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July
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Margherita Hack
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Idiom
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Laurel and Hardy
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Cloud computing
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Fast food
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Coursera
-
Tour de France
-
English modal verbs
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Hartz concept
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American Civil War
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Florence
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Rita Levi Montalcini
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Flier (pamphlet)
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Credit rating agency
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Crusades
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Web browser
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David Bowie
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English people
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Cyberwarfare
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Password
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iOS 7
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Massive open online course
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Arthur Conan Doyle
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Defense of Marriage Act
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List of Italian musical terms used in English
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Number
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Unique selling proposition (USP)
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Transatlantic Free Trade Area
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Robin Hood
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Louvre
|
WIKIMAG n. 8 - Luglio 2013
Cloud computing
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Cloud computing is a colloquial expression used to describe a
variety of different
computing concepts that involve a large number of computers that are
connected through a real-time communication
network (typically the
Internet).[1]
Cloud computing is a
jargon term
without a commonly accepted non-ambiguous scientific or technical
definition. In science, cloud computing is a synonym for
distributed computing over a network and means the ability to run a
program on many connected computers at the same time. The popularity of
the term can be attributed to its use in marketing to sell hosted
services in the sense of
application service provisioning that run
client server software on a remote location.
Cloud computing logical diagram
Advantages
Cloud computing relies on sharing of resources to achieve coherence
and
economies of scale similar to a
utility (like the
electricity grid) over a network.[2]
At the foundation of cloud computing is the broader concept of
converged infrastructure and
shared services.
The cloud also focuses on maximizing the effectiveness of the shared
resources. Cloud resources are usually not only shared by multiple users
but as well as dynamically re-allocated as per demand. This can work for
allocating resources to users in different time zones. For example, a
cloud computer facility which serves European users during European
business hours with a specific application (e.g. email) while the same
resources are getting reallocated and serve North American users during
North America's business hours with another application (e.g. web
server). This approach should maximize the use of computing powers thus
reducing environmental damage as well, since less power, air
conditioning, rackspace, and so on, is required for the same functions.
The term moving cloud also refers to an organization moving away from
a traditional capex model (buy the dedicated hardware and depreciate it
over a period of time) to the opex model (use a shared cloud
infrastructure and pay as you use it)
Proponents claim that cloud computing allows companies to avoid
upfront infrastructure costs, and focus on projects that differentiate
their businesses instead of infrastructure.[3]
Proponents also claim that cloud computing allows enterprises to get
their applications up and running faster, with improved manageability
and less maintenance, and enables IT to more rapidly adjust resources to
meet fluctuating and unpredictable business demand.[3][4][5]
Hosted services
In marketing, cloud computing is mostly used to sell hosted services
in the sense of
Application Service Provisioning that run
client server software on a remote location. Such services are given
popular acronyms like 'SaaS' (Software as a Service), 'PaaS' (Platform
as a Service). End users access cloud-based
applications through a
web browser or a light-weight desktop or
mobile app while the
business software and user's data are stored on servers at a remote
location.
History
The 1950s
The underlying concept of cloud computing dates back to the 1950s,
when large-scale
mainframe computers became available in academia and corporations,
accessible via
thin clients/terminal
computers, often referred to as "dumb terminals", because they were used
for communications but had no internal computational capacities. To make
more efficient use of costly mainframes, a practice evolved that allowed
multiple users to share both the physical access to the computer from
multiple terminals as well as to share the
CPU time. This eliminated periods of inactivity on the mainframe and
allowed for a greater return on the investment. The practice of sharing
CPU time on a mainframe became known in the industry as
time-sharing.[6]
The
1960's–1990's
John McCarthy opined in the 1960s that "computation may someday be
organized as a
public utility."[7]
Almost all the modern-day characteristics of cloud computing (elastic
provision, provided as a utility, online, illusion of infinite supply),
the comparison to the electricity industry and the use of public,
private, government, and community forms, were thoroughly explored in
Douglas Parkhill's 1966 book, The Challenge of the Computer
Utility. Other scholars have shown that cloud computing's roots go
all the way back to the 1950s when scientist
Herb Grosch (the author of
Grosch's law) postulated that the entire world would operate on dumb
terminals powered by about 15 large data centers.[8]
Due to the expense of these powerful computers, many corporations and
other entities could avail themselves of computing capability through
time sharing and several organizations, such as GE's GEISCO, IBM
subsidiary The
Service Bureau Corporation (SBC, founded in 1957), Tymshare (founded
in 1966), National CSS (founded in 1967 and bought by Dun & Bradstreet
in 1979), Dial Data (bought by Tymshare in 1968), and
Bolt, Beranek and Newman (BBN) marketed time sharing as a commercial
venture.
