One of the most significant, highly anticipated, and worst kept secrets of the Windows Azure spring release is the inclusion of persistent VMs, with the notable addition of support for Linux on those VMs.
The significance of the feature is not that high architecturally — after all, Windows Azure applications that were specifically architected for Windows Azure run well already. The aspects that I find more significant are,
- Closing the gap to AWS — It is has always been difficult to compare Windows Azure and AWS because of the IaaS bias of AWS versus Windows Azure. With the addition of persistent VMs, the two platforms can be better compared and better choices made.
- Base understanding — Windows Azure is widely misunderstood, largely due to its PaaS nature. In the face of this misunderstanding, AWS as the de-facto choice, and the more common understanding of IaaS, has been easy. The addition of persistent VMs allows decision makers to go with something that is more familiar before branching out into some of the specific Windows Azure features (as customers moving to AWS tend to do).
- Not just Windows — The inclusion of Linux is a big deal for Microsoft. Regardless of Microsoft’s own reasons, having first-class support of Linux breaks the perception that Windows Azure is Windows and .NET only. Support of Java, Node.js, Ruby and now Python under Windows Azure now has more credibility with the addition of Linux to the stable.
- Architectural choices — I’ve never been a fan of running everything under the Windows Azure ‘role’ model. Running something like MongoDB or Solr in this way just seems wrong. The addition of persistent VMs now gives architects the chance to deploy technologies that work well under Linux, where there is better support and understanding of how they run. Building a solution with MongoDB running on Linux on Windows Azure is architecturally significant and very useful.
- Enterprise comfort — Enterprises with legacy applications have struggled to make the move to Windows Azure and they are probably the largest drivers of the inclusion of persistent VMs (the ‘listening to our customers’ part of Microsoft). Regardless if it is a good idea or not to run SSIS or old-school SharePoint on a cloud platform, it is something that lots of people want to do. Enterprise customers can now run whatever they like, including Linux-based parts of their solutions.
- Bring your stack — When the announcement of the spring release was made yesterday I was most interested to see the flurry of accompanying press releases. I saw news from RightScale, Cloudant, Opscode and 10Gen. These, and similar, organisations are the backbone of the cloud community and their support of Windows Azure (however extensive it may be) greatly increases the reach of Windows Azure into areas of the cloud playground where the cool kids are hanging out.
It will be interesting to see, over the coming weeks, how the markets and the clouderati respond to these announcements. It was a move that Microsoft had to make and they need to get the right messages about the changes out to the market in order to gain better traction of Windows Azure.