Public Clouds vs. Private Clouds

What are public clouds?

Public clouds consist of shared IT resources, such as computing power (servers), networking services, and data storage. Public clouds are the most common type of cloud, and references in the IT world to “the cloud” usually mean a public cloud.

With public clouds, resources are managed by a third party, known as a cloud hosting provider.

Cloud hosting providers include Amazon Web Services, Microsoft Azure, Google Cloud, and Oracle Cloud.

With public clouds:

IT hardware costs can be avoided

Companies that use public cloud technology do not have to invest in IT hardware such as servers and networking equipment. Further, companies using public clouds do not have to spend substantial amounts of money building out data centers in which to operate the IT hardware.

Infrastructure maintenance is outsourced

With public clouds, companies do not have to maintain their own IT hardware infrastructure. Maintenance is outsourced to a cloud hosting provider. The cloud hosting provider ensures that all of the cloud resources remain available to the company.

Resources can be scaled up or down on demand

Public cloud resources can be scaled up or down as needed by a company.

When additional computing capacity is needed, servers can simply be “spun up” on the cloud hosting provider. When the computing capacity is no longer needed, the servers can be spun down.

With public clouds, companies pay only for the resources that they are actually using.

Reliability can be guaranteed

Public clouds are operated on enterprise-grade IT hardware located in data centers all over the globe. Geographical distribution helps to eliminate single points of failure, ensuring high levels of availability of cloud resources. In fact, most larger public cloud hosting providers offer guaranteed service level agreements, or SLAs.

What are private clouds?

Complementary to public cloud technology is private cloud technology.

Unlike public clouds, private clouds consist of IT resources that are under the exclusive control of the company operating the private cloud. The IT resources are not shared.

Private clouds are operated on company-owned IT hardware located on company premises, or in data centers contracted to host the company IT hardware.

Private clouds offer:

Great flexibility over hardware and software configurations

Companies that want to be able to fine tune their cloud for their specific needs choose private clouds over public clouds. Compared to public cloud technology, private cloud technology gives companies great flexibility over hardware and software configurations.

Sole control over company data

Private clouds allow companies to retain sole control over their data. This means that companies know exactly how their data is being duplicated and replicated. They know exactly how backups are being made and where the backups are being stored.

Further, the sole control companies exercise over their data in a private cloud helps to ensure the data remains private.

Distributed and scalable resources

Similar to public clouds, private clouds allow IT resources to be distributed and scaled.

With private cloud technology, IT infrastructure that has already been built by a company can be distributed and scaled in a manner appropriate for the needs of the company.

What are the differences between public and private clouds?

The primary differences between public and private clouds are:

  1. Who maintains the cloud IT hardware
  2. Who controls the company data

Maintenance of IT hardware

An important distinction between public and private cloud technology is that with public cloud technology, the IT hardware on which the cloud operates is maintained by the cloud hosting provider.

The downside of having a cloud hosting provider maintain the IT hardware is that it can come at a substantial financial cost, factored into the price charged by the cloud hosting provider.

Further, companies using a public cloud do not have input into the choice of hardware being used to operate the cloud, as they would with a private cloud.

Control over company data

When using a public cloud, company data is in the hands of the cloud hosting provider. The cloud hosting provider is responsible for the safeguarding of the data.

Should there arise some security vulnerability that allows another “tenant” company on the public cloud to access data belonging to other cloud tenants, company data could theoretically be compromised.

Since private clouds are entirely controlled by the company that owns the cloud, there is no risk of another cloud tenant being able to access private company data.

Which is better: public cloud or private cloud?

It is impossible to say that a public cloud is better than a private cloud, or that a private cloud is better than a public cloud. The answer is different for each individual company.

Companies that operate primarily on the Internet, such as online retailers, probably would benefit the most from using a public cloud. Online retailers often do not make good use of the granular configuration that private cloud technology allows. Further, much of the data used and generated by online retailers is not confidential in nature and is sufficiently protected by the security built into public clouds.

On the other hand: companies that work with highly sensitive data, such as companies in the healthcare industry or finance industry, probably would benefit the most from using a private cloud. In fact, some regulations might, due to privacy concerns, prohibit data from being stored in a public cloud.