The 1990s
In the 1990s, telecommunications companies, who previously offered
primarily dedicated point-to-point data circuits, began offering
virtual private network (VPN) services with comparable quality of
service, but at a lower cost. By switching traffic as they saw fit to
balance server use, they could use overall network bandwidth more
effectively. They began to use the cloud symbol to denote the
demarcation point between what the provider was responsible for and what
users were responsible for. Cloud computing extends this boundary to
cover servers as well as the network infrastructure.[9]
As computers became more prevalent, scientists and technologists
explored ways to make large-scale computing power available to more
users through time sharing, experimenting with algorithms to provide the
optimal use of the infrastructure, platform and applications with
prioritized access to the CPU and efficiency for the end users.[10]
Since 2000
After the
dot-com bubble,
Amazon played a key role in all the development of cloud computing
by modernizing their
data centers, which, like most
computer networks, were using as little as 10% of their capacity at
any one time, just to leave room for occasional spikes. Having found
that the new cloud architecture resulted in significant internal
efficiency improvements whereby small, fast-moving "two-pizza teams"
(teams small enough to feed with two pizzas) could add new features
faster and more easily, Amazon initiated a new product development
effort to provide cloud computing to external customers, and launched
Amazon Web Services (AWS) on a utility computing basis in 2006.[11][12]
In early 2008,
Eucalyptus became the first open-source, AWS API-compatible platform
for deploying private clouds. In early 2008,
OpenNebula, enhanced in the RESERVOIR European Commission-funded
project, became the first open-source software for deploying private and
hybrid clouds, and for the federation of clouds.[13]
In the same year, efforts were focused on providing
quality of service guarantees (as required by real-time interactive
applications) to cloud-based infrastructures, in the framework of the
IRMOS European Commission-funded project, resulting to a real-time
cloud environment.[14]
By mid-2008, Gartner saw an opportunity for cloud computing "to shape
the relationship among consumers of IT services, those who use IT
services and those who sell them"[15]
and observed that "organizations are switching from company-owned
hardware and software assets to per-use service-based models" so that
the "projected shift to computing ... will result in dramatic growth in
IT products in some areas and significant reductions in other areas."[16]
On March 1, 2011, IBM announced the
IBM SmartCloud framework to support Smarter Planet.[17]
Among the various components of the Smarter Computing foundation, cloud
computing is a critical piece.
Growth and
popularity
The development of the Internet from being document centric via
semantic data towards more and more services was described as "Dynamic
Web".[18]
This contribution focused in particular in the need for better meta-data
able to describe not only implementation details but also conceptual
details of model-based applications.
The ubiquitous availability of high-capacity networks, low-cost
computers and storage devices as well as the widespread adoption of
hardware virtualization,
service-oriented architecture,
autonomic, and utility computing have led to a growth in cloud
computing.[19][20][21]
Financials Cloud vendors are experiencing growth rates of 90% per
annum.[22]
Origin of the term
The origin of the term cloud computing is unclear. The
expression cloud is commonly used in science to describe a large
agglomeration of objects that visually appear from a distance as a cloud
and describes any set of things whose details are not inspected further
in a given context.
- Meteorology: a weather cloud is an agglomeration.
- Mathematics: a large number of points in a coordinate system in
mathematics is seen as a point cloud;
- Astronomy: many stars that crowd together are seen as star
clouds (also known as star mist) in the sky, e.g. the Milky Way;
- Physics: The indeterminate position of electrons around an
atomic kernel appears like a cloud to a distant observer;
- Video Games: "The Cloud" was what followed Mario characters
around, allowing them to store and access extra items;
In analogy to above usage the word cloud was used as a
metaphor for the Internet and a standardized cloud-like shape was used
to denote a network on telephony schematics and later to depict the
Internet in
computer network diagrams. The cloud symbol was used to represent
the Internet as early as 1994.[23][24]
Servers were then shown connected to, but external to, the cloud symbol.
