Cloud Computing Comparison: PaaS Providers

Microsoft's move to add infrastructure and enhanced virtual machine support to its Azure platform gives its cloud offering the ability to match Amazon's infrastructure-as-a-service (IaaS) product while still providing customers with richer platform-as-a-service (PaaS) options, according to one analyst who believes Microsoft is well positioned to gain cloud momentum in 2013.

"We remain positive on Azure, due to its high compatibility with existing enterprise software," said Mark Moerdler, senior software analyst at Bernstein Research, in a note published Wednesday.

Microsoft last year launched a Community Technology Preview of persistent-state Virtual Machine support for Azure, effectively creating a hypervisor in the sky that lets enterprises upload VMs running Linux, SharePoint, SQL Server or other "stateful" applications. The move expanded the capabilities of Azure, which Microsoft had always positioned as a PaaS offering, into the IaaS realm.

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Under the PaaS model, customers' apps and services run on a cloud stack that's preconfigured by the vendor, while IaaS provides customers with basic infrastructure, on top of which they can build their own stacks and services while maintaining more management responsibility over the setup.

Moerdler said in an interview that Microsoft is now able to offer customers the best of both worlds, which could entice more enterprises to its cloud services. "With Azure, they can run VMs, but they can do more than that, in that they can allow you to be able to step up to a more cloud-based solution," said Moerdler.

Moerdler defines a truly cloud-based solution as one that uses a multi-tenant architecture. The difference between multi-tenant and simple virtualization is, generally, that in the former scenario a single instance of an application services multiple clients, while in the latter multiple instances of an app are run across virtual machines. Multi-tenant architectures are thought by many experts to be more robust and scalable than virtualized setups.

Azure "is competing against Amazon Web Services in Infrastructure-as-a-Service in terms of virtualization, but they give you this opportunity of saying you can go and become a truly cloud-based model if you so desire," said Moerdler, who rates Microsoft shares as "Outperform".

Moerdler believes Azure also holds another, potentially significant advantage over AWS, as well as over competing PaaS providers such as Oracle and Salesforce's Heroku -- its native compatibility with Microsoft's on-premises products like Windows Server 2012 and SQL Server. That should, theoretically at least, make it easier for Microsoft-centric enterprises to move operations to the cloud when they so choose.

"Most apps can be moved to Azure fairly easily initially in a VM and then expanded, adding cloud functionality later," said Moerdler, who co-founded records management specialist MDY Advanced Technologies prior to joining Bernstein.

Microsoft hosts Azure at eight, company-owned data centers located around the world. To further bolster its cloud, Microsoft in December added job scheduler support for Windows Azure Mobile Services, improved scaling for Azure website services and support for SQL Data Sync Services from within the Azure Management Portal.

More Azure rollouts are expected throughout 2013.