEL: WHAT ELSE CHANGES? . 78 MOVING WINDOWS SERVER APPLICATIONS TO WINDOWS AZURE ... 82
CONCLUSION ... 84
Cloud service concept ... 85
Concepts ... Error! Bookmark not defined. Data Management and Business Analytics ... 88
Table of Contents ... 88
Blob Storage ... 88
Running a DBMS in a Virtual Machine ... 90
SQL Database ... 91
Table Storage ... 96
Hadoop ... 97
Lecture 6: ... 100
Windows Azure SQL Database ... 100
Similarities and Differences ... 100
Compare SQL Server with Windows Azure SQL Database (en-US) ... 103
Table of Contents ... 103
... 103
Similarities and Differences... 103
Logical Administration vs. Physical Administration ... 103
Provisioning ... 103
Transact-SQL Support ... 103
Features and Types ... 103
Key Benefits of the Service ... 103
o Self-Managing ... 103
o High Availability ... 103
o Scalability ... 103
o Familiar Development Model ... 103
See Also ... 103
Other Languages ... 103
Similarities and Differences ... 103
Logical Administration vs. Physical Administration ... 103
Provisioning ... 104
Transact-SQL Support ... 104
Features and Types ... 105
Key Benefits of the Service ... 105
Federations in Windows Azure SQL Database (formerly SQL Azure) ... 109
Federation Architecture ... 109
Design Considerations ... 111
LECTURE 7: ... 125
NETWORKING, CACHING AND ACCESS CONTROL IN WINDOWS AZURE ... 125
Windows Azure Networking ... 125
Table of Contents ... 125
Windows Azure Virtual Network ... 125
Windows Azure Connect ... 127
Windows Azure Traffic Manager ... 129
Caching in Windows Azure ... 131
Caching (Preview) on Roles ... 131
Shared Caching ... 131
In This Section ... Error! Bookmark not defined. Lecture 8: ... 117
WINDOWS AZURE SERVICE BUS ... 117
Software, Services, Clouds, and Devices ... 117
Fulfilling the Potential ... 117
Feature Overview ... 118
Relayed and Brokered Messaging ... 120
Relayed Messaging ... 120
Brokered Messaging ... 121
What are Service Bus Queues ... 121
LECTURE 1: INTRODUCTION TO CLOUD
COMPUTING
(From ―The NIST Definition of Cloud Computing‖)
Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.
This cloud model is composed of five essential characteristics, three service models, and four deployment models.
Essential Characteristics:
On-demand self-service: A consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with each service provider.
Broad network access: Capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, tablets, laptops, and workstations).
Resource pooling: The provider‘s computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand. There is a sense of location independence in that the customer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). Examples of resources include storage, processing, memory, and network bandwidth.
Rapid elasticity: Capabilities can be elastically provisioned and released, in some cases automatically, to scale rapidly outward and inward commensurate with demand. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be appropriated in any quantity at any time.
Measured service: Cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Typically this is done on a pay-per-use or charge-per-use basis. Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and
A cloud infrastructure is the collection of hardware and software that enables the five essential characteristics of cloud computing. The cloud infrastructure can be viewed as containing both a physical layer and an abstraction layer. The physical layer consists of the hardware resources that are necessary to support the cloud services being provided, and typically includes server, storage and network components. The
abstraction layer consists of the software deployed across the physical layer, which manifests the essential cloud characteristics. Conceptually the abstraction layer sits above the physical layer.
Service Models:
Software as a Service (SaaS): The capability provided to the consumer is to use the provider‘s applications running on a cloud infrastructure.
The applications are accessible from various client devices through either a thin client interface, such as a web browser (e.g., web-based email), or a program interface. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings. Platform as a Service (PaaS): The capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages, libraries, services, and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage, but has control over the deployed applications and possibly configuration settings for the application-hosting environment.
Infrastructure as a Service (IaaS): The capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing
resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, and deployed applications; and possibly limited control of select networking components (e.g., host firewalls).
Private cloud. The cloud infrastructure is provisioned for exclusive use by a single organization comprising multiple consumers (e.g., business units). It may be owned, managed, and operated by the organization, a third party, or some combination of them, and it may exist on or off premises.
Community cloud. The cloud infrastructure is provisioned for exclusive use by a specific community of consumers from organizations that have shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be owned, managed, and operated by one or more of the organizations in the community, a third party, or some combination of them, and it may exist on or off premises.
Public cloud. The cloud infrastructure is provisioned for open use by the general public. It may be owned, managed, and operated by a business, academic, or government organization, or some combination of them. It exists on the premises of the cloud provider.
Hybrid cloud. The cloud infrastructure is a composition of two or more distinct cloud infrastructures (private, community, or public) that remain unique entities, but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load balancing between clouds).
LECTURE 2: Introducing Windows
Azure
Azure Overview
Windows Azure is an open and flexible cloud platform that enables you to quickly build, deploy and manage applications across a global network of Microsoft-managed datacenters. You can build applications using any language, tool or framework. And you can integrate your public cloud applications with your existing IT environment.
Always up. Always on.
Windows Azure delivers a 99.95% monthly SLA and enables you to build and run highly available applications without focusing on the infrastructure. It provides automatic OS and service patching, built in network load balancing and resiliency to hardware failure. It supports a deployment model that enables you to upgrade your application without downtime.
Open
Windows Azure enables you to use any language, framework, or tool to build applications. Features and services are exposed using open REST protocols. The Windows Azure client libraries are available for multiple programming languages, and are released under an open source license and hosted on GitHub.
Unlimited servers. Unlimited storage.
Windows Azure enables you to easily scale your applications to any size. It is a fully automated self-service platform that allows you to provision resources within minutes. Elastically grow or shrink your resource usage based on your needs. You only pay for the resources your application uses. Windows Azure is available in multiple datacenters around the world, enabling you to deploy your applications close to your customers.
