Lecture 9: What is cloud computing

Chapter 1 of the Second Reference Book

Significance of Cloud Computing

• A research from IDC predicts that the cloud will generate nearly 14 million new jobs worldwide by 2015 [TopStories at Microsoft.com, March 5, 2012].

• In the state of Georgia, Silver lining, a cloud computing company is in the process of adding 900 new jobs in Atlanta [Atlanta Business Chronicle, Feb. 1, 2013]

Defintion of Cloud Computing

• In a simplest sense, Cloud represents a network and, more specifically, the global Internet

• Cloud Computing is the use of computational resources that are hosted remotely and delivered through the Internet

• There are many definitions of Cloud Computing. (e.g., definition by Gartner, Forrester, Wikipedia, the 451 Group, Nist)

• Definition by NIST

Cloud Computing is a model for enabling convenient, on-demand network access to a shared pool of conifgurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.

• None of the definitions is universally accepted.

• Each definition emphasizes some aspects of cloud computing, but do not provides a complete description.

Why using “cloud”

• In order to understand cloud computing, one obvious place to start is the cloud metaphor itself.

• Why we don’t call it forest computing or ocean computing.

• A cloud has long been used in network diagrams to represent a sort of black box where the interfaces are well known but the internal routing and processing is not visible to the network users.

• A cloud, by nature, is opaque

• A could is typcially very large and distant.

• Furthermore, clouds may be overlapping; they may dynamically intersect or split.

Key attributes of cloud computing

• Off-Premise• Elasticity• Flexible billing• Virtualization• Service delivery• Universal access• Simplified management• Affordable resources• Multi-tenancy• Service level management

Key attributes of cloud computing

• Off-Premise: the service is hosted and delivered from a location that belongs to a service provider.

- The service is deliverred over the public Internet

- Computing processes occure outside the company firewall.

• Elasticity: cloud computing provides an elastic provisioning mechanism for resource allocation, so that resources can be scaled both up and down very rapidly on demand.

• Flexible Billing: Cloud computing typically charges users by fine-grained metering of resource usages.

• Virtualization: cloud services are usually offerred through an abstracted infrastructure, which leverage various virtualization mechanisms.

• Service delivery: cloud functionality is often available as a service. Typically the services offer programmatic interfaces in addition to the user interfaces.

• Universal access: Pooled resources are available to anyone authorized to utilize them; Location independence and high levels of resilience allow for an always connected user experience.

• Simplified management: - Administration is simplified through

automatic provisioning to meet scalability requirements;

- user self-service expedites businesss process; - programmatically accessible resources

facilites integration into enterprise management frameworks

• Affordable resources: The cost of resources is dramatically reduced for two reasons:

- From the user side, there is no requirement for captial expenditures on fixed purchases

- From the service provider side, the economy of scale of the service providers allow them to optimize their cost structure with commodity hardware and fine-tuned operational procedures that are not easily matched by most companies.

• Multi-tenancy: The cloud is used by many organizations (tenants). It can protect and isolate each tenant from all others.

• Service-level management: Cloud services typically offer a service-level definition that sets the expectation with the customer as to how robust that service will be.

Related Concepts

• Service-oriented architecutre (SOA)• Grid computing• Web 2.0

• Service-oriented architecture (SOA): SOA decomposes the information technology landscape of an enterprise into loosely coupled functional primitives called services.

• These services implement single actions and may be used by many different business applications.

• SOA and Cloud Computing are two independant notions.

- SOA is an architecture, which is technology independent.

• Cloud computing can be a good means of

implementing a SOA design

• Grid Computing: It refers to the use of many interconnected computers to solve a problem through highly parallel computaiton.

• There are conceptual similarity between grid and cloud computing.

- Both involve large interconnected systems of computers - distribute their workload - blur the line between system usage and system

ownership.

• There are also distinctions between these two computing models

- Grid computing is typically used in scientific environment where a job typically requires a huge number of computer processing cycles. It allocates resources in a bath mode.

- Cloud computing is typically process many small tasks simutaneously. It uses real-time resource allocation.

• Web 2.0: It refers to the web as not only a static information source for browser access but a platform for web-based communities to facilitate user participation and collaboration.

• There is no intrinsic connection between cloud computing and web 2.0.

- Cloud computing is a means of delivering services - Web 2.0 is a class of services that may be

deliverred in many different ways.

History of cloud computing

• Amazon was arguably the first company to offer an extensive and thorough set of cloud-based services.

• Why it is Aamzon?

• Amazon started as an online book store in 1995.

• It later diversified its product portfolio to include a wide range of categories.

• It also brokered transactions for fee and developed a successful ecosystem of partnership.

• As Amazon grew, it had to invest larger and larger data center to support its business.

• Its data center was provisioned to guarantee the computing capacity in holiday season.

• However, this overprovisioning resulted in the idle of a major share of its data center for 11 out of 12 months.

• In order to turn their weakness into an opportunity, Amazon lanuched Amazon Web Services that sold some of their idle capacity to other organizations.

• Organizations can take advantage of Amazon’s secure and reliable infrastructure at reasonable prices without making any financial and strategic commitment.