The analysis of the cloud infrastructure in the following chapter is from an organizational point of view. This distinguishes after a separation of the
organizational units of users and providers.
Public, Private and Hybrid Clouds
A public cloud refers to all cloud offerings in which providers and users do not belong to the same organization.33 The providers make their cloud publicly accessible and usually offer a web interface, with which the users themselves can adjust the performance. This cloud model is always based on a commercial business model. This means that only the resources consumed by the user are billed to the user. A particular risk is that sensitive data leaves the organization. This creates a so-called lock-in. This refers to a condition in which the customer is bound to a manufacturer in this case provider. And only comes out of this situation with considerable effort.34 For example, if the organization wants to change the provider, this is very difficult or impossible. This results in bankruptcy or price increases that users have no alternative to reorganize their data.
Remedy is the use of private clouds. This makes compatible alternatives to public clouds possible. Private clouds are operated in the same organization as the users. The main argument for the use of these clouds is usually given to safety aspects.35 Well-known software solutions for private clouds are Eucalyptus see chapter 3.3.7. In the private cloud, control over your own data remains with the company. Thus, sensitive data, e.g. Customer data in eCommerce be better protected. The downside to a private cloud is that it requires its own IT resources. By closely linking the tools to those of the public cloud, it should be possible for them to be used intuitively. In addition, e.g. Eucalyptus’ developers are striving to stick to Amazon’s cloud system to eventually scale private clouds into a public cloud.36
It is also possible to combine private and public clouds. This scenario is called hybrid clouds. In such a scenario, peak loads can be covered with resources in one or more public clouds. The normal operation takes place via the private resources. From the security point of view, however, one should consider that only uncritical data may be outsourced.37 The following figure graphically illustrates the interplay between the Cloud infrastructures just mentioned.
Changes through cloud computing
Cloud computing combines the potential to sustainably change the way individuals use and deliver resources. Time savings, minimizing barriers to new application adoption, and cost savings are the key benefits of cloud computing.
Basically, cloud offerings are not limited to applications. It is generally possible to run any application in a cloud. The usage may vary. On the one hand, cloud offers can be used once for specific needs. Take, for example, the gigantic task of the New York Times, which transformed eleven million articles from historical archives into a world-readable format in 24 hours. This would certainly not have been possible with one’s own computers in one day. That’s why the New York Times relied on cloud computing.42 On the other hand, intercepting peak loads or bridging low traffic are other uses of cloud services. Here, the load behavior is monitored by monitoring applications and possibly influenced by stored virtual server instances. This dynamic adaptation of resources can reduce fixed costs. This is in contrast to acquisition or rental costs, where resources are purchased or rented over a period of time. The usage-dependent use results in a high degree of elasticity and the risk minimization of insufficiently available hardware. From own experience an optimal utilization in data centers is usually not possible in practice. An unexpected need for resources usually can not be quickly supported. In addition, the resource requirement is unpredictable. Many of these applications are severely affected by eCommerce. On the one hand, there is the seasonal trend and, on the other hand, the temporary events triggered by, for example, special special offers.