Tuesday, October 03, 2006

Service Virtualization defined

The biggest issue I've had with server virtualization vendors has nothing to do with the applicability of their products. I believe firmly that hardware virtualization is key to truly optimizing capacity usage and costs in a datacenter environment. No, the problem I have is with the rather insane notion that solving your hardware utilization problems solves your IT problems. In other words, as long as you can manipulate servers, your costs will be minimized and compliance with service levels will be a no brainer.

That's crazy.

My argument starts with the observation that its not server utilization service levels that businesses care about, but the quality and availability of the services that run the business that really matter. From a business perspective--from the view of the CEO and CFO--its not how many servers you use and how you use them, its how many orders you gather and how cheaply you gather them.

So, this focus by the VM companies on hardware and manipulating servers (virtual or not) falls short of meeting the goals of the business. Look closely at what VMWare, Virtual Iron and even XenSource are offering:
  • Virtual Servers. This is the core of their value proposition, and its by far the most valuable tool they deliver. As we established earlier, this is needed technology.
  • Virtual Server Management. VirtualCenter, Virtualization Manager, etc. provide key tools for managing virtual servers.
  • Automation. Tools to provision, expand, move and replace servers based on current observed conditions.
What's missing from all this? I'll give you a hint: where's the word "service" above?

Virtual machine technologies have no concept of a service, or even an application. They barely have the concept of an OS. This is by design; if they focus on the hardware virtualization problem, they have a fairly simply bounded problem--just make some software behave exactly like its emulated hardware platform. That way, you can cover existing software installations with minimal effort, and don't have to worry about the vagrancies of application, network and storage configuration. All of that can happen outside of a simple virtualization wrapper targeted at making the virtual servers work in the physical reality.

The true holy grail for IT, in my opinion, is service virtualization. I will define service virtualization as technology that decouples a set of functionality (a web service, an application, etc.) from any of the computing resources required to execute that functionality, regardless of whether those resources are themselves hardware or software. What we ultimately want to do is to optimize the delivery of this functionality by whatever metric is deemed important by the business.

Thus, I applaud the validation of policy-based automation, decoupling of physical hardware from software and automated response to server load and failure that the VM companies are clearly giving. However, I caution each of you to consider closely whether automating server management is enough, or if service virtualization is the better path.

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