Understanding Cloud Computing

     Cloud computing is a style of computing in     Vmware, Sun Microsystems, IBM, Amazon,
which dynamically scalable and often virtualizedGoogle, Microsoft and Yahoo are some of the major
resources are provided as a service over thecloud computing service providers. Cloud services are
Internet. Users need not have knowledge of,being adopted by individual users through large
expertise in, or control over the technologyenterprises including vmware, General Electric and
infrastructure in the "cloud" that supports them. CloudProcter & Gamble.
computing is a method of delivering hosted servicesCloud computing types
-- Infrastructure-as-a-Service (IaaS),Public cloud
Platform-as-a-Service (PaaS) and     Public cloud or external cloud describes cloud
Software-as-a-Service (SaaS) – over the Internetcomputing in the traditional mainstream sense,
in a fast, cost-effective way. The technology haswhereby resources are dynamically provisioned on a
gained popularity in a weakened economy asfine-grained, self-service basis over the Internet, via
enterprises seek ways to save money, but asweb applications/web services, from an off-site
always, this emerging technology presents certainthird-party provider who shares resources and bills on
risks, and it could open an organization to securitya fine-grained utility computing basis.
vulnerabilities and threats. Hybrid cloud
    The concept generally incorporates     A hybrid cloud environment consisting of
combinations of  infrastructure as a service (IaaS) ,multiple internal and/or external providers "will be
platform as a service (PaaS), software as a servicetypical for most enterprises".
(SaaS) . Cloud computing services often providePrivate cloud
common business applications online that are     Private cloud and internal cloud are neologisms
accessed from a web browser, while the softwarethat some vendors have recently used to describe
and data are stored on the servers. Cloud computingofferings that emulate cloud computing on private
can be confused with  Grid computing  which is anetworks. These (typically virtualization automation)
form of distributed computing whereby a 'super andproducts claim to "deliver some benefits of cloud
virtual computer' is composed of a cluster ofcomputing without the pitfalls", capitalising on data
networked, loosely-coupled computers, acting insecurity, corporate governance, and reliability
concert to perform very large tasks and  Utilityconcerns. They have been criticised on the basis that
computing – the packaging of computingusers "still have to buy, build, and manage them" and
resources, such as computation and storage, as aas such do not benefit from lower up-front capital
metered service similar to a traditional public utilitycosts and less hands-on management, essentially
such as electricity"[lacking] the economic model that makes cloud
Characteristicscomputing such an intriguing concept".
    Cloud computing customers do not generallyCloud Computing and Security Issues
own the physical infrastructure serving as host to the     The benefits of virtualization and cloud
software platform in question. Instead, they avoidcomputing are transforming the way we look at IT
capital expenditure by renting usage from aoutsourcing for development, testing, and
third-party provider. They consume resources as aproduction.  Existing skills, processes, and projects
service and pay only for resources that they use.seem to translate naturally to a virtualized
Many cloud-computing offerings employ the utilityenvironment, and few obstacles seem to impede the
computing model, which is analogous to howadoption of the cloud model for production. 
traditional utility services (such as electricity) arePractitioners and the media alike have touted the
consumed, while others bill on a subscription basis.potential security issues of virtualization.  The cloud
Sharing "perishable and intangible" computing powerbrings with it a layer of additional security
among multiple tenants can improve utilization rates,considerations, in terms of both technology and
as servers are not unnecessarily left idle (which canprocess.
reduce costs significantly while increasing the speed     This layer of additional security isn’t
of application development). A side effect of thisnecessarily scary or complicated.  But right now,
approach is that overall computer usage risestrust in the security of cloud computing is the number
dramatically, as customers do not have to engineerone impediment to its growth.  This article takes a
for peak load limits. Additionally, "increased high-speedlook at the cloud from various points of view.  I will
bandwidth" makes it possible to receive the samecompare real-world examples to look at security
response times from centralized infrastructure atimplications of the Cloud, and show how they
other sites.integrate with traditional security processes.
Companies