Author Topic: Cloud Deployment Models: Public & Private  (Read 596 times)

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Cloud Deployment Models: Public & Private
« on: June 25, 2015, 10:25:16 AM »

The cloud hosting described up until have been examples of public cloud hosting. The ISO definition of public cloud is:

Public cloud:
“Cloud deployment model where cloud services are potentially available to any cloud service customer and resources are controlled by the cloud service provider. A public cloud may be owned, managed, and operated by a business, academic, or government organization, or some combination of them. It exists on the premises of the cloud service provider. Actual availability for specific cloud service customers may be subject to jurisdictional regulations. Public clouds have very broad boundaries, where cloud service customer access to public cloud services has few, if any, restrictions.”

Put simply, a public cloud is cloud IaaS managed by a cloud service provider (examples: Datasoft, Internap, Rackspace, Amazon AWS, Google Cloud Platform) and available to pretty much anyone, usually with the features described above, and sometimes with a PaaS option.

A private cloud uses the same cloud computing techniques and offers the same features as the public cloud, except that the underlying pool of computing and storage resources is controlled and exclusively available to the customer. This infrastructure may be hosted by the customer (on-premises), or hosted by a hosting provider (off-premises). The latter is sometimes referred to as a ‘hosted private cloud’.

The ISO definition of private cloud is:

Private cloud:
“Cloud deployment model where cloud services are used exclusively by a single cloud service customer and resources are controlled by that cloud service customer. A private cloud may be owned, managed, and operated by the organization itself or a third party and may exist on premises or off premises. The cloud service customer may also authorize access to other parties for its benefit. Private clouds seek to set a narrowly controlled boundary around the private cloud based on limiting the customers to a single organization.”

Private cloud provides additional control, ‘privacy’ and an alternative cost model. With private cloud, the customer pays a fixed price for the underlying infrastructure plus any software licensing. For customers who value the flexible and responsive features of cloud hosting and the fixed-cost model of dedicated hosting, this is an interesting choice. It also offers the opportunity for large organizations to allocate costs within their organizations by charging It resources to internal customers on a pay-per-use model.

Another big benefit of private cloud is the ability to apply the additional control and benefits of cloud computing to existing data center operations. As the manager of the private cloud, a customer has access to a global view of their infrastructure. This allows the customer to monitor their infrastructure, apply templating, and automate operations – things like automatically scaling VMs in response to an applications needs.

Public clouds offer a relatively simple way to access the scalability and pay-per-use benefits of cloud computing. Private clouds offer a compromise between public cloud scalability and private infrastructure control and fixed costs. Private cloud is a more involved choice, and often a ‘bigger solution’ but offers many additional operational benefits when compared to more traditional dedicated hosting.