Above the Clouds: A Berkeley View of Cloud Computing

date

Sep 29, 2024

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Published

Definition

Cloud Computing is the sum of SaaS and Utility Computing, but does not normally include Private Clouds.

From a hardware point of view, three aspects are new in Cloud Computing:

The illusion of infinite computing resources available on demand, thereby eliminating the need for Cloud Computing users to plan far ahead for provisioning;

The elimination of an up-front commitment by Cloud users, thereby allowing companies to start small and increase hardware resources only when there is an increase in their needs; and

The ability to pay for use of computing resources on a short-term basis as needed (e.g., processors by the hour and storage by the day) and release them as needed, thereby rewarding conservation by letting machines and storage go when they are no longer useful.

Classes

Any application needs a model of computation, a model of storage and, assuming the application is even trivially distributed, a model of communication. The statistical multiplexing necessary to achieve elasticity and the illusion of infinite capacity requires resources to be virtualized, so that the implementation of how they are multiplexed and shared can be hidden from the programmer.

Distinguished based on the level of abstraction presented to the programmer and the level of management of the resources.

EC2→Azune→AppEngine

Obstacle

Availability of a Service

whether Utility Computing services will have adequate availability
DDos

Data Lock-In

Software stacks have improved interoperability among platforms, but the APIs for Cloud Computing itself are still essentially proprietary, or at least have not been the subject of active standardization. Thus, customers cannot easily extract their data and programs from one site to run on another

Data Confidentiality and Auditability

Data Transfer Bottlenecks

Economic necessity mandates putting the data near the application, since the cost of wide-area networking has fallen more slowly (and remains relatively higher) than all other IT hardware costs.

Performance Unpredictability

I/O sharing is problematic

Scalable Storage

Bugs in Large-Scale Distributed Systems

Scaling Quickly

Reputation Fate Sharing

Software Licensing

Conclusion

From the cloud provider’s view, the construction of very large datacenters at low cost sites using commodity computing, storage, and networking uncovered the possibility of selling those resources on a pay-as-you-go model below the costs of many medium-sized datacenters, while making a profit by statistically multiplexing among a large group of customers.

From the cloud user’s view, it would be as startling for a new software startup to build its own datacenter as it would for a hardware startup to build its own fabrication line. In addition to startups, many other established organizations take advantage of the elasticity of Cloud Computing regularly, including newspapers like the Washington Post, movie companies like Pixar, and universities like ours.

Above_the_Clouds_A_Berkeley_View_of_Cloud_Computin.pdf