Powerful Capabilities
Windows Azure delivers a flexible cloud platform that can satisfy any application need. It enables you to reliably host and scale out your application code within compute roles. You can store data using relational SQL databases, NoSQL table stores, and unstructured blob
stores, and optionally use Hadoop and business intelligence services to data-mine it. You can take advantage of Windows Azure‘s robust messaging capabilities to enable scalable
distributed applications, as well as deliver hybrid solutions that run across a cloud and on-premises enterprise environment. Windows Azure‘s distributed caching and CDN services allow you to reduce latency and deliver great application performance anywhere in the world.
Is Your Application a Good Fit for Windows Azure?
If you're considering using Windows Azure to host an application, you might wonder if your application or business requirements are best served by the platform. This topic attempts to answer this question by:
Looking at the benefits Windows Azure provides to your application Applying the strengths of the platform to common scenarios
Rejecting scenarios that do not leverage the strengths of the platform Examining some common architecture and development considerations
The intent is to provide a framework for thinking about your application and how it relates to the capabilities of Windows Azure. In many cases, links to additional
resources are provided to improve your ability to analyze your application and make a decision on how to move to the cloud.
Understand the Benefits of Windows Azure
Before you can determine if your application is well-suited for Windows Azure, you must first understand some of the main benefits of the platform. A complete list of benefits can be found in the Windows Azure documentation and many articles and videos about Windows Azure. One excellent paper on this subject is Cloud
Optimization – Expanding Capabilities, while Aligning Computing and Business Needs.
There are several benefits to having hardware and infrastructure resources managed for you. Let's look at a few of these benefits at a high level before we discuss
scenarios that take advantage of these features.
Resource Management
When you deploy your application and services to the cloud, Windows Azure provides the necessary virtual machines, network bandwidth, and other infrastructure
resources. If machines go down for hardware updates or due to unexpected failures, new virtual machines are automatically located for your application.
Because you only pay for what you use, you can start off with a smaller investment rather than incurring the typical upfront costs required for an on-premises
deployment. This can be especially useful for small companies. In an on-premises scenario, these organizations might not have the data center space, IT skills, or hardware skills necessary to successfully deploy their applications. The automatic infrastructure services provided by Windows Azure offer a low barrier of entry for application deployment and management.
Dynamic scaling refers to the capability to both scale out and scale back your application depending on resource requirements. This is also referred to as elastic scale. Before describing how this works, you should understand the basic architecture of a Windows Azure application. In Windows Azure, you create roles that work
together to implement your application logic. For example, one web role could host the ASP.NET front-end of your application, and one or more worker roles could perform necessary background tasks. Each role is hosted on one or more virtual machines, called role instances, in the Windows Azure data center. Requests are load balanced across these instances. For more information about roles, see the paper The Windows Azure Programming Model.
If resource demands increase, new role instances running your application code can be provisioned to handle the load. When demand decreases, these instances can be removed so that you don't have to pay for unnecessary computing power. This is much different from an on-premises deployment where hardware must be over-provisioned to anticipate peak demands. This scaling does not happen automatically, but it is easily achieved through either the web portal or the Service Management API. The paper Dynamically Scaling an Application demonstrates one way to automatically scale Windows Azure applications. There is also an Autoscaling Application
Block created by the Microsoft Patterns and Practices team.
If your application requires fluctuating or unpredictable demands for computing resources, Windows Azure allows you to easily adjust your resource utilization to match the load.
High Availability and Durability
Windows Azure provides a platform for highly available applications that can reliably store and access backend data through storage services or Windows Azure SQL Database.
First Windows Azure ensures high availability of your compute resources when you have multiple instances of each role. Role instances are automatically monitored, so it is able to respond quickly to hardware restarts or failures by automatically deploying a role to a new instance.
Second, Windows Azure ensures high availability and durability for data stored
through one of the storage services. Windows Azure storage services replicate all data to at least three different servers. Similarly, SQL Database replicates all data to
guarantee availability and durability.
Other Windows Azure services provide similar high availability guarantees. For more information, see theWindows Azure SLA.
Target Scenarios that Leverage the Strengths of Windows
Azure
With an understanding of the strengths of the Windows Azure platform, you can begin to look at the scenarios that are best suited for the cloud. The following
sections discuss several of these patterns and how Windows Azure is ideally suited for certain workloads and goals. The video Windows Azure Design Patterns explains many of the scenarios below and provides a good overview of the Windows Azure platform.
Tip
Although there is a focus on application scenarios here, understand that you can choose to use individual services of Windows Azure. For example, if you find that using blob storage solves an application problem, it is possible that the rest of your application remains outside of the Cloud. This is called a hybrid application and is discussed later in this topic.
Highly Available Services
Windows Azure is well-suited to hosting highly available services. Consider an online store deployed in Windows Azure. Because an online store is a revenue generator, it is critical that it stay running. This is accomplished by the service monitoring and
automatic instance management performed in the Windows Azure data center. The online store must also stay responsive to customer demand. This is accomplished by the elastic scaling ability of Windows Azure. During peak shopping times, new
instances can come online to handle the increased usage. In addition, the online store must not lose orders or fail to completely process placed orders. Windows Azure storage and SQL Database both provide highly available and durable storage options to hold the order details and state throughout the order lifecycle.
Periodic Workloads
Another good fit for Windows Azure is some form of an "on and off" workload. Some applications do not need to run continuously. One simple example of this is a demo or utility application that you want to make available only for several days or weeks. Windows Azure allows you to easily create, deploy, and share that application with the world. But once its purpose is accomplished, you can remove the application and you are only charged for the time it was deployed.
Note
Note: You must remove the deployment, not just suspend the application, to avoid charges for compute time.
Also consider a large company that runs complex data analysis of sales numbers at the end of each month. Although processing-intensive, the total time required to complete the analysis is at most two days. In an on-premises scenario, the servers required for this work would be underutilized for the majority of the month. In
is running in the cloud. And assuming the architecture of the application is designed for parallel processing, the scale out features of Windows Azure could enable the company to create large numbers of worker role instances to complete more complex work in less time. In this example, you should use code or scripting to automatically deploy the application at the appropriate time each month.