Urban legends claim that usage of the expression is directly derived
from the practice of using drawings of stylized clouds to denote
networks in diagrams of computing and communications systems.
The term became popular after
Amazon.com introduced the
Elastic Compute Cloud in 2006.
Similar
systems and concepts
Cloud Computing is the result of evolution and adoption of existing
technologies and paradigms. The goal of cloud computing is to allow
users to take benefit from all of these technologies, without the need
for deep knowledge about or expertise with each one of them. The cloud
aims to cut costs, and help the users focus on their core business
instead of being impeded by IT obstacles.[25]
The main enabling technology for cloud computing is
virtualization. Virtualization abstracts the physical
infrastructure, which is the most rigid component, and makes it
available as a soft component that is easy to use and manage. By doing
so, virtualization provides the agility required to speed up IT
operations, and reduces cost by increasing infrastructure
utilization. On the other hand, autonomic computing automates the
process through which the user can provision resources
on-demand. By minimizing user involvement, automation speeds up the
process and reduces the possibility of human errors.[25]
Users face difficult business problems every day. Cloud computing
adopts concepts from
Service-oriented Architecture (SOA) that can help the user break
these problems into
services that can be integrated to provide a solution. Cloud
computing provides all of its resources as services, and makes use of
the well-established standards and best practices gained in the domain
of SOA to allow global and easy access to cloud services in a
standardized way.
Cloud computing also leverages concepts from
utility computing in order to provide
metrics for the services used. Such metrics are at the core of the
public cloud pay-per-use models. In addition, measured services are an
essential part of the feedback loop in autonomic computing, allowing
services to scale on-demand and to perform automatic failure recovery.
Cloud computing is a kind of
grid computing; it has evolved from grid computing by addressing the
QoS (quality of service) and
reliability problems. Cloud computing provides the tools and
technologies to build data/compute intensive parallel applications with
much more affordable prices compared to traditional
parallel computing techniques.[25]
Cloud computing shares characteristics with:
-
Client–server model — Client–server computing refers
broadly to any
distributed application that distinguishes between service
providers (servers) and service requesters (clients).[26]
-
Grid computing — "A form of
distributed and
parallel computing, whereby a 'super and virtual computer' is
composed of a
cluster of networked,
loosely coupled computers acting in concert to perform very
large tasks."
-
Mainframe computer — Powerful computers used mainly by large
organizations for critical applications, typically bulk data
processing such as
census,
industry and consumer statistics, police and secret intelligence
services,
enterprise resource planning, and financial
transaction processing.[27]
-
Utility computing — The "packaging of
computing resources, such as computation and storage, as a
metered service similar to a traditional public utility, such as
electricity."[28][29]
-
Peer-to-peer means distributed architecture without the need for
central coordination. Participants are both suppliers and consumers
of resources (in contrast to the traditional client–server model).
-
Cloud gaming—also known as on-demand gaming—is a way of
delivering games to computers. Gaming data is stored in the
provider's server, so that gaming is independent of client computers
used to play the game.
Characteristics
Cloud computing exhibits the following key characteristics:
- Agility improves with users' ability to re-provision
technological infrastructure resources.
-
Application programming interface (API) accessibility to
software that enables machines to interact with cloud software in
the same way that a traditional user interface (e.g., a computer
desktop) facilitates interaction between humans and computers. Cloud
computing systems typically use Representational State Transfer (REST)-based
APIs.
- Cost is claimed to be reduced, and in a public cloud
delivery model
capital expenditure is converted to
operational expenditure.[30]
This is purported to lower
barriers to entry, as infrastructure is typically provided by a
third-party and does not need to be purchased for one-time or
infrequent intensive computing tasks. Pricing on a utility computing
basis is fine-grained with usage-based options and fewer IT skills
are required for implementation (in-house).[31]
The e-FISCAL project's state of the art repository[32]
contains several articles looking into cost aspects in more detail,
most of them concluding that costs savings depend on the type of
activities supported and the type of infrastructure available
in-house.
-
Device and location independence[33]
enable users to access systems using a web browser regardless of
their location or what device they are using (e.g., PC, mobile
phone). As infrastructure is off-site (typically provided by a
third-party) and accessed via the Internet, users can connect from
anywhere.[31]
-
Virtualization technology allows servers and storage devices
to be shared and utilization be increased. Applications can be
easily migrated from one physical server to another.
