Information Technology Reference
In-Depth Information
The definition of cloud computing as per Gartner is “A style of computing where
massively scalable IT-enable capabilities are delivered as a service to external
customers using internal technologies”. Cloud computing is delivery of computing as
a services rather than product. Cloud 'Services' refer to those types of services that
are exposed by cloud trafficker and that can be used by cloud consumer on a 'pay-per-
use' basis. An ongoing monthly expenses easy to incorporate into budget than large
one-time outlay. In this cancel and change subscription at any time without losing
large initial investment.
In practice, cloud services are classified-Infrastructure as a Services(IaaS),
Software as a Services(SaaS), Platform as a Services(PaaS), Data as a Services
(DaaS)[2].
In Infrastructure as a service large amount computing resources are managed by
IaaS provider which is allocated to user as demanded. IaaS is the concept of providing
Hardware as a Service. IaaS offer basic storage and compute capabilities as
standardized services over the network. Servers, storage systems, switches, routers,
and other systems are pooled and made available to handle workloads that range from
application components to high-performance computing application [2]. There are a
number of successful IaaS providers: Amazon EC2, Joyent, Rack space etc.
Platform as a Service is a way to rent hardware, operating systems, storage and
network capacity over the internet. It delivers a computing platform or software stack as
a service to run applications. This can broadly be defined as application development
environment offered as a 'service' by the vendors. The development community can use
these platforms to code their applications and then deploy the applications on the
infrastructure provided by the cloud vendor. Here again, the responsibility of hosting
and managing the required infrastructure will be with the cloud vendor. AppEngine,
Bungee Connect, LongJump, Force.com, WaveMaker are all instances of PaaS.
Software as a Service also refers to application as a Service. Instead of running as
application locally, the application resides on the cloud and online alternatives such as
access via web interface is provided. SaaS is the service based on the concept of
renting software from a service provider rather than buying it yourself. That
eliminates the need to install. Yahoo mail, Google docs applications, Salesforce.com
CRM apps, Microsoft Exchange Online, Facebook are all instances of SaaS.
Data as a Service is refer data in various formats and from various sources could be
accessed via services by users on network, in a transparent, logical or semantic way.
Users could, for example, manipulate remote data just like operate on a local disk or
access data in a semantic way in the Internet. The DaaS could be found at some
popular IT services, e.g. Google Docs and Adobe Buzzword. A hybrid cloud is a
composition of at least one private cloud and at least one public cloud. In Quality of
services guaranteed the computing Clouds can guarantee QOS for users and Service
Level Agreement is negotiated between cloud provider and user on the level of
availability, serviceability, performance, operation, or other attributes of the service
like billing and even penalties in the case of violation of the SLA[6].
Cloud computing provide services from hardware to application. The services are-
Infrastructure as a Service(IaaS), Software as a Services(SaaS) and Platform as a
Service(PaaS). Proposed methodology is based on Infrastructure as a Service layer for
receive resource on demand.
In this can choice of virtual computer, meaning the can
select a configuration of CPU, memory and storage that is optimal for your
