What is Cloud Computing?

CloudComputing

• Cloud Computing is a general term used to describe a new class of network based computing that takes place over the Internet,

– basically a step on from Utility Computing

– a collection/group of integrated and networked hardware, software and Internet infrastructure (called a platform).

– Using the Internet for communication and transport provides hardware, software and networking services to clients

• These platforms hide the complexity and details of the underlying infrastructure from users and applications by providing very simple graphical interface or API (Applications Programming Interface).

• In addition, the platform provides on demand services, that are always on, anywhere, anytime and any place.

• Pay for use and as needed, elastic

– scale up and down in capacity and functionalities

• The hardware and software services are available to

– general public, enterprises, corporations and businesses markets

• Cloud computing is an umbrella term used to refer to Internet based development and services

• A number of characteristics define cloud data, applications services and infrastructure:

– Remotely hosted: Services or data are hosted on remote infrastructure.

– Ubiquitous: Services or data are available from anywhere.

– Commodified: The result is a utility computing model similar to traditional that of traditional utilities, like gas and electricity - you pay for what you would want!

Basic Cloud Characteristics

• The “no-need-to-know” in terms of the underlying details of infrastructure, applications interface with the infrastructure via the APIs.

• The “flexibility and elasticity” allows these systems to scale up and down at will

– utilising the resources of all kinds

• CPU, storage, server capacity, load balancing, and databases

• The “pay as much as used and needed” type of utility computing and the “always on!, anywhere and any place” type of network-based computing.

• Cloud are transparent to users and applications, they can be built in multiple ways

– branded products, proprietary open source, hardware or software, or just off-the-shelf PCs.

• In general, they are built on clusters of PC servers and off-the-shelf components plus Open Source software combined with in-house applications and/or system software.

Software as a Service (SaaS)

• SaaS is a model of software deployment where an application is hosted as a service provided to customers across the Internet.

• Saas alleviates the burden of software maintenance/support

– but users relinquish control over software versions and requirements.

• Terms that are used in this sphere include

– Platform as a Service (PaaS) and

– Infrastructure as a Service (IaaS)

Virtualization

• Virtual workspaces:

– An abstraction of an execution environment that can be made dynamically available to authorized clients by using well-defined protocols,

– Resource quota (e.g. CPU, memory share),

– Software configuration (e.g. O/S, provided services).