Which of the following is a cloud infrastructure that is provisioned for exclusive use by a specific community of consumers from organizations that have shared concerns?

Organizations have different needs for cloud services based on the criticality of the applications, sensitivity of data, speed of servicing the requests, safety related aspects, customer requirements, and security requirements. One organization may have two different types of deployment of cloud models applicable to different segments or groups or for different applications within their organization running at the same time.2&4

The four Cloud Deployment Models are: Private Cloud, Public Cloud, Community Cloud, and Hybrid Cloud.

Each of these deployments is discussed in the following sections.

Various Cloud Deployment Models and how they relate to other types of Cloud Deployment Models are illustrated in Figure 13-5.

Figure 13-5. Deployment Model Options

Private Cloud

A private cloud is dedicated and set up for a particular cloud consumer based on their unique high-security needs. However, private cloud comes only at high capital investment as well as high maintenance cost. A private cloud ensures high availability, confidentiality of the data, and complete integrity of the data. A private cloud allows the user to realize the benefits of cloud computing, such as avoiding upfront high capital expenditure, pay as you use model, best in class applications, high end technology, and large and fast storage capability without the security risks of a public cloud environment.

Of course, as this private cloud is dedicated to the cloud consumer and designed as per the requirements / specifications of the cloud consumer, it is relatively costly compared to the other cloud deployment models.

The advantage of this model is that the cloud consumer still has significant control over the cloud infrastructure and can negotiate and agree on clear terms and conditions with the cloud provider, including the security level requirements. The security in this type can be demanded by the cloud consumer and can be provided by the cloud provider.

Public Cloud

Unlike the private cloud, the public cloud is the cheapest option available on the cloud infrastructure and it is available to everybody. Here, the cloud provider leverages upon the huge infrastructure which he can share with a large number of customers as he deems fit. While these are cheaper, the terms and conditions are mostly unilaterally decided by the cloud provider and the cloud consumer has very little say in this. The cloud consumer does not have much control over the cloud provider. Little significant responsibility is assumed by the cloud provider either on the availability or on the security of the information. Hence, the cloud consumer is at the mercy of the situation or the cloud provider most of the time. A public cloud is best for new organizations with no critical data that are looking

for a cost-effective solution. Of course, cloud consumers can request higher service levels and higher assurance but these come at a higher cost and still may not be appropriately serviced. The advantage this provides for the smaller organization is the expertise of the cloud provider which a smaller cloud consumer may not have.

As multiple customers co-exist on the cloud, it may be difficult to monitor the activities of each of these individual customers and hence it is highly difficult and impractical for the most part for the cloud provider to assure high security in this type of deployment model.

Community Cloud

These clouds are set up for collaborative work between the organizations belonging to a particular community like health care, government organizations, or social service organizations with shared objectives. These clouds are set up by the community for use by the organizations within the community. These may be managed by one or more of the organizations belonging to the community or may be managed by a designated outsourced agency or a thirdparty cloud provider. The collaborative set up of such a cloud brings down the cost of such an infrastructure to each organization while bringing the benefits of cloud to all the participants. However, information security may be still a concern as many organizations will be using the cloud and the cloud provider may not have the necessary security expertise. Also, the capability and strength of such a cloud depends upon the capability of those who design and maintain it and the infrastructure they chose to support it.

Hybrid Cloud

An organization may use a hybrid cloud, which is a combination of any of the above three deployment models (Private Cloud, Public Cloud, and Community Cloud). Depending upon the different purposes for which the cloud infrastructure is to be used, different deployment models may be used by a cloud consumer. These may be

requisitioned from different cloud providers. Highly critical and highly confidential applications may go on to private cloud while non-critical, non-sensitive, generic applications may go on to public cloud and community collaborations may be serviced through community clouds.