Microsoft's Azure cloud platform: A guide for the perplexed

Now that the initial Microsoft PDC pixie dust has settled, developers are trying to digest exactly what Microsoft's cloud platform is. Here's my attempt to explain it.
Written by Mary Jo Foley, Senior Contributing Editor

Now that the initial Microsoft PDC pixie dust has settled, developers are trying to digest exactly what Microsoft's cloud platform is. Here's my attempt to explain it.

Microsoft layed out its "Azure" foundational infrastructure for the cloud during the keynote kick-off on day one of the Professional Developers Conference (PDC) here in Los Angeles. The goal of Azure is to provide developers who want to write applications that run partially and/or entirely in a remote datacenter with a platform and set of tools.

Microsoft did not disclose pricing, licensing or timing details for Azure. The company is planning to release a Community Technology Preview (CTP) test build of Azure to PDC attendees on October 27. (The CTP consists of a software development kit and access to Microsoft's cloud.

This is what Microsoft's cloud looks like, from an architectural diagram standpoint:

Layer zero (which is not on this slide) is Microsoft's Global Foundational Services. GFS is like the hardware abstractionlayer (HAL) in Windows. It is the lowest level of the software that interfaces directly with the servers.

Layer one is the base Azure operating system. This is what used to be codenamed "Red Dog." Red Dog was designed by a team of operating-system experts at Microsoft, led by Amitabh Srivastava, Corporate Vice President of Cloud Infrastructure Services. Dave Cutler, the guy who is credited as the father of VMS and Windows NT, was one of the lead developers on Red Dog. (I asked Srivastava what Cutler's role was with Red Dog and he said he focused heavily on how the hypervisor/virtualization technology could be made to scale across datacenter servers.)

Red Dog is what networks and manages the set of Windows Server 2008 machines that comprise the Microsoft-hosted cloud. At the highest level, Red Dog consists of four "pillars": Storage (like a file system); the "fabric controller," which is a management system for modeling/deploying and provisioning; virtualized computation/VM; and a development environment, which allows developers to emulate Red Dog on their desktosp and plug in Visual Studio, Eclipse or other tools to write cloud apps against it. The way Red Dog is architected is Microsoft only has to deploy Red Dog on a single machine and then multiple instances of it can be duplicated on the rest of the servers in the cloud using virtualization technology, Srivastava said.

"We do Xcopy to deploy on every machine. Each machine has its own cache," Srivastava explained.

Layer two is the set of building block services that run on top of Azure. Developers are not required to use these services and will be able to mix and match among them. The initial set of services include Live Services (a k a the Live Mesh platform); SQL Server Data Services (now known as SQL Services); .Net Services (formerly known as "Zurich"); SharePoint Services and Dynamics CRM Services. Developers will be able to build on top of these lower-level services when constructing cloud apps. SharePoint Services and CRM Services are not the same as SharePoint Online and CRM Online; they are just the platform "guts" that don't include user-interface elements.

(Another clarification: Layers one and two together -- the thing Microsoft calls the "Azure platform" -- is what was briefly known as "Windows Strata.")

Layer three are the Azure-hosted applications. Some of these are from Microsoft and include SharePoint Online, Exchange Online, Dynamics CRM Online. Others will be authored by third-party developers.

Over time, Microsoft is promising some bigger things from its cloud platform. First, the company has committed to delivering Microsoft-hosted versions of all its enterprise apps. So those rumors of Forefront Online and System Center Online that I'v been hearing about for months sound like they are on the drawing board. These Online services -- as well as all of Microsoft's Live services -- are being slowly moved to run on top of Azure. (Right now, the only Microsoft Live property hosted on Azure is Live Mesh. The next one that will be is Live Meeting, Srivastava said.)

So besides the obvious -- licensing, pricing and due date -- what else do you want to know about Microsoft's cloud infrastructure? Any holes you see so far?

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