Cloud computing - public und private cloud

Question

I'm trying to understand the difference between public and private cloud. I think it's like this: Public Cloud = My service is in a public environment, hosted on a server of a company Private Cloud = I'm setting up my own cloud with my own hardware

Is this correct? I'm really confused by all the explanations i found on the web.

Answer 1

The public cloud consists of a service or services that are purchased by a business or organization and delivered via the Internet by a third-party provider. These services use storage capacity and processor power that is not owned by the business itself.

A private cloud is essentially an extension of an enterprise's traditional data center that is optimized to provide storage capacity and processor power for a variety of functions. "Private” refers more to the fact that this type of platform is a non-shared resource than to any security advantage. More good reading on the same topic: https://www.stratoscale.com/blog/cloud/private-cloud-vs-public-hybrid-or-multi/

Answer 2

You got it right, basically. Private clouds are indeed meant frequently for larger organizations, those who are capable and in need of having their own cloud server, being independent and apart of any other company's cloud (it has many further consequences on security and availability of the cloud and services given). Public cloud users have the same underlying infrastructure as they use the cloud.

Large organizations like to occupy private clouds, simply because they're the only 'user' using this specific underlying hardware as well as virtual machines and services that run on it. Another thing that's been getting popular lately, is a hybrid cloud (such as Stratoscale, for example), which is basically a private cloud programmed according to the client's needs, but with the ability to use components drawn from public clouds. this gives the client a much bigger flexibility regrading data deployment.

Answer 3

Today there are multiple public cloud service providers and private cloud solutions. bellow posts shows comparison between top 5 CSP and private cloud solutions.

Private cloud comparison: http://www.cloudometry.in/2015/07/private-cloud-adoption-and-leadership.html

Public Cloud service provider: http://www.cloudometry.in/2016/03/cloud-service-provider-comparison-2016.html

Answer 4

You should be aware about software You will use as a base of Your cloud - both public and private. In example, if You will develop Your solution in public cloud You must remember that not allways it will be possible to migrate to Your private cloud with no refactoring Your app. So if You develop, let say, in Amazon cloud, You are locked to public cloud or some compatibility middleware in private cloud - it is because Amazon is public-only cloud and You have no option to run "private Amazon". Same in Google. In other hand, if You will develop in Microsoft Azure public cloud, You can build Your own Azure Private Cloud in future (it calls Azure Pack) and migrate solution. Of course there is few Open Source cloud platform You can use to build You own private cloud - such as OpenStack or CloudStack. The question is if You find public cloud based on exactly the same stack with migration warranty... I don't know... OpenStack is very popular as private cloud solution and we have few public cloud based on it but it is also very uncommon environment - in example one provider uses some storage mechanisms and other will use some different - both uses OpenStack as a base.

Answer 5

Yes, public cloud is a shared environment, but private cloud not necessarily means you need to use your own hardware. Private cloud is a dedicated environment, either hosted in the organization's own data center (on-premise) or by an external cloud computing provider. Private just refers to the fact that this type of platform is a non-shared resource. You can find a good description here:

Public Clouds

Public clouds are owned and operated by third-party service providers. Customers benefit from economies of scale because infrastructure costs are spread across all users, thus allowing each individual client to operate on a low-cost, “pay-as-you-go” model. Another advantage of public cloud infrastructures is that they are typically larger in scale than an in-house enterprise cloud, which provides clients with seamless, on-demand scalability.

It is also important to note that all customers on public clouds share the same infrastructure pool with limited configurations, security protections and availability variances, as these factors are wholly managed and supported by the service provider.

Private Cloud

Private clouds are those that are built exclusively for an individual enterprise. They allow the firm to host applications in the cloud, while addressing concerns regarding data security and control, which is often lacking in a public cloud environment. There are two variations of private clouds:

• On-Premise Private Cloud: This format, also known as an “internal cloud,” is hosted within an organization’s own data center. It provides a more standardized process and protection, but is often limited in size and scalability. Also, a firm’s IT department would incur the capital and operational costs for the physical resources with this model. On-premise private clouds are best used for applications that require complete control and configurability of the infrastructure and security.

• Externally-Hosted Private Cloud: This private cloud model is hosted by an external cloud computing provider (such as Eze Castle Integration). The service provider facilitates an exclusive cloud environment with full guarantee of privacy. This format is recommended for organizations that prefer not to use a public cloud infrastructure due to the risks associated with the sharing of physical resources.