-
Multitenancy enables sharing of resources and costs across a
large pool of users thus allowing for:
- Centralization of infrastructure in locations with
lower costs (such as real estate, electricity, etc.)
- Peak-load capacity increases (users need not engineer
for highest possible load-levels)
- Utilisation and efficiency improvements for systems
that are often only 10–20% utilised.[11][34]
-
Reliability is improved if multiple redundant sites are
used, which makes well-designed cloud computing suitable for
business continuity and
disaster recovery.[35]
- Scalability and elasticity via dynamic ("on-demand")
provisioning of resources on a fine-grained, self-service basis
near real-time,[36][37]
without users having to engineer for peak loads.[38][39][40]
-
Performance is monitored, and consistent and loosely coupled
architectures are constructed using
web services as the system interface.[31]
-
Security could improve due to centralization of data,
increased security-focused resources, etc., but concerns can persist
about loss of control over certain sensitive data, and the lack of
security for stored kernels.[41]
Security is often as good as or better than other traditional
systems, in part because providers are able to devote resources to
solving security issues that many customers cannot afford.[42]
However, the complexity of security is greatly increased when data
is distributed over a wider area or greater number of devices and in
multi-tenant systems that are being shared by unrelated users. In
addition, user access to security
audit logs may be difficult or impossible. Private cloud
installations are in part motivated by users' desire to retain
control over the infrastructure and avoid losing control of
information security.
-
Maintenance of cloud computing applications is easier,
because they do not need to be installed on each user's computer and
can be accessed from different places.
The National Institute of Standards and Technology's definition of
cloud computing identifies "five essential characteristics":
On-demand self-service. A consumer can unilaterally
provision computing capabilities, such as server time and
network storage, as needed automatically without requiring human
interaction with each service provider.
Broad network access. Capabilities are available over
the network and accessed through standard mechanisms that
promote use by heterogeneous thin or thick client platforms
(e.g., mobile phones, tablets, laptops, and workstations).
Resource pooling. The provider's computing resources
are pooled to serve multiple consumers using a multi-tenant
model, with different physical and virtual resources dynamically
assigned and reassigned according to consumer demand. ...
Rapid elasticity. Capabilities can be elastically
provisioned and released, in some cases automatically, to scale
rapidly outward and inward commensurate with demand. To the
consumer, the capabilities available for provisioning often
appear unlimited and can be appropriated in any quantity at any
time.
Measured service. Cloud systems automatically control and
optimize resource use by leveraging a metering capability at
some level of abstraction appropriate to the type of service
(e.g., storage, processing, bandwidth, and active user
accounts). Resource usage can be monitored, controlled, and
reported, providing transparency for both the provider and
consumer of the utilized service.
—National Institute of Standards and Technology [2]
On-demand
self-service
On-demand self-service allows users to obtain, configure and deploy
cloud services themselves using cloud service catalogues, without
requiring the assistance of IT.[43][44]
This feature is listed by the
National Institute of Standards and Technology (NIST) as a
characteristic of cloud computing.[2]
The self-service requirement of cloud computing prompts
infrastructure vendors to create cloud computing templates, which are
obtained from cloud service catalogues. Manufacturers of such templates
or blueprints include
BMC Software (BMC), with Service Blueprints as part of their cloud
management platform[45]
Hewlett-Packard (HP), which names its templates as HP Cloud Maps[46]
RightScale[47]
and Red
Hat, which names its templates CloudForms.[48]
The templates contain predefined configurations used by consumers to
set up cloud services. The templates or blueprints provide the technical
information necessary to build ready-to-use clouds.[47]
Each template includes specific configuration details for different
cloud infrastructures, with information about servers for specific tasks
such as hosting applications, databases, websites and so on.[47]
The templates also include predefined Web service, the operating system,
the database, security configurations and load balancing.[48]
Cloud computing consumers use cloud templates to move applications
between clouds through a self-service portal. The predefined blueprints
define all that an application requires to run in different
environments. For example, a template could define how the same
application could be deployed in cloud platforms based on Amazon Web
Service, VMware or Red Hat.[49]
