Testing and Deployment: Quality Is King - Deploying and Managing a Cloud Infrastructure - page 289

Community Cloud
A community cloud is a partnership between related organizations, such as governmental
or educational institutions, to share cloud computing resources for a focused purpose (such
as research projects). A community cloud is usually set up using local and private resources
that can be accessed remotely by partner organizations.
Each partner organization that participates in the setup of a joint community cloud is
responsible for the operation and maintenance of their own infrastructure. The biggest advan-
tage of this model is that it provides greater cost savings than a private cloud while compromis-
ing some of the stringent security and privacy requirements. This is usually considered fine
because there is only a limited group of partners who will have access to the cloud.
This model is well suited for organizations that share similar goals and common security
requirements and legal policies. The cloud can be managed by partner organizations or by
a third-party provider.
This model, however, comes with a downside. Because each group of members operates
and maintains its own part of the cloud, things can become slightly complex. Installation
of new hardware/software and troubleshooting and diagnosis can incur issues regarding
communication between partners and can cause undesired delays.
Public Cloud
Public clouds reside over host data center resources and are accessible to registered and pay-
ing users from anywhere in the world. This is the deployment model that commonly repre-
sents cloud computing. In this model, all the physical resources are owned and operated by
a third-party cloud provider. Multiple clients—individuals or corporations—utilize these
resources through a combination of web interfaces and CLI tools. The infrastructure can
be used by clients to dynamically provision services that are billed based on usage.
This model provides two advantages: The first is that it has the highest degree of cost
savings because the clients only need to pay for usage (operations) and not for maintenance
of infrastructure. The infrastructure cost is shared between clients, thus providing econo-
mies of scale. The second advantage is the readiness and availability of the resources.
The biggest challenge (and criticism) of the public cloud model is IP and data control.
For organizations that directly deal with people or their personal data, including telecom,
finance, and market research, data is the most important asset as well as a liability (if it gets
stolen, lost, or corrupted). Data control, security, and privacy are issues that depend on a
multitude of factors, including the type of data and how sensitive it is along with industry,
local, and federal laws concerning the data. Companies that would like to use a public cloud
provider might find themselves limited and restricted by transparent redirection of cloud
services to data centers in variable locations. The reason is that the transparent redirection
presents regulatory and legislative concerns for local and federal mandates demanding data
accountability and governance.