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99 problems but the cloud ain’t one: What's the difference between private, public and hybrid clouds?

Cloud computing is one of the most important technologies in the world right now, but it can be extremely confusing at times. This series aims to take the jargon out of the cloud and explain things in a much more brain-friendly way.

Cloud computing has brought about a paradigm shift in the field of information technology. It is probably the most talked about trend in the IT sector and it is the industry buzzword. The reason is simple – cloud offers many advantages, including reduced capital expenditure, increased flexibility, scalability, ease of access to information, instant provisioning and speedy deployment.

Cloud computing is available in three forms: private, public and hybrid. As the three variants are discussed further down the page, it will become clear that the best option for each client is based primarily around the how critical their application, control and security requirements are. Compliance needs and the extent to which the applications are integrated with enterprise functions are also important to consider.

Cloud computing is increasingly gaining momentum as the technology of choice for businesses. Read on to discover the differences between the three separate models.

Private cloud

A private cloud primarily caters to the IT needs of one organisation using a private network and offers a highly secure environment. It can be managed internally, externally by an internal IT team, or by a solution provider. A private cloud implementation does not have to be local or in-house; it can be located outside the company premises in a single or in multiple locations, so there may be dedicated servers in different locations, and this could still be classified as a private cloud configuration, due to the restricted access of cloud resources.

The information held in a private cloud is protected behind a firewall that is accessible to users with appropriate access rights and only available for employees (or agents) of that organisation. This makes it highly secure and redundant. The data in the private cloud stays within a specified data centre, making integration with other systems much simpler. This deployment model offers the highest level of security and control, which makes it less economical compared to other cloud options.

Private cloud examples: OpenStack, CloudStack, VMware

Public cloud

A public cloud is owned by a service provider, offering the highest level of efficiency through the use of shared resources. These are often owned and operated by third-party service providers that provide anything from simple storage services to complex solutions around infrastructure and application services. In this deployment model, the computing infrastructure and resources are shared between multiple organisations and customers. Since the public cloud works on a shared model, where the cost of infrastructure is spread out amongst a number of users and organisations, this provides a cost advantage to customers and is hence a more cost-effective option to the private cloud.

Public cloud services may be free or offered on a pay-per-usage model. The benefits of the public cloud model include easy onboarding, since the infrastructure is already available from the service provider, cost-effectiveness, since the hardware, OS and application costs are covered by the provider. Uptime is often provided with 24/7 support and delivered with on-demand scalability.

Public cloud examples: NaviSite Managed Cloud Services, Amazon Elastic Compute Cloud (EC2), Google Compute Engine, HP Cloud Services, Microsoft Azure Services Platform

Hybrid cloud

This model is a combination of public and private clouds, whereby specific resources are used in a public model, while others are used in a private one, providing increased efficiencies. Clearly public and private cloud options have their pros and cons as mentioned above, so when selecting a particular deployment for a specific business, there is a high possibility that any organisation will differ in their implementation of public or private cloud models, based on application integration and security-related concerns. There is no one single option which can be considered a perfect fit for all customers looking to migrate to the cloud.

Read more: Public, private, hybrid: Which cloud is best for your business?

The public cloud has its cost advantage and offers scalability, while the private cloud provides security and flexibility – each with their respective trade-offs. Combining the two in the form of a hybrid cloud offers customers the advantages of both deployment models, allowing an organisation to choose a public cloud implementation for some of its applications and a private cloud for others. This hybrid model has been gaining acceptance and is becoming increasingly popular because of the flexibility it offers.

by Vivek Vahie, senior director at Navisite India, you can hit him up via his LinkedIn profile

For more cloud jargon busting check out the rest of our "99 Problems but the cloud ain't one series:

Vivek Vahie
Vivek Vahie is a Senior Director of Service Delivery at Navisite. He has over 20 years of experience in IT infrastructure, application management and professional services.