The user organization benefits from cloud templates because the
technical aspects of cloud configurations reside in the templates,
letting users to deploy cloud services with a push of a button.[50][51]
Cloud templates can also be used by developers to create a catalog of
cloud services.[52]
Service models
Cloud computing providers offer their services according to several
fundamental models:[2][53]
infrastructure as a service (IaaS), platform as a service (PaaS), and
software as a service (SaaS) where IaaS is the most basic and each
higher model abstracts from the details of the lower models. Other key
components in XaaS are described in a comprehensive taxonomy model
published in 2009,[54]
such as Strategy-as-a-Service, Collaboration-as-a-Service, Business
Process-as-a-Service, Database-as-a-Service, etc. In 2012, network as a
service (NaaS) and communication as a service (CaaS) were officially
included by ITU (International Telecommunication Union) as part of the
basic cloud computing models, recognized service categories of a
telecommunication-centric cloud ecosystem.[55]
Infrastructure as a service (IaaS)
In the most basic cloud-service model, providers of IaaS offer
computers - physical or (more often) virtual machines - and other
resources. (A
hypervisor, such as
Xen or
KVM, runs the virtual machines as guests. Pools of hypervisors
within the cloud operational support-system can support large numbers of
virtual machines and the ability to scale services up and down according
to customers' varying requirements.) IaaS clouds often offer additional
resources such as a virtual-machine
disk image library, raw (block) and file-based storage, firewalls,
load balancers, IP addresses,
virtual local area networks (VLANs), and software bundles.[56]
IaaS-cloud providers supply these resources on-demand from their large
pools installed in
data centers. For
wide-area connectivity, customers can use either the Internet or
carrier clouds (dedicated virtual private networks).
To deploy their applications, cloud users install operating-system
images and their application software on the cloud infrastructure. In
this model, the cloud user patches and maintains the operating systems
and the application software. Cloud providers typically bill IaaS
services on a utility computing basis[citation
needed]: cost reflects the amount of resources
allocated and consumed.
Examples of IaaS providers include:
Amazon EC2,
AirVM,
Azure Services Platform,
DynDNS,
Google Compute Engine,
HP Cloud,
iland,
Joyent,
LeaseWeb,
Linode,
NaviSite,
Oracle Infrastructure as a Service,
Rackspace,
ReadySpace Cloud Services,
ReliaCloud,
Savvis,
SingleHop, and
Terremark
The spending on cloud service is expected to show the largest
increase in the IT marketplace, with North Africa and the Middle East
having growth of over 20% through 2016, according to analysts at
Gartner. The first cloud service in the United Arab Emirates for SMBs
and enterprises was announced June 2013 when the leading telecom
operator in the Middle East and Africa
Etisalat launched its first cloud service in the UAE. IaaS cloud
model was believed to reduce IT costs up to 60% and time to market
faster by up to 90%.
Cloud communications and
cloud telephony, rather than replacing local computing
infrastructure, replace local telecommunications infrastructure with
Voice over IP and other off-site Internet services.
Platform as a service (PaaS)
In the PaaS model, cloud providers deliver a
computing platform typically including operating system, programming
language execution environment, database, and web server. Application
developers can develop and run their software solutions on a cloud
platform without the cost and complexity of buying and managing the
underlying hardware and software layers. With some PaaS offers, the
underlying computer and storage resources scale automatically to match
application demand such that cloud user does not have to allocate
resources manually.
Examples of PaaS include:
AWS Elastic Beanstalk,
Cloud Foundry,
Heroku,
Force.com,
EngineYard,
Mendix,
OpenShift,
Google App Engine,
AppScale,
Windows Azure Cloud Services,
OrangeScape and
Jelastic.
Software as a service (SaaS)
In the
business model using software as a service (SaaS), users are
provided access to application software and databases. Cloud providers
manage the infrastructure and platforms that run the applications. SaaS
is sometimes referred to as "on-demand software" and is usually priced
on a pay-per-use basis. SaaS providers generally price applications
using a subscription fee.
In the SaaS model, cloud providers install and operate application
software in the cloud and cloud users access the software from cloud
clients. Cloud users do not manage the cloud infrastructure and platform
where the application runs. This eliminates the need to install and run
the application on the cloud user's own computers, which simplifies
maintenance and support. Cloud applications are different from other
applications in their scalability—which can be achieved by cloning tasks
onto multiple
virtual machines at run-time to meet changing work demand.[57]
Load balancers distribute the work over the set of virtual machines.
