Cloud computing is software, data access, computation, and storage services provided to clients through the Internet.
Cloud computing can be implemented in several different ways, including the following:
|Public cloud||A public cloud can be accessed by anyone. Cloud-based computing resources—such as platforms, applications, storage, or other resources—are made available to the general public by a cloud service provider. The service provider may or may not require a fee for using these resources. For example, Google provides many publicly-accessible cloud applications, such as Gmail and Google Docs.|
|Private cloud||A private cloud provides resources to a single organization. Access is restricted to only the users within the organization. Private clouds can be hosted internally, but because of the expense and expertise required to do so, they are typically hosted externally by a third-party. An organization commonly enters into an agreement with a cloud service provider, which provides secure access to cloud-based resources. The organization’s data is kept separate and secure from any other organization using the same service provider.|
|Community cloud||A community cloud is designed to be shared by several organizations. Access is restricted to only users within the organizations who are sharing the community cloud infrastructure. Private clouds can be hosted internally, with each organization sharing the cost of implementation and maintenance. However, because of the expense and expertise required to do so, community clouds are commonly hosted externally by a third-party.|
|Hybrid cloud||A hybrid cloud is composed of a combination of public, private, and community cloud resources from different service providers. The goal behind a hybrid cloud is to expand the functionality of a given cloud service by integrating it with other cloud services.|
The advantages of cloud computing are:
Cloud computing service models include the following:
|Infrastructure as a Service (IaaS)||Infrastructure as a Service (IaaS) delivers infrastructure to the client, such as processing, storage, networks, and virtualized environments. The client deploys and runs software without purchasing servers, data-center space, or network equipment.|
|Platform as a Service (PaaS)||Platform as a Service (PaaS) delivers everything a developer needs to build an application. The deployment comes without the cost and complexity of buying and managing the underlying hardware and software layers.|
|Software as a Service (SaaS)||Software as a Service (SaaS) delivers software applications to the client either over the Internet or on a local area network. SaaS can be:
Cloud computing service providers reduce the risk of security breaches through the following actions:
Cloud-based services can be hosted externally by third-party service providers or internally on your own virtualization infrastructure. For example, internal private clouds are commonly used to provide a Virtual Desktop Infrastructure (VDI). Using VDI, user desktops are virtualized, running on high-end hardware in the data center instead of on the end-user’s workstation hardware. The physical workstation is merely used to establish a remote connection to the user’s virtualized desktop. This is sometimes called a thin client deployment because most of the computing power is provided by servers in the data center. Traditional deployments, where most of the processing load is handled by the local workstation, are called thick client deployments.
Using VDI provides increased flexibility, enhanced security, efficient management, and better data protection than the traditional workstation-based desktop model. Consider the following advantages: