When (Micro)Seconds Matter
In cloud computing environments the clock literally starts ticking the moment an application instance is launched. How long should that take?
The term “on-demand” implies right now. In the past, we used the term “real-time” even though what we really meant in most cases was “near time”, or “almost real-time”. The term “elastic” associated with scalability in cloud computing definitions implies on-demand. One would think, then, that this means that spinning up a new instance of an application with the intent to scale a cloud-deployed application to increase capacity would be a fairly quick-executing task.
That doesn’t seem to be the case, however.
Dealing with unexpected load is now nothing more than a 10 minute exercise in easy, seamlessly integrating both cloud and data center services.
-- Cloud computing, load balancing, and extending the data center into a cloud, The Server Room
A Twitter straw poll on this subject (completely unscientific) indicated an expectation that this process should (and for many does) take approximately two minutes in many cloud environments. Minutes, not seconds. Granted, even that is still a huge improvement over the time it’s taken in the past. Even if the underlying hardware resources are available there’s still all of the organizational IT processes that need to be walked through – requests, approvals, allocation, deployment, testing, and finally the actual act of integrating the application with its supporting network and application delivery network infrastructure. It’s a time-consuming process and is one of the reasons for all the predictions of business users avoiding IT to deploy applications in “the cloud.”
IT capacity planning strategy has been to anticipate the need for additional capacity early enough that the resources are available when the need arises. This has typically resulted in over-provisioning, because it’s based on the anticipation of need, not actual demand. It’s based on historical trends that, while likely accurate, may over or under-estimate the amount of capacity required to meet historical spikes in demand.