Cloud Delivery Models
You have just learned about the different service models available for implementing
a cloud computing solution. In order to realize the value from these service models and
for the customers to have access to them, a delivery model must be chosen. Implementing
a cloud deployment model can vastly impact an organization. Implementation requires
careful consideration and planning in order to be successful. If your role is the IT
administrator, it is your responsibility to educate the organization on the benefits
and challenges of implementing a cloud computing model. You need to evaluate the
business needs and determine what benefits a cloud computing model would bring to your
organization. Whichever cloud model you choose, whether it be private, public, or hybrid,
it needs to map well to the business processes you are trying to achieve.
A private cloud is a cloud delivery model that is owned by a single organization and
enables them to centrally access IT resources from a variety of locations, departments,
and staff. A private cloud solution is implemented behind the corporate firewall and is
maintained by the local IT department. A private cloud utilizes internal resources and
is designed to offer the same benefits of a public cloud without relinquishing control,
security, and recurring costs to a cloud provider. In a private cloud model the same
organization is both the cloud consumer and the cloud provider.
The decision to implement a private cloud is usually driven by the need to maintain
control of the environment because of regulatory or business reasons. For example, a
bank might have data security issues that prevent them from using a public cloud
service, so they might implement a private cloud to achieve the benefits of a cloud
A private cloud is a combination of virtualization, data center automation, chargeback
metering, and identity-based security. Virtualizations allows for easy scalability,
flexible resource management, and maximum hardware utilization. A private cloud solution
also involves having the ability to auto-provision physical host computers through
orchestration software, which is discussed later in this chapter.
One of the downsides to a private cloud is that an organization does not get the return
on investment it does with other cloud models. This is because the organization is still
responsible for running and managing the resources instead of passing that responsibility
to a cloud provider.
Unlike a private cloud that is owned by the organization, a public cloud is a pool of
computing services that are delivered over the Internet via a cloud provider. A cloud
provider makes resources such as applications and storage available to organizations
over the Internet. Public clouds generally use a pay-as-you-go model, which gives
companies the benefit of paying only for the resources that they consume. Public clouds
allow for easy and inexpensive setup because the hardware, application, and bandwidth
costs are covered and maintained by the cloud provider and charged as part of the service agreement.