7. Cloud Deployment Models:
There are many issues to consider when moving an enterprise application to the cloud environment. For example, some service providers are mostly interested in lowering operation cost, while others may prefer high reliability and security. Accordingly, there are different types of clouds, each with its own benefits and drawbacks:
Public Clouds: A cloud in which service providers offer their resources as services to the public. Moreover, the service provider will be the responsible for managing the underlying infrastructure. Public clouds are designed to host multiple customers simultaneously, and they achieve great success through economies of scale. Public clouds offer several key benefits including no initial capital investment on infrastructure and shifting of risks to infrastructure providers. However, public clouds lack fine-grained control over data, network and security settings, which hampers their effectiveness in many business scenarios. Public Clouds are suitable for the companies that wants to reduce their capital investment cost or companies which their IT team lack the required experience to manage and maintain their Data center or to the new companies that don’t know the workload demand for their services. Until they know the real workload, then they can move to the private or hybrid clouds.
Private Clouds: Private Clouds are designed for exclusive use by a single organization. A private cloud may be built and managed by the organization or by external providers. A private cloud offers the highest degree of control over performance, reliability and security. However, they are often criticized for being similar to traditional proprietary server farms and do not provide benefits such as no up-front capital costs but private clouds may be cheaper over the long term than public clouds, since this is essentially owning versus renting. According to several analyses, the breakeven period is between 2 and 3 years .
Community clouds: are similar to private clouds, however more than one organization may participate in the cloud infrastructure. Typically, these organizations share a common mission, goal, or security requirements. The cloud hardware may be managed by one or more of these organizations, or it could be outsourced entirely to a third party.
Hybrid clouds: A hybrid cloud is a combination of public and private cloud models that tries to address the limitations of each approach. In a hybrid cloud, part of the service infrastructure runs in private clouds while the remaining part runs in public clouds. Hybrid clouds offer more flexibility than both public and private clouds. Specifically, they provide tighter control and security over application data compared to public clouds, while still facilitating on-demand service expansion and contraction. On the down side, designing a hybrid cloud requires carefully determining the best split between public and private cloud components. Hybrid clouds are suitable for Companies with seasonal or burst workload usage, so they look to the hybrid cloud model so they can design their internal data center for normal usage, and then allow the burst usage to run in the cloud. Another use case is testing and development environments. If you have ever needed to upgrade or change your organization’s line of business application, you know how many different test and development systems can be required. Even in smaller organization, this extra capacity may be too much for their data center to handle. By leveraging a hybrid cloud, you can migrate those test and development workloads in and out of your data center as need without additional capital expenditures.