March 01, 2011

Private vs. Public Clouds: Which is right for you?

It’s accepted that cloud computing is one of the fastest growing IT trends today. Cloud computing is a relatively simple concept whereby shared resources, software and applications are consumed by organisations ‘on-demand’ from a cloud-based service provider, much as they would consume water or electricity supplied by public utility companies. I talked about cloud’s evolution in an earlier post.

While many organisations have come to accept the notion that their IT future lies ‘in the cloud’ there is a debate raging as to the nature of cloud’s future. At the centre of this discussion is whether the cloud will be privately or publically managed.

A privately managed cloud comprises centrally managed, distributed infrastructure services that an organisation itself is able to control using technology from a service provider.

On the other hand, a publically managed cloud relies on centrally managed, distributed infrastructure services from third-party companies like Amazon and platform services from Microsoft Azure, Google and others.

Private clouds are deployments made inside an organisation’s firewall – usually from on-site data centres. Public clouds are deployments from providers who take complete responsibility for managing and securing an organisation’s entire infrastructure.

At the heart of the debate is whether the financial aspects – the billing procedures – should be inside the definition of cloud computing (as proposed by the public cloud evangelists) or whether they should be outside the definition (per the private cloud protagonists).

At issue here is whether cloud computing is seen as an operational model (public cloud) or as an evolution of existing virtualisation technologies (private cloud).

The debate is important because its resolution will have a number of significant implications for organisations – small and large – who are looking to adopt cloud computing or are currently in the process of adoption.

For example, many organisations feel public clouds are too restrictive with rigid infrastructures incapable of being customised to meet their particular needs and that private cloud technologies should be the preferred option.

Those in the public cloud camp believe private clouds represent nothing more than virtualised infrastructures with a management overlay. Moreover, they believe their (public cloud) option will prevail because of the weight of the organisations – like Amazon and Google – behind it and because they architected the utility-based billing concept on which the cloud computing concept was first based.

Before making any decision, and jumping aboard any particular bandwagon, users must address a wide range of issues, from infrastructure requirements to security and the concerns related to putting critical business data in the hands of third party service providers. Areas, such as privacy in the cloud, remain to be clarified, either by consensus or regulation.

Of course, the technology driving the cloud is still at an early stage of development and is bound to follow an evolutionary path. With this in mind, it’s best not to be blinkered. An open mind will be able to see the pitfalls of a public cloud-only philosophy which runs the risk of the environment being dominated by one or two powerful players who may well control the market.

By contrast, a private cloud-only stance will be equally restrictive and may not allow new, more beneficial technologies to evolve as quickly as they might.

Perhaps the best option is some form of federated or hybrid system delivering the best of both worlds in which the controls are provided by an in-house data centre and the low cost and flexibility benefits provided by a public cloud. Hopefully there will be a mechanism in place that will facilitate the ability to drag-and-drop applications, storage and servers between them.

Pipe dream? Not really. Industry insiders say this facility will be available to customers within 12 months.

In the mean time, the best preparation advice is to standardise data models, configurations and deployment policies for both public and private clouds. The benefits of this approach include being able to take advantage of the public cloud as soon as it is appropriate, while building a platform from which the sharing of public and private resources can be launched.

Above all, keep pace with the development of the technologies and standards that will surely come in the cloud computing space.

About The Contributor:
Martin MayRegional Director, Africa

Martin came to South Africa in 1992, relocated by Cabletron Systems to begin operations in Africa. May has driven Extreme Networks forward in Africa and is a leading advisor in the areas of infrastructure security utilizing technologies such as NAC, IDS/IPS and network-based security.

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