Cloud Computing, VDI and the future of Desktops-as-a-Service

Contributed Article by Amir Husain, President & CEO, VDIworks

One of the more popular questions today's IT directors and systems administrators are faced with is whether the advent of cloud computing means that desktop virtualization is no longer relevant. On the surface, this seems to be a perfectly credible question. After all, the Cloud, as an IT meme, emerged after VDI had already been written about and discussed in the IT press for a year or two. Does the Cloud really represent an alternate architecture separate and de-linked from virtualization in general and VDI (Virtual Desktop Infrastructure) in particular? As it turns out, the answer is, "Not really!". Looking at Cloud computing as an alternate to VDI is ignoring the reality that cloud computing has, as its essential underpinning, an enabling layer made possible by virtualization. The Cloud, as a delivery paradigm, is not so much an alternative to virtualization or even VDI, as it is an overarching architecture that makes use of hypervisors and the underlying functionality they enable. 

Future desktop architectures have a variety of attributes in common. For example, the ability to separate the system image (OS, apps etc.) from the underlying hardware, the ability to implement disaster recover, high availability, mobility and remote access, the kind of endpoint security that is offered by a centralized architecture, and of course, ease of management that extends not only to the system image and the applications installed but also to the user data itself. What is essential is the provision of these capabilities and of secondary importance is how they are delivered and what specific infrastructure is used to enable this delivery. Virtualization brings together many of the capabilities we will expect from future desktops. And when delivered over the cloud, these capabilities will be combined with mobility, ubiquitous access and a platform independence that will, for example, allow emerging, lightweight ARM-based tablets to access powerhouse x86 applications and vice-versa.

There is little doubt that Cloud computing is the hottest IT topic these days. A simple Google query tells us that over 87 million references to the term are found on the web. But despite the ethereal connotations it conjures, just like any other IT system or architecture, the Cloud too is built with tangible, physical components: Servers, operating systems, virtualization software and management applications. Of course, this plethora of capabilities is delivered across the Internet from a data center that the end-user may be entirely oblivious to, or across networks which are not managed or owned by the enterprise consuming the experience enabled through the cloud. In short, while the enablement and delivery process enabled from a backend datacenter may be obfuscated from the consumer of the experience, the very fabric of the Cloud is built atop virtualization. When it comes to efficient utilization of multicore CPUs and ever-increasing server capacities virtualization is an incredibly important tool that allows these resources to be tapped and managed effectively. And perhaps even more importantly, by creating standardized x86 containers, or VMs, Hypervisors allow highly multicore CPUs that could not be tapped effectively by a single application, to now run dozens of single-threaded or modestly parallelized applications on the same CPU. This containerization is at the heart of datacenter density; the very quality that makes large Cloud infrastructure economically viable and practical.

Leveraging virtualization in this fashion, an increasing number of data center companies and MSPs are providing hosted Cloud capabilities over public networks. Systems integrators and IT shops offer private Cloud installation and configuration services. Companies like Amazon and Rackspace are thought leaders in the public Cloud category, and they are also poster children for the Xen Hypervisor. The OpenStack initiative provides a collection of management tools and software necessary to deploy public or private clouds. There is real, tangible momentum behind Cloud deployments. And now this momentum is being translated not just to online backup, server app hosting and scaling, but also to desktops in the Cloud.

Cloud hosted desktops, or Desktops as a Service (DaaS) have been offered by numerous vendors in many different ways and in myriad manifestations. The first model dates all the way back to the late '90s when a company called desktop.com launched a browser-based operating system written in JavaScript, complete with its own API and designed to replace conventional operating systems. This was an era when Larry Ellison, Marc Andressen and Scott McNealy were aggressively pushing the NC, a Network Computer that would be svelte "appliance" computer tapping into large Sun servers, rendering applications using the Netscape browser. It was then that Sun had proclaimed, "The Network is the Computer". While the NC did not take off, and neither did Netscape replace Windows as an operating system alternative, the notion of having a lightweight, inexpensive client device tap into an OS and apps running across the network has been revisited on numerous occasions since. It is an idea that is reborn every few years, waiting for its time to come.

Technology has matured immensely since the days of Desktop.com, and today, advances in JavaScript technology, HTML 5, browser process isolation, stability and new security models make this vision somewhat more viable. But it is still far from replacing a conventional desktop. There have been a variety of brave attempts to showcase what is possible with this architecture, for example jolicloud and G.ho.st. A second model, one that's being advocated by Google, seeks to make the browser the operating system rather than running a JavaScript "OS" inside a browser. The Chromium initiative is exactly that. While the reality is that Chromium requires an underlying, bare-bones operating system to function, these details are hidden from the user and ultimately the user sees the Chromium browser interface as the equivalent of the erstwhile desktop. While having Google as a backer can't hurt, and partnerships with Samsung and other netbook manufacturers have assisted distribution, this model too is yet to see serious adoption. This brings us to the third network-delivered desktop model, one that is closest to the desktop experience delivered by PCs today; the hosted VDI model. Here, we essentially have Linux or Windows virtual machines hosted on servers in the cloud made accessible to users over a wide area network. While all the management, high-availability, security and hardware independence benefits inherent in virtualization are available with this model, what makes it most palatable for end-users is the familiar desktop paradigm, applications and the conventional operating system they get access to. With HTML 5 and other advances in browser-based technology things may change in future but for now the most viable way to deliver a practical, usable cloud hosted desktop is most certainly via hosted VDI. 

What will be interesting to see is how future developments in Operating System technology and the fusion of gestures and touch interfaces impacts the viability of various network-delivered desktop models. Windows 8, for example, will provide native execution on ARM, but most legacy Windows applications will not function on this processor architecture, instead requiring x86 processors. This incompatibility promises to create opportunities for users and vendors to leverage a hosted VDI model to deliver legacy execution environments to inexpensive Thinclients, tablets and ultra-compact laptops based on ARM processors. The other two models we discussed, a Chromium style browser OS and an HTML 5 based in-browser desktop, try to essentially replace a local OS. It is not clear that this is the most effective strategy to deliver the rich device interaction and user interaction desktop computing seems to be headed toward. Windows 8 is actually focusing on the addition of touch-based interactivity, gestural interaction, vision based gesture recognition and speech interfaces. To process this rich set of inputs, the OS on the client will need to have native components that go beyond the capability of a browser, and require more native access to hardware than what HTML 5 can provide. It would make sense, then, to run the user interaction layer on the local device and perform as much computation on a cloud hosted virtual machine, as possible. Windows 8 - it is is widely adopted and seen as a success on non-x86 devices - may provide the hosted VDI model with massive impetus that results in large scale adoption of Cloud hosted desktop virtualization. Whichever direction desktop infrastructure technology takes, what is abundantly clear is that desktop virtualization; Cloud leverage and non-x86 architectures will be playing a major role.

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