Introducing Windows Azure AppFabric Applications
[This article was contributed by the AppFabric team.]
Posted by Karandeep Anand
Last October, at the PDC 2010 keynote, we shared our vision of building, running, and managing applications reliably and at scale in Windows Azure. Since then, the team has been heads-down to make the vision a reality, and last month at TechEd 2011, we announced that we’ll soon be releasing a rich set of new capabilities to build AppFabric Applications using AppFabric Developer Tools, run them in the AppFabric Container service, and manage them using the AppFabric Application Manager. Today, we are very pleased to announce that the day has come when we can publicly share the first Community Technology Preview (CTP) of these capabilities in Windows Azure! As announced here, the June CTP of AppFabric is now live, and you can start by downloading the new SDK and Developer Tools and by signing up for a free account at the AppFabric Labs portal. Now we’ll go into more detail about what we’ve released today and how you can get started building and managing AppFabric Applications.
Let’s start by defining what we mean when we say AppFabric Applications. In a nutshell, it is any n-tier .NET application that spans the web, middle, and data tiers, composes with external services, and is inherently written to the cloud architecture for scale and availability. In CTP1, we are focusing on a great out-of-box experience for ASP.NET, WCF, and Windows Workflow (WF) applications that consume other Windows Azure services like SQL Azure, AppFabric Caching, AppFabric Service Bus and Azure Storage. The goal is to enable both application developers and ISVs to be able to leverage these technologies to build and manage scalable and highly available applications in the cloud. In addition, the goal is to help both developers and IT Pros, via the AppFabric Developer Tools and AppFabric Application Manager, respectively, to be able to manage the entire lifecycle of an application from coding and testing to deploying and managing.
Now, let’s take a deeper look at the 3 key pieces of the puzzle and how they all fit together to help you through the lifecycle of AppFabric Applications:
- Developer Tools
- AppFabric Container
- Application Manager
AppFabric Developer Tools provide the rich Visual Studio experience at design-time to build and debug AppFabric Applications. The key goal of the Developer Tools is to enable .NET developers to leverage their existing skills and knowledge with the .NET framework and Visual Studio and extend it to build cloud-ready applications in an easy yet rich way for Windows Azure. The Developer Tools are an extension to the existing way of building .NET applications. And the additional tooling allows developers to not only author business and presentation logic that run in the web and middle-tier, but also to easily enrich and extend their apps by composing with other services through a rich service composition experience.
The first goal with Developer Tools is to enable developers to build cloud-ready—i.e. scalable and available—applications by building on concepts they already know. The AppFabric Container service does the heavy lifting of elastically scaling and making an application available and reliable. In Developer Tools, we distilled the set of design principles and configuration knobs that a developer would need to make their application code leverage these capabilities, and we provided these via simple configuration settings on out-of-box components like WCF services and Workflows. In addition, we also provide a powerful programming model to do state management for scalable and resilient stateful services, but more on that topic later. The developer gets to specify intent on the number of scale instances, number of replicas, the partitioning policies etcetera, depending upon how much control they want; or they could go with the default settings and let the runtime manage most of it. In all cases, basic cloud design principles, like address virtualization and automatic address resolution when deployed in Azure, get taken care of automatically, without ever having to think of the underlying compute or network infrastructure.
The second goal is based on a key trend we see today: to be agile and stay competitive, developers want to focus on building code that adds value to their core offering, and therefore want to just use, or compose with, existing services. There is a large ecosystem of existing web services that help with everything from managing basic identity and access, to processing complex multi-party payments across geographies! Hence, service composition is no longer an afterthought but a core part of designing and building an application. Addressing this became one of the key design principles for the AppFabric Developer Tools experience. The tools provide a simple yet powerful experience for composing applications with first party Azure services like Caching or Storage, as well as for consuming external services like Netflix or PayPal. The extensibility of the developer tools allows even the list of service components we ship out of the box to be extended to include 3rd party services, or your own frequently used custom services. The screenshot below shows a list of out-of-box shipping service components like ASP.Net or Caching (in blue) and some example custom service components like Authorize.Net and Facebook (in black).
To get developers started quickly, we are shipping a few templates for building applications using commonly used patterns like a high-performance ASP.NET application using Caching or a rich Silverlight Business Application. These templates get installed as part of the Developer Tools and provide an easy way to get started for building AppFabric applications.
The third key goal is to enable developers to build and debug the application as a whole. No web site or WCF service is an island; each is part of an end to end multi-tier application. AppFabric Developer Tools allow for a local simulation of building and running an application distributed across a web-tier, middle-tier and data-tier—but by building on top of the existing Windows Azure Compute Emulator that Azure developers are already familiar with.
The last design pivot is to enable developers to easily define the end-to-end multi-tier application in terms of the web and middle-tier code artifacts, database and storage resources, and a spectrum of external services referenced by the application. This metadata is automatically captured as the Composition Model. The model then gets packaged along with the application so that the management system (the Application Manager) can use it for managing the application lifecycle easily.
With CTP1, our goal is to first enable the end-to-end developer experience built around these core principles. We’ll build out richer experiences for each step in the development lifecycle as we go through future iterations of the tools.
