We have seen what is cloud computing and what are the types of service models . Now we will see how organization adopt cloud technology .
Cloud Deployment Models
Now every organization moving to cloud in order to cut capital expenditure and to control the operating costs but cloud may bring security risks and challenges for IT Management which can be more expensive when considering the cost saving achieved by moving to the cloud.
Therefore, it is very important for businesses to understand their requirements before opting for various deployment models available on the cloud.
A cloud deployment model represents a specific type of cloud environment, primarily distinguished by ownership, size, and access.
According NIST, there are primarily four cloud deployment models.
- Public Cloud
- Private Cloud
- Service Hybrid Cloud
- Community Cloud
A public cloud is a publicly accessible cloud environment means public can access the over a network. This service can be provided by a vendor free of charge or on the basis of a pay-per-user license policy.
All IT activities / functions are provided as a service, over the internet.
Public cloud is better suited for business requirements which require managing the load; host application that is SaaS-based and manage applications that many users consume. Due to the decreased capital overheads and operational cost this model is economical. The dealer may provide the service free or in the form of the license policy like pay per user. The cost is shared by all the users, so public cloud profits the customers more by achieving economies of scale.
E.g.: Google, Amazon EC2 service
A private cloud is used by a single organization so it is also called as internal cloud. Private cloud allows an organization to centralized access to its IT resources irrespective of locations, different departments or different parts of an organization.
So we can say that private clouds have more security to its IT resources compared to public cloud but it is expensive compared to public cloud.
IT capabilities provided as a service, over the internet with enterprise and behind the firewall means Security concerns are addressed through secure-access VPN or by the physical location within the client’s firewall system.
A Hybrid cloud is a cloud environment which is comprised of two or more different cloud deployment models. For example, a cloud consumer may choose to deploy cloud services processing sensitive data to a private cloud and other, less sensitive cloud services to a public cloud.
This model is also used for handling cloud bursting, which refers to a scenario where the existing private cloud infrastructure is not able to handle load spikes and requires a fallback option to support the load. Hence, the cloud migrates workloads between public and private hosting without any inconvenience to the users.
Many PaaS deployments expose their APIs, which can be further integrated with internal applications or applications hosted on a private cloud, while still maintaining the security aspects
E.g: Microsoft Azure and Force.com
A community cloud is similar to a public cloud except that its access is limited to a specific community of cloud consumers. In the community deployment model, the cloud infrastructure is shared by several organizations with the same policy and compliance considerations. This helps to further reduce costs as compared to a private cloud, as it is shared by larger group.
Membership in the community does not necessarily guarantee access to or control of all the cloud’s IT resources. Parties outside the community are generally not granted access unless allowed by the community.
Fig: Cloud Deployment Models
Conceptual Reference Architecture
An overview of the NIST cloud computing reference architecture, which identifies the major actors, their activities and functions in cloud computing. The diagram depicts a generic high-level architecture and is intended to facilitate the understanding of the requirements, uses, characteristics and standards of cloud computing.
Fig : Cloud conceptual reference architecture
In our next article wee will see in detail about cloud reference architecture.
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