Unpredictable Growth
All businesses have a goal of rapid and sustainable growth. But growth is very hard to handle in the traditional on-premises model. If the expected growth does not
materialize, you've spent money maintaining underutilized hardware and infrastructure. But if growth happens more quickly than expected, you might be unable to handle the load, resulting in lost business and poor customer experience. For small companies, there might not even be enough initial capital to prepare for or keep up with rapid growth.
Windows Azure is ideal for handling this situation. Consider a small sports news web site that makes money from advertising. The amount of revenue is directly
proportional to the amount of traffic that the site generates. In this example, initial capital for the venture is limited, and they do not have the money required to setup and run their own data center. By designing the web site to run on Windows Azure, they can easily deploy their solution as an ASP.NET application that uses a backend SQL Database for relational data and blob storage for pictures and videos. If the popularity of the web site grows dramatically, they can increase the number of web role instances for their front-end or increase the size of the SQL Database. The blob storage has built-in scalability features within Windows Azure. If business decreases, they can remove any unnecessary instances. Because their revenue is proportional to the traffic on the site, Windows Azure helps them to start small, grow fast, and reduce risk.
With Windows Azure, you have complete control to determine how aggressively to manage your computing costs. You could decide to use the Service Management API or the Autoscaling Application Block to create an automatic scaling engine that creates and removes instances based on custom rules. You could choose to vary the number of instances based on a predetermined amount, such as four instances during business hours versus two instances during non-business hours. Or you could keep the number of instances constant and only increase them manually through the web portal as demand increases over time. Windows Azure gives you the flexibility to make the decisions that are right for your business.
Workload Spikes
This is another workload pattern that requires elastic scale. Consider the previous example of a sports news web site. Even as their business is steadily growing, there is still the possibility of temporary spikes or bursts of activity. For example, if they are referenced by another popular news outlet, the numbers of visitors to their site could dramatically increase in a single day. In a more predictable scenario, major sporting events and sports championships will result in more activity on their site.
An alternative example is a service that processes daily reports at the end of the day. When the business day closes, each office sends in a report which is processed at the company headquarters. Since the process needs to be active only a few hours each day, it is also a candidate for elastic scaling and deployment.
Windows Azure is well suited for temporarily scaling out an application to handle spikes in load and then scaling back again after the event has passed.
Infrastructure Offloading
As demonstrated in the previous examples, many of the most common cloud scenarios take advantage of the elastic scale of Windows Azure. However, even applications with steady workload patterns can realize cost savings in Windows Azure. It is expensive to manage your own data center, especially when you consider the cost of energy, people-skills, hardware, software licensing, and facilities. It is also hard to understand how costs are tied to individual applications. In Windows Azure, the goal is to reduce total costs as well as to make those costs more transparent. The paper, Cloud Optimization – Expanding Capabilities, while Aligning Computing and Business Needs, does a great job of explaining typical on-premises hosting costs and how these can be reduced with Windows Azure. Windows Azure also provides a pricing calculator for understanding specific costs and a TCO (Total Cost of
Ownership) calculator for estimating the overall cost reduction that could occur by adopting Windows Azure. For links to these calculator tools and other pricing information, see the Windows Azure web site.
Scenarios that Do Not Require the Capabilities of Windows
Azure
Not all applications should be moved to the cloud. Only applications that benefit from Windows Azure features should be moved to the cloud.
A good example of this would be a personal blog website intended for friends and family. A site like this might contain articles and photographs. Although you could use Windows Azure for this project, there are several reasons why Windows Azure is not the best choice. First, even though the site might only receive a few hits a day, one role instance would have to be continuously running to handles those few requests (note that two instances would be required to achieve the Windows Azure SLA for compute). In Windows Azure, the cost is based on the amount of time that each role instance has been deployed (this is known in Windows Azure nomenclature
as compute time); suspending an application does not suspend the consumption of (and charge for) compute time. Even if this site responded to only one hit during the day, it would still be charged for 24 hours of compute time. In a sense, this is rented space on the virtual machine that is running your code. So, at the time of writing this topic, even one extra small instance of a web role would cost $30 a month. And if 20 GB of pictures were stored in blob storage, that storage plus transactions and
bandwidth could add another $6 to the cost. The monthly cost of hosting this type of site on Windows Azure is higher than the cost of a simple web hosting solution from
a third party. Most importantly, this type of web site does not require resource management, dynamic scaling, high availability, and durability.
Windows Azure allows you to choose only the options that are suited to your business‘ needs. For example, you might find instances in which certain data cannot be hosted in the cloud for legal or regulatory reasons. In these cases, you might consider a hybrid solution, where only certain data or specific parts of your application that are not as sensitive and need to be highly available are hosted in Windows Azure.
There are other scenarios that are not well-suited to Windows Azure. By
understanding the strengths of Windows Azure, you can recognize applications or parts of an application that will not leverage these strengths. You can then more successfully develop the overall solution that most effectively utilizes Windows Azure capabilities.
Evaluate Architecture and Development
Of course, evaluating a move to Windows Azure involves more than just knowing that your application or business goals are well-suited for the cloud. It is also important to evaluate architectural and development characteristics of your existing or new
application. A quick way to start this analysis is to use the Microsoft Assessment Tool (MAT) for Windows Azure. This tool asks questions to determine the types of issues you might have in moving to Windows Azure. Next to each question is a link called "See full consideration", which provides additional information about that specific area in Windows Azure. These questions and the additional information can help to identify potential changes to the design of your existing or new application in the cloud.
In addition to the MAT tool, you should have a solid understanding of the basics of the Windows Azure platform. This includes an understanding of common design patterns for the platform. Start by reviewing the Windows Azure videos or reading some of the introductory white papers, such as The Windows Azure Programming Model. Then review the different services available in Windows Azure and consider how they could factor into your solution. For an overview of the Windows Azure services, see the MSDN documentation.
It is beyond the scope of this paper to cover all of the possible considerations and mitigations for Windows Azure solutions. However, the following table lists four common design considerations along with links to additional resources.
Area Description
Hybrid Solutions
It can be difficult to move complex legacy applications to Windows Azure. There are also sometimes regulatory concerns with storing certain types of data in the cloud. However, it is possible to create hybrid solutions that
connect services hosted by Windows Azure with on-premises applications and data.