The AppFabric Container service is the new multi-tenant middle-tier container for hosting and running mid-tier code like WCF and WF, or your custom code, at scale with high availability. At its core, the AppFabric Container consists of a large cluster of machines that have been set up to be resilient, scalable and multi-tenant, and has been pre-provisioned with the necessary frameworks and runtimes required to run your custom code, WCF services or Workflows. With AppFabric Container, we raise the level of abstraction for developers and admins so that they don’t have to deal with any of the complexity of the underlying computing, networking and storage infrastructure. Developers can focus on the business logic, and let the runtime manage the complex details of partitioning, replication, state management, address virtualization, dynamic address resolution, failover, isolation, resiliency, load balancing, request routing etcetera. You simply package and drop your WCF services, Workflows or custom .NET code into the AppFabric Container using the Application Manager or directly from Visual Studio, and let the container host, run and scale the application for you. Then you sit back and manage the service level objectives of your services via the Application Manager.
In addition, the AppFabric Container enables rich hosting scenarios & configurations for both WCF & Windows Workflows (WF). You can build and run brokered services i.e. message activated WCF services, with the integration that AppFabric Container provides with Service Bus. Also, you can run rich WF applications on AppFabric Container with support for persisting state easily and providing business process visibility through the management endpoint to get instance status. We’ll go in to a lot more detail about building WCF & WF applications to run in Windows Azure using AppFabric Container in future blog posts.
The Application Manager is the last piece of the puzzle. It is the infrastructure and tooling that enables you to manage any AppFabric Application through its lifecycle—configuring, deploying, controlling, monitoring, troubleshooting and scaling, all as a single logical application. It uses the metadata of the application i.e. the Composition Model, to automatically understand the components, dependencies and requirements of your multi-tier application so that you don’t have to. The screenshot below shows a sample application that spans the web, middle and data tiers; the application composes with Windows Azure and external 3rd party services, but is being managed as a single unit in the Application Manager.
One of the first things that the Application Manager does when you publish or upload an n-tier application to it is to help you understand the end to end application structure and its contents. It then allows you to centrally configure your entire application and all its parts, including detailed WCF configuration settings—like setting timeouts and number of concurrent connections, or simple environment settings such as which database to connect to in production versus staging. Once you are done configuring the application, a single click allows you to deploy your entire application across multiple web containers and the AppFabric Container. It also wires the application up to all the internal and external referenced services, including, but not limited to, SQL Azure, Caching, Blob Storage, Service Bus Queues etc. And it uses the Access Control Service (ACS) to secure the namespaces. Anyone who has deployed a distributed application spanning multiple tiers understands all the pain that the Application Manager will take away with a single-click! And never once will you have to deal with any virtual machines, network settings or storage configurations.
In addition to centrally configuring and deploying your application, the Application Manager also helps you manage certificates to secure your application, configures the monitoring and diagnostics stores for your app automatically, and creates the right end points and URIs for your deployed services in your namespace.
Other key investments in the Application Manager are in out-of-box monitoring and troubleshooting support for your application. Once you start using your deployed application, you’ll notice a rich set of metrics being automatically generated and collected for your application—everything from basic ASP.NET metrics like number of requests, to request latency numbers for ASP.NET and WCF services, to SQL DB call execution time, to the number of times your cache gets called. All without writing a single line of code during development! And these metrics get aggregated for you across all the instances of your scaled out application, as it is running on the web and AppFabric Container. In addition, if you have built custom components, say for example, a PayPal service that you reference from your application, you can even generate custom metrics in CTP1. You can then start tracking items like the number of orders sent, the number of orders over $1000 processed, and see those custom metrics rendered along with other out-of-box metrics using rich chart controls right in the Application Manager.
On similar lines, we’ve made troubleshooting of your distributed application a lot easier by collecting and centralizing all troubleshooting logs (you get to pick the diagnostics level of the app when you build it) from all the instances of web and AppFabric Container to which the app is deployed to at any given point. All logs are available from one location in the Application Manager, and you can open the downloaded logs in the SvcTraceViewer tool for detailed debugging and diagnosis. You no longer have to write tons of scripts, peer through files, and separate infrastructure issues from application issues. You get all the logs through a UI, and programmatically through our REST API. Yes, we do offer a full REST API (and PowerShell samples too!) to automate, or programmatically access anything that the UI can do, using your own custom dashboards and management tools.
Last but not the least, the Application Manager allows you to scale-out your application with a single-click. You select the number of instances you want to scale different parts of your application to (there are restrictions on the max scale count in CTP1 as we are paying your bills!). And voila—the application automatically and elastically gets scaled out without any downtime!
While I can go on for a while describing all the cool and powerful things you can do with the CTP1 bits, I’ll wrap up this blog post by saying that we are super excited to share this technology preview and hope that you’ll be as excited to try them out and discover all the things we’ve built, and to take the conversation of building and managing applications to the next level! And remember, we have a limited capacity for CTP1 so sign-up quickly for your free account.
We have an exciting roadmap ahead, but we’ll get to that in future blog posts – for now, we’d love to hear what you have to say about your experience with CTP1. Watch out for a series of blog posts in the coming weeks that’ll go in to a lot more detail about the various scenarios, features and capabilities across the 3 key parts we’ve discussed today. Meanwhile, you can start with the samples that get installed with the AppFabric June CTP SDK or use the tutorials available on MSDN. You can also watch this short video on Channel 9 that Ron Jacobs and I did to give you a quick overview and demo of the things we’ve discussed above.
Welcome to a new era of building and managing rich cloud applications on Windows Azure!
Karandeep Anand for the AppFabric Team