Cloud Computing Deployment Model Deployment models broadly characterize the management and disposition of computational resources for delivery of services to consumers
Cloud Computing Deployment Model
Deployment models broadly characterize the management and disposition of computational resources for delivery of services to consumers, as well as the differentiation between classes of consumers. Clouds can also be classified based upon the underlying infrastructure deployment model as Public, Private, Community, or Hybrid clouds. The different infrastructure deployment
models are distinguishing by their architecture, the location of the datacenter where the cloud is realized, and the needs of the cloud provider’s customers (for example, due to regulatory, legal, or other requirements).
A public cloud’s physical infrastructure is owned by a cloud service provider. Such a cloud runs applications from different customers who share this infrastructure and pay for their resource utilization on a utility computing basis. The cloud services are available for anyone to subscribe and to use in a pay-as-you-go manner, A public cloud customer can access these services over the internet from a third-party provider who may share computing resources with many customers.
The public cloud model is widely accepted and adopted by many enterprises because the leading public cloud vendors as Amazon, Microsoft, and Google, have equipped their infrastructure with a vast amount of data centers, enabling users to freely scale and shrink their rented resources with low cost and little management burden 17. 18 Lists some of the advantages and drawbacks of the public cloud.
The advantages of public cloud computing include:
? Data availability and continuous uptime
? 24/7 technical expertise
? On-demand scalability
? Easy and inexpensive setup
? No wasted resources
Drawbacks of the public cloud:
? Data security
Private cloud infrastructure may be set-up On-Premise or off-premise and may be managed either internally or by third-party service providers. Private clouds offer the highest level of security and control but are expensive. A private cloud is built for the exclusive use of one customer, who owns and fully controls this cloud. Additionally, there are variations of this in terms of ownership, operation, etc. The fact that the cloud is used by a specific customer is the distinguishing feature of any private cloud. A private cloud might be owned by the customer, but built, installed, and managed by a third party rather than the customer. The physical servers might be located at the customer’s premises or sited in a collocation facility. The difference between a private cloud and a public cloud is that in a private cloud-based service, data and processes are managed within the organization, a third party, or some combination of them, and it may exist on or off premises. A private cloud provides more security than public clouds because in public cloud the user may not know where their data is stored or how it is backed up and whether unauthorized users can get access to it.
A community cloud falls between public and private clouds with respect to the target set of consumers. It is somewhat similar to a private cloud, but the infrastructure and computational resources are exclusive to two or more organizations 18. The cloud infrastructure is provisioned for exclusive used by a specific community of consumers from organizations that have shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be owned, managed, and operated by one or more of the organizations in the community, a third party, or some combination of them, and it may exist on or off premises. A community cloud provides many of the benefits of scale of the public cloud while retaining greater control over compliance and data privacy.
FIGURE 2.1. COMMUNITY CLOUD MODEL 19
The advantages 18 of community cloud include:
The cost of setting up a communal cloud versus individual private cloud can be cheaper due to the division of costs among all participants.
? Management of the community cloud can be outsourced to a cloud provider. The advantage here is that the provider would be an impartial third party that is bound by contract and that has no preference to any of the clients involved other than what is contractually mandated.
? Tools residing in the community cloud can be used to leverage the information stored to serve consumers and the supply chain, such as return tracking and just-in-time production and distribution.
? Since it is managed by contract with an impartial third party or by one of or the combined expertise of the whole community, it has the advantage of security and privacy over the public cloud.
Drawbacks of community cloud:
? Costs higher than public cloud.
The cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load balancing between clouds). A hybrid cloud is typically offered in one of two ways: a vendor has a private cloud and forms a partnership with a public cloud provider, or a public cloud provider forms a partnership with a vendor that provides private cloud platforms. In a hybrid cloud, an organization provides and manages some resources in-house and some out-house. Hybrid clouds 18 offer the cost and scale benefits of public clouds, while also offering the security and control of private clouds. The advantages of the hybrid cloud include:
? Reduces capital expenses as part of the organization’s infrastructure, needs are outsourced to public cloud providers.
? Improves resource allocation for temporary projects at a vastly reduced cost because the use of public cloud removes the need for investments to carry out these projects.
? Helps optimize the infrastructure spending during different stages of the application lifecycle. Public clouds can be tapped for development and testing while private clouds can be used for production. More importantly, public clouds can be used to retire applications, which may be no longer needed because of the move to SaaS, at much lower costs than dedicated on-premise infrastructure.
? Offers both the controls available in a private cloud deployment along with the ability to rapidly scale using the public cloud.
? Supplies support for cloud-bursting.
? Provides drastic improvements in the overall organizational agility, because of the ability to leverage public clouds, leading to increased opportunities.
Drawbacks of the hybrid cloud are:
? As a hybrid cloud extends the IT perimeter outside the organizational boundaries, it opens up a larger surface area for attacks with a section of the hybrid cloud infrastructure under the control of the service provider.
? An easier approach to solving the identity, needs of hybrid clouds is to extend the existing enterprise identity and access management to the public clouds. This opens up concerns about how this approach will affect the enterprise identity and its impact on the organization’s security.
? When organizations manage complex hybrid cloud environments using a management tool, either as a part of the cloud platform or as a third-party tool, organizations should consider the security implications of using such a tool. For example, the management tool should be able to handle the identity and enforce security uniformly across hybrid cloud environments.
? A hybrid cloud makes the data flow from a private environment to a public cloud much easier. There are privacy and integrity concerns associated with such data movement because the privacy controls in the public cloud environment vary significantly from the private cloud.
? There are risks associated with the security policies spanning the hybrid cloud environment such as issues with how encryption keys are managed in a public cloud compared to a pure private cloud environment.