There are multiple Windows Azure technologies that support this capability, including Service Bus, Access Control Service, and Windows Azure Connect. For a good video on this subject from October 2010, see Connecting Cloud & On-Premises Apps with the Windows Azure Platform. For hybrid architecture guidance based on real-world customer implementations, see Hybrid Reference Implementation Using BizTalk Server, Windows Azure, Service Bus and Windows Azure SQL Database.
State
Management
If you are moving an existing application to Windows Azure, one of the biggest considerations is state management. Many on-premises
applications store state locally on the hard drive. Other features, such as the default ASP.NET session state, use the memory of the local machine for state management. Although your roles have access to their virtual
machine's local drive space and memory, Windows Azure load balances all requests across all role instances. In addition, your role instance could be taken down and moved at any time (for example, when the machine running the role instance requires an update).
This dynamic management of running role instances is important for the scalability and availability features of Windows Azure. Consequently, application code in the cloud must be designed to store data and state remotely using services such as Windows Azure storage or SQL Database. For more information about storage options, see the resources in the Store and Access Data section of the Windows Azure web site.
Storage Requirements
SQL Database is the relational database solution in Windows Azure. If you currently use SQL Server, the transition to SQL Database should be easier. If you are migrating from another type of database system, there are SQL Server Migration Assistants that can help with this process. For more information on migrating data to SQL Database, see Data Migration to Windows Azure SQL Database: Tools and Techniques.
Also consider Windows Azure storage for durable, highly available, and scalable data storage. One good design pattern is to effectively combine the use of SQL Database and Windows Azure storage tables, queues, and blobs. A common example is to use SQL Database to store a pointer to a blob in Windows Azure storage rather than storing the large binary object in the database itself. This is both efficient and cost-effective. For a
discussion of storage options, see the article onData Storage Offerings on the Windows Azure Platform.
Interoperability The easiest application to design or port to Windows Azure is a .NET application. The Windows Azure SDK and tools for Visual Studio greatly simplify the process of creating Windows Azure applications.
But what if you are using open source software or third-party development languages and tools? The Windows Azure SDK uses a REST API that is interoperable with many other languages. Of course, there are some challenges to address depending on your technology. For some
technologies, you can choose to use a stub .NET project in Visual Studio and overload the Run method for your role. Microsoft provides Windows Azure SDKs for Java and Node.js that you can use to develop and deploy applications. There are also community-created SDKs that interact with Windows Azure. A great resource in this area is the Ineroperability Bridges and Labs Center.
Deploying projects that use open source software can also be a challenge. For example, the following blog post discusses options for deploying Ruby applications on Windows
Azure: http://blogs.msdn.com/b/silverlining/archive/2011/08/29/deploying-ruby-java-python-and-node-js-applications-to-windows-azure.aspx. The important point is that Windows Azure is accessible from a variety of languages, so you should look into the options for your particular
language of choice before determining whether the application is a good candidate for Windows Azure.
Beyond these issues, you can learn a lot about potential development challenges and solutions by reviewing content on migrating applications to Windows Azure. The Patterns and Practices group at Microsoft published the following guidance on migration: Moving Applications to the Cloud on the Microsoft Windows Azure Platform. You can find additional resources on migration from the Windows Azure web site: Migrate Services and Data.
Summary
Windows Azure offers a platform for creating and managing highly scalable and available services. You pay only for the resources that you require and then scale them up and down at any time. And you don't have to own the hardware or supporting infrastructure to do this. If your business can leverage the platform to increase agility, lower costs, or lower risk, then Windows Azure is a good fit for your application. After making this determination, you can then look at specific
architecture and development options for using the platform. This includes decisions about new development, migration, or hybrid scenarios. At the end of this analysis, you should have the necessary information to make an informed decision about how to most effectively use Windows Azure to reach your business goals.
LECTURE 3:
Main Components of Windows Azure
Windows Azure is Microsoft's application platform for the public cloud. You can use this platform in many different ways. For instance, you can use Windows Azure to build a web application that runs and stores its data in Microsoft datacenters. You can use Windows Azure just to store data, with the applications that use this data running on-premises (that is, outside the public cloud). You can use Windows Azure to create virtual machines fordevelopment and test or to run SharePoint and other applications. You can use Windows Azure to build massively scalable applications with lots and lots of users. Because the platform offers a wide range of services, all of these things-and more-are possible. To do any of them, though, you need to understand the basics. Even if you don't know anything about cloud computing, this article will walk you through the fundamentals of Windows Azure. The goal is to give you a foundation for understanding and using this cloud platform.
Table of Contents
The Components of Windows Azure Execution Models Data Management Networking Business Analytics Messaging Caching Identity High-Performance Computing (HPC) Media Commerce SDKs Getting Started
The Components of Windows Azure
To understand what Windows Azure offers, it's useful to group its services into distinct categories. Figure 1 shows one way to do this.
Figure 1: Windows Azure provides Internet-accessible application services running in Microsoft datacenters.
To get started with Windows Azure, you need to know at least the basics about each of its components. The rest of this article walks through the technologies shown in the figure, describing what each one offers and when you might use it.
Execution Models
One of the most basic things a cloud platform does is execute applications. Windows Azure provides three options for doing this, as Figure 2 shows.
Figure 2: Windows Azure provides Infrastructure as a Service (IaaS), web hosting, and Platform as a Service (PaaS).
Each of these three approaches-Virtual Machines, Web Sites, and Cloud Services-can be used separately. You can also combine them to create an application that uses two or more of these options together.
Virtual Machines
The ability to create a virtual machine on demand, whether from a standard image or from one you supply, can be very useful. Add the ability to pay for this VM by the hour, and it's even more useful. This approach, commonly known as Infrastructure as a Service (IaaS), is what Windows Azure Virtual Machines provides.
To create a VM, you specify which VHD to use and the VM's size. You then pay for each hour the VM is running. As Figure 2 shows, Windows Azure Virtual Machines offers a gallery of standard VHDs. These include Microsoft-provided options, such as Windows Server 2008 R2, Windows Server 2012, and Windows Server 2008 R2 with SQL Server, along with Linux images provided by Microsoft partners. You're free to upload and create VMs from your own VHDs as well.
