Excerpt:
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.
Private Cloud
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 computing model.
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.
Public Cloud
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.
Public clouds are used when an organization is less likely to need the level of infrastructure and security offered by private clouds. Organizations requiring data security can still utilize public clouds to make their operations significantly more efficient with the storage of nonsensitive content, online document collaboration, and webmail.
A public cloud offers ultimate scalability because cloud resources are available on demand from the cloud provider's vast pool of resources. Organizations do not need to purchase and implement hardware to scale the environment; they just need to purchase more resources from the cloud provider. The availability of the public cloud via an Internet connection allows the services to be used wherever the client is located, making a public cloud location independent. Some examples of public cloud providers are HP Cloud Services, Microsoft Windows Azure, and Amazon Web Services.
Hybrid Cloud
A hybrid cloud is a cloud service that utilizes both private and public clouds to perform distinct functions within the same organization. An organization might have a need for both a local server running specific applications, for security reasons and a public cloud hosting additional files and databases. These two environments would be configured for scalability and interoperability.
In a hybrid cloud model an organization continues to provide and manage some resources internally while other resources are provided externally buy a cloud provider. A hybrid cloud allows an organization to take advantage of the scalability and cost-effectiveness of a public cloud without exposing mission-critical data to a public cloud provider.
A cloud model is defined as a hybrid cloud if an organization is using a public development that sends data to a private cloud. Another example of a hybrid cloud model is when an organization uses multiple SaaS applications and moves that application data between a private cloud or an internal data center.
A cloud is not considered a hybrid if an organization uses SaaS applications and does not move the data to a private cloud or internal data center. A cloud environment is labeled as a hybrid cloud only if there is a combination of private and public clouds or if data is moved between the internal data center and the public cloud.
Community Cloud
A community cloud is a cloud offering where the infrastructure is shared between several organizations from a specific group with common computing needs or objectives. Community clouds are built and operated specifically for a targeted group who have common cloud requirements and whose ultimate goal is to work together to achieve a specific business objective.
Community clouds are usually implemented for organizations working on joint projects that require a central cloud for managing and executing those projects. A finance community cloud, for example, could be set up to provide specific security requirements or optimized to provide low latency to execute financial transactions. A community cloud can be either on premises or off premises and can be managed by a cloud provider or by the organizations themselves.
Reader Andreas Wozny says,"I bought this book to study for the corresponding exam and passed the exam using it. That said the book covers most of the stuff from the blueprint and the CDROM provides hundreds of test questions which are close to what you should expect on the real exam. I also used it as in introduction into cloud technology but in that respect it fell somewhat short due to its nature of being a certification guide. If you plan on going for the exam this is the book for you plus some supplementary reading according to the blueprint.
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