What is the Relationship Between Cloud and Virtualisation?

With tightened budgets, businesses are constantly looking for way to see a rapid return on investment (ROI). This has increased interest in the adoption of pay-as-you-go cloud services and virtualisation technologies where the ROI can be very attractive.

In recent months, Tom Brand, virtualisation practice lead at GlassHouse Technologies (UK) has found himself frequently answering the question: “What is the difference between cloud computing and virtualisation?” In Tom’s latest blog post he gives his view...

In order to answer this question it is first important to clarify what the two terms, cloud computing and virtualisation, actually mean:

According to the National Institute of Standards and Technology (NIST), cloud computing is a pay-per-use model for enabling available, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.

Virtualisation is a technique used to abstract the physical characteristics of computing resources from the systems, applications or end users that interact with those resources.

Virtualisation technologies typically let a single resource (such as a server, an operating system, an application, or storage device) appear as multiple logical resources; or makes multiple physical resources (such as storage devices or servers) appear as a single logical resource.

In analysing the definitions above, trying to compare cloud computing and virtualisation is similar to comparing a car to an engine respectively.

A car is a complex system including parts, interfaces, inputs and an engine that function as one to provide the best and most efficient drive for the owner.

Like the car, cloud computing (public or private) is essentially the coming together of technologies, operational processes and financial models to provide organisational flexibility with optimum cost-efficiency.

Continuing with the automotive analogy, the engine of a car is a core component because without the engine, the car won’t move, regardless of whether there are any seats in it.

With cloud computing, virtualisation is the core component enabling the majority of characteristics required to make any cloud computing model work.

Going one stage further, you can compare the cloud to a cost-effective metered taxi service, always at your disposal. You now have a range of highly efficient vehicles that can be requested whenever you need to travel.

They are operated and maintained by someone else and you only pay for the length of the journey (paying-as-you-go) with the ability to get out whenever you like.

Although cloud computing encompasses a large range of compute services, typically labelled as either infrastructure (IaaS) or applications (SaaS and PaaS), they all fit within the taxi model.

End users only pay for the services or resources they use, the service and ability to provision is always available. Users have the flexibility to request different services however the underlying infrastructure is not their concern and cannot be modified.

In summary, virtualisation improves IT efficiency - enabling traditional computing with fewer resources; whereas cloud computing improves IT effectiveness - empowering more people to build services with more flexibility and fewer experts. When implemented accurately, both technologies can provide attractive an ROI for the IT department.