Wherever the image comes from, you can persistently store any changes made while a VM is running. The next time you create a VM from that VHD, things pick up where you left off. It's also possible to copy the changed VHD out of Windows Azure, then run it locally.
Windows Azure VMs can be used in many different ways. You might use them to create an inexpensive development and test platform that you can shut down when you've finished using it. You might also create and run applications that use whatever languages and libraries you like. Those applications can use any of the data management options that
Windows Azure provides, and you can also choose to use SQL Server or another DBMS running in one or more virtual machines. Another option is to use Windows Azure VMs as an extension of your on-premises datacenter, running SharePoint or other applications. To support this, it's possible to create Windows domains in the cloud by running Active Directory in Windows Azure VMs. This quite general approach to cloud computing can be used to address many different problems. What you do is up to you.
Web Sites
One of the most common things that people do in the cloud is run websites and web applications. Windows Azure Virtual Machines allows this, but it still leaves you with the responsibility of administering one or more VMs. What if you just want a website where somebody else takes care of the administrative work for you?
This is exactly what Windows Azure Web Sites provides. This execution model offers a managed web environment using Internet Information Services (IIS). You can move an existing IIS website into Windows Azure Web Sites unchanged, or you can create a new one directly in the cloud. Once a website is running, you can add or remove instances
dynamically, relying on Web Sites to load balance requests across them. And as Figure 2 shows, Windows Azure Web Sites offers both a shared option, where your website runs in a virtual machine with other sites, and a way for a site to run in its own VM.
Windows Azure Web Sites is intended to be useful for both developers and web design agencies. For development, it supports .NET, PHP, and Node.js, along with SQL Database and (from ClearDB, a Microsoft partner) MySQL for relational storage. It also provides built-in support for several popular applications, including WordPress, Joomla, and Drupal. The goal is to provide a low-cost, scalable, and broadly useful platform for creating websites and web applications in the public cloud.
Cloud Services
Suppose you want to build a cloud application that can support lots of simultaneous users, doesn't require much administration, and never goes down. You might be an established software vendor, for example, that's decided to embrace Software as a Service (SaaS) by building a version of one of your applications in the cloud. Or you might be a start-up
creating a consumer application that you expect will grow fast. If you're building on Windows Azure, which execution model should you use?
Windows Azure Web Sites allows creating this kind of web application, but there are some constraints. You don't have administrative access, for example, which means that you can't install arbitrary software. Windows Azure Virtual Machines gives you lots of flexibility, including administrative access, and you certainly can use it to build a very scalable
application, but you'll have to handle many aspects of reliability and administration yourself. What you'd like is an option that gives you the control you need but also handles most of the work required for reliability and administration.
This is exactly what's provided by Windows Azure Cloud Services. This technology is designed expressly to support scalable, reliable, and low-admin applications, and it's an example of what's commonly called Platform as a Service (PaaS). To use it, you create an application using the technology you choose, such as C#, Java, PHP, Python, Node.js, or something else. Your code then executes in virtual machines (referred to as instances) running a version of Windows Server.
But these VMs are distinct from the ones you create with Windows Azure Virtual Machines. For one thing, Windows Azure itself manages them, doing things like installing operating system patches and automatically rolling out new patched images. (This implies that your application shouldn't maintain state in web or worker role instances; it should instead be kept in one of the Windows Azure data management options described in the next section.) Windows Azure also monitors the VMs, restarting any that fail.
As Figure 2 shows, you have two roles to choose from when you create an instance, both based on Windows Server. The main difference between the two is that an instance of a web role runs IIS, while an instance of a worker role does not. Both are managed in the same way, however, and it's common for an application to use both. For example, a web role instance might accept requests from users, then pass them to a worker role instance for processing. To scale your application up or down, you can request that Windows Azure create more instances of either role or shut down existing instances. And just like Windows Azure Virtual Machines, you're charged by the hour for each web or worker role instance.
Each of the three Windows Azure execution models has its own role to play. Windows Azure Virtual Machines provides a general-purpose computing environment, Windows Azure Web Sites offers low-cost web hosting, and Windows Azure Cloud Services is the best choice for creating scalable, reliable applications with low administration costs. And as mentioned earlier, you can use these technologies separately or combine them as needed to create the right foundation for your application. The approach you choose depends on what problems you're trying to solve.
Data Management
Applications need data, and different kinds of applications need different kinds of data. Because of this, Windows Azure provides several different ways to store and manage data. One of these has already been mentioned: the ability to run SQL Server or another DBMS in a VM created with Windows Azure Virtual Machines. (It's important to realize that this option isn't limited to relational systems; you're also free to run NoSQL technologies such as
MongoDB and Cassandra.) Running your own database system is straightforward-it replicates what we're used to in our own datacenters-but it also requires handling the administration of that DBMS. To make life easier, Windows Azure provides three data management options that are largely managed for you. Figure 3 shows the choices.
Figure 3: For data management, Windows Azure provides relational storage, scalable NoSQL tables, and unstructured binary storage.
Each of the three options addresses a different need: relational storage, fast access to potentially large amounts of simple typed data, and unstructured binary storage. In all three cases, data is automatically replicated across three different computers in a Windows Azure datacenter to provide high availability. It's also worth pointing out that all three options can be accessed either by Windows Azure applications or by applications running elsewhere, such as your on-premises datacenter, your laptop, or your phone. And however you apply them, you pay for all Windows Azure data management services based on usage, including a gigabyte-per-month charge for stored data.
SQL Database
For relational storage, Windows Azure provides SQL Database. Formerly called SQL Azure, SQL Database provides all of the key features of a relational database management system, including atomic transactions, concurrent data access by multiple users with data integrity, ANSI SQL queries, and a familiar programming model. Like SQL Server, SQL Database can be accessed using Entity Framework, ADO.NET, JDBC, and other familiar data access
technologies. It also supports most of the T-SQL language, along with SQL Server tools such as SQL Server Management Studio. For anybody familiar with SQL Server (or another
relational database), using SQL Database is straightforward.
