If you are an infrastructure service provider and partner of Microsoft you probably haven't been too pleased with the Redmond horde of late. Are they friend or foe? Sure, you can resell and host Windows Server and a plethora of Microsoft applications from your data centers. And if you're ambitious you can even use their Dynamic Infrastructure Toolkit to build your own infrastructure-as-a-service (IaaS) cloud. But Microsoft's own online services for the enterprise are off limits. Business Productivity Online Suite (BPOS), Windows Azure, and SQL Azure are offerings that look a lot like a formidable competitor. Well partner centricity now rules the day when it comes to Azure.

At its Worldwide Partner Conference in Washington, D.C. today, Microsoft announced the Windows Azure platform appliance program that will let large service providers (and very large enterprises) bring this PaaS platform (plus SQL Azure)  into their own data centers. This move is powerful for both Redmond and its service provider partners.

For managed service providers (MSPs) like HP, Fujitsu, and Dell Cloud Services, Windows Azure platform appliance provides fast go-to-market for a differentiated cloud service — it's PaaS for .Net and Java (and myriad other languages) today; it will add IaaS late this year. Microsoft will manage the cloud layer but not own the infrastructure, the customer, or the customer interface. Hosting companies will be free to package the service any way they see fit, including walling it off as a hosted private cloud that is fully disconnected from the Microsoft Windows Azure service. Want to deploy a service in hybrid mode — part on Azure part on traditional hosting — without intraservice latencies? A hosting provider will be able to offer that.

Microsoft gets to proliferate Windows Azure to more geographies, data centers, and users than it could purely on its own. Want Azure in Uzbekistan to ensure citizen data doesn't leave that country? You got it, as ISPs can now offer Azure themselves. That's an investment Microsoft itself probably couldn't justify.

For enterprise and government infrastructure & operations professionals this announcement brings greater degrees of freedom in using Windows Azure but won't bring Azure in-house for more than the few very largest companies…at least not yet. The reason is purely technical. Windows Azure is designed to run on thousands of nodes at a time. Its core value is survivability of node failures and you need to have a significant number of nodes beneath it. So how few nodes is too few? That's to be determined. As a result, Microsoft is smartly taking a conservative approach by only releasing Azure platform appliance to very large customers like eBay, initially setting the lower limit at 1,000 servers. If you fit this bill, Dell, HP and Fujitsu will be more than happy to help you set it up in your data center. 

It should also be noted that Windows Azure, unlike Windows Server, isn't certified to run on a wide swath of servers or configurations. So partners that want to deploy it will have to agree to a specific set of component and configuration guidelines. This will make Windows Azure platform appliance a challenge for many hosting companies and enterprises to deploy. It will also give a time-to-market advantage to those who jump on this first.

The key question for Forrester clients is whether this makes Windows Azure a more appealing cloud platform. PaaS offerings have seen lower enterprise interest and adoption thus far due to concerns about lock-in. Windows Azure isn't immune to this as there are unique APIs for leveraging this platform. But if you are a .Net shop or develop in .Net and Java and deploy to Windows Server, then you'll find what you are looking for here. Yes, it is possible to build an app for Azure and move it back and forth between the PaaS platform and Windows Server 2008. The real question is what do you want out of the Azure platform? If you simply want to test the functionality of an application destined for Windows Server 2008 in your own data center and are just looking for faster access to resources for this type of testing, Azure fits the bill. But more likely you want to run the application on Azure because you want to take advantage of its automatic scalability. For that, you have to write to its APIs. And you should. 

There's no such thing as open scalability across cloud platforms. If you want autoscaling you will have to write to (or leverage through other means) the proprietary APIs of any cloud platform — Amazon Web Service' EC2 included. 

The second and frankly more common objection to Azure is that it is a public cloud and simply by being such raises the hairs on the back of your CSO's neck. Our advice to Forrester clients is to get over this concern and realize that security in the cloud is not missing, it's just a different animal and you have to adapt your security practices to the cloud; don't expect clouds to adapt to you. But if you still won't use it, now Microsoft has the means of delivering Windows Azure in a closed-off fashion, which will hold strong appeal to enterprises with these worries, given the limitations noted above (1,000 nodes). 

Should you add Windows Azure to your short list of cloud candidates now, if you didn't before? It's certainly worth a second look once these new deployments take place. 

Attending Microsoft WPC? Come to my presentation on how you can help customers transition to the cloud and achieve greater profitability. 1:30-2pm in the Live Theater in the WPC Expo Hall. 

– John Rymer contributed to this report.