But SQL Database isn't just a DBMS in the cloud-it's a PaaS service. You still control your data and who can access it, but SQL Database takes care of the administrative grunt work, such as managing the hardware infrastructure and automatically keeping the database and operating system software up to date. SQL Database also provides a federation option that distributes data across multiple servers. This is useful for applications that work with large amounts of data or need to spread data access requests across multiple servers for better performance. If you're creating a Windows Azure application (using any of the three execution models) that needs relational storage, SQL Database can be a good option. Applications running outside the cloud can also use this service, though, so there are plenty of other scenarios. For instance, data stored in SQL Database can be accessed from different client systems,
including desktops, laptops, tablets, and phones. And because it provides built-in high availability through replication, using SQL Database can help minimize downtime.
Tables
Suppose you want to create a Windows Azure application that needs fast access to typed data, maybe lots of it, but doesn't need to perform complex SQL queries on this data. For example, imagine you're creating a consumer application that needs to store customer profile information for each user. Your app is going to be very popular, so you need to allow for lots of data, but you won't do much with this data beyond storing it, then retrieving it in simple ways. This is exactly the kind of scenario where Windows Azure Tables makes sense. Don't be confused by the name: this technology doesn't provide relational storage. (In fact, it's an example of a NoSQL approach called a key/value store.) Instead, Windows Azure Tables let an application store properties of various types, such as strings, integers, and dates. An application can then retrieve a group of properties by providing a unique key for that group. While complex operations like joins aren't supported, tables offer fast access to typed data. They're also very scalable, with a single table able to hold as much as a terabyte of data. And matching their simplicity, tables are usually less expensive to use than SQL Database's relational storage.
Blobs
The third option for data management, Windows Azure Blobs, is designed to store
unstructured binary data. Like Tables, Blobs provides inexpensive storage, and a single blob can be as large as one terabyte. An application that stores video, for example, or backup data or other binary information can use blobs for simple, cheap storage. Windows Azure
applications can also use Windows Azure drives, which let blobs provide persistent storage for a Windows file system mounted in a Windows Azure instance. The application sees ordinary Windows files, but the contents are actually stored in a blob.
Networking
Windows Azure runs today in several datacenters spread across the United States, Europe, and Asia. When you run an application or store data, you can select one or more of these datacenters to use. You can also connect to these datacenters in various ways:
You can use Windows Azure Virtual Network to connect your own on-premises local network to a defined set of Windows Azure VMs.
You can use Windows Azure Connect to link one or more on-premises Windows servers to a specific Windows Azure application.
If your Windows Azure application is running in multiple datacenters, you can use Windows Azure Traffic Manager to route requests from users intelligently across instances of the application.
Figure 4 illustrates these three options.
Figure 4: Windows Azure allows creating a cloud VPN, connecting a Windows Azure application to on-premises machines, and intelligently distributing user requests across different datacenters.
Virtual Network
One useful way to use a public cloud is to treat it as an extension of your own datacenter. Because you can create VMs on demand, then remove them (and stop paying) when they're no longer needed, you can have computing power only when you want it. And since
Windows Azure Virtual Machines lets you can create VMs running SharePoint, Active Directory, and other familiar on-premises software, this approach can work with the applications you already have.
To make this really useful, though, your users ought to be able to treat these applications as if they were running in your own datacenter. This is exactly what Windows Azure Virtual Network allows. Using a VPN gateway device, an administrator can set up a virtual private network (VPN) between your local network and a defined group of VMs running in Windows Azure. Because you assign your own IP v4 addresses to the cloud VMs, they appear to be on your own network. Users in your organization can access the applications those VMs contain as if they were running locally.
Creating a VPN between your local network and a group of VMs in the cloud is useful, but it also requires VPN gateway hardware and the services of a network administrator. Suppose you're a developer who just wants to connect a single Windows Azure application to a specific group of Windows machines within your organization. Perhaps you've built a Cloud Services application that needs to access a database on one of those servers, for example, and you don't want to go to the trouble of configuring a VPN gateway.
Windows Azure Connect is designed for this situation. Connect provides a simple way to establish a secure connection between a Windows Azure application and a group of computers running Windows. A developer just installs the Connect software on the on-premises machines-there's no need to involve a network administrator-and configures the Windows Azure application. Once this is done, the application can communicate with the on-premises computers as if they were on the same local network.
Traffic Manager
A Windows Azure application with users in just a single part of the world might run in only one Windows Azure datacenter. An application with users scattered around the world, however, is more likely to run in multiple datacenters, maybe even all of them. In this second situation, you face a problem: How do you intelligently assign users to application instances? Most of the time, you probably want each user to access the datacenter closest to her, since it will likely give her the best response time. But what if that copy of the application is
overloaded or unavailable? In this case, it would be nice to route her request automatically to another datacenter. This is exactly what's done by Windows Azure Traffic Manager.
The owner of an application defines rules that specify how requests from users should be routed to datacenters, then relies on Traffic Manager to carry out these rules. For example, users might normally be routed to the closest Windows Azure datacenter, but get sent to another one when the response time from their default datacenter exceeds a certain threshold. For globally distributed applications with many users, having a built-in service to handle problems like these is useful.
Business Analytics
Analyzing data is a fundamental part of how businesses use information technology. A cloud platform provides a pool of on-demand, pay-per-use resources, which makes it a good foundation for this kind of computing. Accordingly, Windows Azure provides two options for business analytics. Figure 5 illustrates the choices.
Figure 5: For business analytics, Windows Azure provides reporting and support for big data.
Analyzing data can take many forms, and so these two options are quite different. It's worth looking at each one separately.
SQL Reporting
One of the most common ways to use stored data is to create reports based on that data. To let you do this with data in SQL Database, Windows Azure provides SQL Reporting. A subset of the reporting services included with SQL Server, SQL Reporting lets you build reporting into applications running on Windows Azure or on premises. The reports you create can be in various formats, including HTML, XML, PDF, Excel, and others, and they can be embedded in applications or viewed via a web browser.
Another option for doing analytics with SQL Database data is to use on-premises business intelligence tools. To a client, SQL Database looks like SQL Server, and so the same
technologies can work with both. For example, you're free to use on-premises SQL Server Reporting Services to create reports from SQL Database data.
Hadoop
For many years, the bulk of data analysis has been done on relational data stored in a data warehouse built with a relational DBMS. This kind of business analytics is still important, and it will be for a long time to come. But what if the data you want to analyze is so big that relational databases just can't handle it? And suppose the data isn't relational? It might be server logs in a datacenter, for example, or historical event data from sensors, or something else. In cases like this, you have what's known as a big data problem. You need another approach.
The dominant technology today for analyzing big data is Hadoop. An Apache open source project, this technology stores data using the Hadoop Distributed File System (HDFS), then
lets developers create MapReduce jobs to analyze that data. HDFS spreads data across multiple servers, then runs chunks of the MapReduce job on each one, letting the big data be processed in parallel.
As Figure 5 suggests, the Apache Hadoop-based Service for Windows Azure lets HDFS distribute data across multiple virtual machines, then spreads the logic of a MapReduce job across those VMs. Just as with on-premises Hadoop, data is processed locally-the logic and the data it works on are in the same VM-and in parallel for better performance. The Apache Hadoop-based Service for Windows Azure supports other components of the technology as well, including Hive and Pig, and Microsoft has also created an Excel plug-in for issuing Hive queries.
Messaging
No matter what it's doing, code frequently needs to interact with other code. In some situations, all that's needed is basic queued messaging. In other cases, more complex interactions are required. Windows Azure provides a few different ways to solve these problems. Figure 6 illustrates the choices.
Figure 6: For connecting applications, Windows Azure provides queues, publish/subscribe, and synchronous connections via the cloud.
Queues
Queuing is a simple idea: One application places a message in a queue, and that message is eventually read by another application. If your application needs just this straightforward service, Windows Azure Queues might be the best choice.
One common use of Queues today is to let a web role instance communicate with a worker role instance within the same Cloud Services application. For example, suppose you create a Windows Azure application for video sharing. The application consists of PHP code running in a web role that lets users upload and watch videos, together with a worker role
implemented in C# that translates uploaded video into various formats. When a web role instance gets a new video from a user, it can store the video in a blob, then send a message to a worker role via a queue telling it where to find this new video. A worker role instance-it doesn't matter which one-will then read the message from the queue and carry out the required video translations in the background. Structuring an application in this way allows asynchronous processing, and it also makes the application easier to scale, since the number of web role instances and worker role instances can be varied independently.
Service Bus
Whether they run in the cloud, in your data center, on a mobile device, or somewhere else, applications need to interact. The goal of Windows Azure Service Bus is to let applications running pretty much anywhere exchange data.
As Figure 6 shows, Service Bus provides a queuing service. This service isn't identical to the Queues just described, however. Unlike Windows Azure Queues, for example, Service Bus provides a publish-and-subscribe mechanism. An application can send messages to a topic, while other applications can create subscriptions to this topic. This allows one-to-many communication among a set of applications, letting the same message be read by multiple recipients. And queuing isn't the only option: Service Bus also allows direct communication through its relay service, providing a secure way to interact through firewalls.
Applications that communicate through Service Bus might be Windows Azure applications or software running on some other cloud platform. They can also be applications running outside the cloud, however. For example, think of an airline that implements reservation services in computers inside its own datacenter. The airline needs to expose these services to many clients, including check-in kiosks in airports, reservation agent terminals, and maybe even customers' phones. It might use Service Bus to do this, creating loosely coupled interactions among the various applications.
Caching
Applications tend to access the same data over and over. One way to improve performance is to keep a copy of that data closer to the application, minimizing the time needed to retrieve it. Windows Azure provides two different services for doing this: in-memory caching of data used by Windows Azure applications and a content delivery network (CDN) that caches blob data on disk closer to its users. Figure 7 shows both.
Figure 7: A Windows Azure application can cache data in memory, and copies of a blob can be cached at sites around the world.
Caching
Accessing data stored in any of Windows Azure's data management services-SQL Database, Tables, or Blobs-is quite fast. Yet accessing data stored in memory is even faster. Because of this, keeping an in-memory copy of frequently accessed data can improve application performance. You can use Windows Azure's in-memory Caching to do this.
A Cloud Services application can store data in this cache, then retrieve it directly without needing to access persistent storage. As Figure 7 shows, the cache can be maintained inside your application's VMs or be provided by VMs dedicated solely to caching. In either case, the cache can be distributed, with the data it contains spread across multiple VMs in a Windows Azure datacenter.
An application that repeatedly reads a product catalog might benefit from using this kind of caching, for example, since the data it needs will be available more quickly. The technology also supports locking, letting it be used with read/write as well as read-only data. And ASP.NET applications can use the service to store session data with just a configuration change.
CDN
Suppose you need to store blob data that will be accessed by users around the world. Maybe it's a video of the latest World Cup match, for instance, or driver updates, or a popular
e-book. Storing a copy of the data in multiple Windows Azure datacenters will help, but if there are lots of users, it's probably not enough. For even better performance, you can use the Windows Azure CDN.
The CDN has dozens of sites around the world, each capable of storing copies of Windows Azure blobs. The first time a user in some part of the world accesses a particular blob, the information it contains is copied from a Windows Azure datacenter into local CDN storage in that geography. After this, accesses from that part of the world will use the blob copy cached in the CDN-they won't need to go all the way to the nearest Windows Azure datacenter. The result is faster access to frequently accessed data by users anywhere in the world.
Identity
Working with identity is part of most applications. For example, knowing who a user is lets an application decide how it should interact with that user. To help you do this, Microsoft provides Windows Azure Active Directory.
Like most directory services, Windows Azure Active Directory stores information about users and the organizations they belong to. It lets users log in, then supplies them with tokens they can present to applications to prove their identity. It also allows synchronizing user
information with Windows Server Active Directory running on premises in your local network. While the mechanisms and data formats used by Windows Azure Active Directory aren‘t identical with those used in Windows Server Active Directory, the functions it performs are quite similar.
It's important to understand that Windows Azure Active Directory is designed primarily for use by cloud applications. It can be used by applications running on Windows Azure, for example, or on other cloud platforms. It's also used by Microsoft's own cloud applications, such as those in Office 365. If you want to extend your datacenter into the cloud using Windows Azure Virtual Machines and Windows Azure Virtual Network, however, Windows Azure Active Directory isn't the right choice. Instead, you'll want to run Windows Server Active Directory in cloud VMs, as described earlier.
To let applications access the information it contains, Windows Azure Active Directory provides a RESTful API called Windows Azure Active Directory Graph. This API lets
applications running on any platform access directory objects and the relationships among them. For example, an authorized application might use this API to learn about a user, the groups he belongs to, and other information. Applications can also see relationships between users-their social graph-letting them work more intelligently with the connections among people.
Another capability of this service, Windows Azure Active Directory Access Control, makes it easier for an application to accept identity information from Facebook, Google, Windows Live ID, and other popular identity providers. Rather than requiring the application to understand
the diverse data formats and protocols used by each of these providers, Access Control translates all of them into a single common format. It also lets an application accept logins from one or more Active Directory domains. For example, a vendor providing a SaaS application might use Windows Azure Active Directory Access Control to give users in each of its customers single sign-on to the application.
Directory services are a core underpinning of on-premises computing. It shouldn't be surprising that they're also important in the cloud.
High-Performance Computing
One of the most attractive ways to use a cloud platform is for high-performance computing (HPC), The essence of HPC is executing code on many machines at the same time. On Windows Azure, this means running many virtual machines simultaneously, all working in parallel to solve some problem. Doing this requires some way to schedule applications, i.e., to distribute their work across these instances. To allow this, Windows Azure provides the HPC Scheduler.
This component can work with HPC applications built to use the industry-standard Message Passing Interface (MPI). Software that does finite element analysis, such as car crash
simulations, is one example of this type of application, and there are many others. The HPC Scheduler can also be used with so-called embarrassingly parallel applications, such as Monte Carlo simulations. Whatever problem is addressed, the value it provides is the same: The HPC Scheduler handles the complex problem of scheduling parallel computing work across many Windows Azure virtual machines. The goal is to make it easier to build HPC applications running in the cloud.
Media
Video makes up a large part of Internet traffic today, and that percentage will be even larger tomorrow. Yet providing video on the web isn't simple. There are lots of variables, such as the encoding algorithm and the display resolution of the user's screen. Video also tends to have bursts in demand, like a Saturday night spike when lots of people decide they'd like to watch an online movie.
Given its popularity, it's a safe bet that many new applications will be created that use video. Yet all of them will need to solve some of the same problems, and making each one solve those problems on its own makes no sense. A better approach is to create a platform that provides common solutions for many applications to use. And building this platform in the cloud has some clear advantages. It can be broadly available on a pay-as-you-go basis, and it can also handle the variability in demand that video applications often face.
Windows Azure Media Services addresses this problem. It provides a set of cloud
components that make life easier for people creating and running applications using video and other media. Figure 8 illustrates the technology.
Figure 8: Media Services is a platform for applications that provide video and other media to clients around the world.
As the figure shows, Media Services provides a set of components for applications that work with video and other media. For example, it includes a media ingest component to upload video into Media Services (where it's stored in Windows Azure Blobs), an encoding
component that supports various video and audio formats, a content protection component that provides digital rights management, a component for inserting ads into a video stream, components for streaming, and more. Microsoft partners can also provide components for the platform, then have Microsoft distribute those components and bill on their behalf. Applications that use this platform can run on Windows Azure or elsewhere. For example, a desktop application for a video production house might let its users upload video to Media Services, then process it in various ways. Alternatively, a cloud-based content management service running on Windows Azure might rely on Media Services to process and distribute video. Wherever it runs and whatever it does, each application chooses which components it needs to use, accessing them through RESTful interfaces.
To distribute what it produces, an application can use the Windows Azure CDN, another CDN, or just send bits directly to users. However it gets there, video created using Media Services can be consumed by various client systems, including Windows, Macintosh, HTML 5, iOS, Android, Windows Phone, Flash, and Silverlight. The goal is to make it easier to create modern media applications.
Commerce
The rise of Software as a Service is transforming how we create applications. It's also transforming how we sell applications. Since a SaaS application lives in the cloud, it makes sense that its potential customers should look for solutions online. And this change applies
to data as well as to applications. Why shouldn't people look to the cloud for commercially available datasets? Microsoft addresses both of these concerns with Windows Azure Marketplace, illustrated in Figure 9.
Figure 9: Windows Azure Marketplace lets you find and buy Windows Azure applications and commercial datasets.
Potential customers can search the Marketplace to find Windows Azure applications that meet their needs, then sign up to use them either through the application's creator or directly through the Marketplace. Customers can search the Marketplace for commercial datasets as well, including demographic data, financial data, geographic data, and more. When they find something they like, they can access it either from the vendor or directly through the Marketplace. Applications can also use the Bing Search API through the Marketplace, giving them access to the results of web searches.
SDKs
Back in 2008, the very first pre-release version of Windows Azure supported only .NET development. Today, however, you can create Windows Azure applications in pretty much any language. Microsoft currently provides language-specific SDKs for .NET, Java, PHP, Node.js, and Python. There's also a general Windows Azure SDK that provides basic support for any language, such as C++.
These SDKs help you build, deploy, and manage Windows Azure applications. They're available either from www.windowsazure.com or GitHub, and they can be used with Visual Studio and Eclipse. Windows Azure also offers command line tools that developers can use
with any editor or development environment, including tools for deploying applications to Windows Azure from Linux and Macintosh systems.
Along with helping you build Windows Azure applications, these SDKs also provide client libraries that help you create software running outside the cloud that uses Windows Azure services. For example, you might build an application running at a hoster that relies on Windows Azure blobs, or create a tool that deploys Windows Azure applications through the Windows Azure management interface.
Getting Started
Now that you have the big-picture, the next step is to write your first Windows Azure
application. Choose your language, get the appropriate SDK, and go for it. Cloud computing is the new default--get started now.