This process is transparent to the cloud user, who sees only a single
access point. To accommodate a large number of cloud users, cloud
applications can be
multitenant, that is, any machine serves more than one cloud
user organization. It is common to refer to special types of cloud based
application software with a similar naming convention:
desktop as a service, business process as a service,
test environment as a service, communication as a service.
The pricing model for SaaS applications is typically a monthly or
yearly flat fee per user,[58]
so price is scalable and adjustable if users are added or removed at any
point.[59]
Examples of SaaS include:
Google Apps,
Microsoft Office 365,
Petrosoft,
Onlive,
GT
Nexus,
Marketo,
Casengo,
TradeCard,
Salesforce and CallidusCloud.
Proponents claim SaaS allows a business the potential to reduce IT
operational costs by outsourcing hardware and software maintenance and
support to the cloud provider. This enables the business to reallocate
IT operations costs away from hardware/software spending and personnel
expenses, towards meeting other goals. In addition, with applications
hosted centrally, updates can be released without the need for users to
install new software. One drawback of SaaS is that the users' data are
stored on the cloud provider's server. As a result, there could be
unauthorized access to the data.
Network as a service (NaaS)
A category of cloud services where the capability provided to the
cloud service user is to use network/transport connectivity services
and/or inter-cloud network connectivity services.[60]
NaaS involves the optimization of resource allocations by considering
network and computing resources as a unified whole.[61]
Traditional NaaS services include flexible and extended VPN, and
bandwidth on demand.[60]
NaaS concept materialization also includes the provision of a virtual
network service by the owners of the network infrastructure to a third
party (VNP – VNO).[62][63]
Cloud clients
Users access cloud computing using networked client devices, such as
desktop computers,
laptops,
tablets and
smartphones. Some of these devices - cloud clients - rely on
cloud computing for all or a majority of their applications so as to be
essentially useless without it. Examples are
thin clients and the browser-based
Chromebook. Many cloud applications do not require specific software
on the client and instead use a web browser to interact with the cloud
application. With
Ajax and
HTML5 these
Web user interfaces can achieve a similar, or even better,
look and feel to native applications. Some cloud applications,
however, support specific client software dedicated to these
applications (e.g.,
virtual desktop clients and most email clients). Some legacy
applications (line of business applications that until now have been
prevalent in
thin client computing) are delivered via a screen-sharing
technology.
Deployment models
Private cloud
Private cloud is cloud infrastructure operated solely for a single
organization, whether managed internally or by a third-party and hosted
internally or externally.[2]
Undertaking a private cloud project requires a significant level and
degree of engagement to virtualize the business environment, and
requires the organization to reevaluate decisions about existing
resources. When done right, it can improve business, but every step in
the project raises security issues that must be addressed to prevent
serious vulnerabilities.[64]
They have attracted criticism because users "still have to buy,
build, and manage them" and thus do not benefit from less hands-on
management,[65]
essentially "[lacking] the economic model that makes cloud computing
such an intriguing concept".[66][67]
Comparison for SaaS
|
Public cloud |
Private cloud |
Initial cost |
Typically zero |
Typically high |
Running cost |
Predictable |
Unpredictable |
Customization |
Impossible |
Possible |
Privacy |
No (Host has access to the data) |
Yes |
Single sign-on |
Impossible |
Possible |
Scaling up |
Easy while within defined limits |
Laborious but no limits |
Public cloud
A cloud is called a 'Public cloud' when the services are rendered
over a network that is open for public use. Technically there is no
difference between public and private cloud architecture, however,
security consideration may be substantially different for services
(applications, storage, and other resources) that are made available by
a service provider for a public audience and when communication is
effected over a non-trusted network. Generally, public cloud service
providers like Amazon AWS, Microsoft and Google own and operate the
infrastructure and offer access only via Internet (direct connectivity
is not offered).[31]
Community cloud shares infrastructure between several organizations
from a specific community with common concerns (security, compliance,
jurisdiction, etc.), whether managed internally or by a third-party and
hosted internally or externally. The costs are spread over fewer users
than a public cloud (but more than a private cloud), so only some of the
cost savings potential of cloud computing are realized.[2]
Hybrid cloud
Hybrid cloud is a composition of two or more clouds (private,
community or public) that remain unique entities but are bound together,
offering the benefits of multiple deployment models.[2]
Such composition expands deployment options for cloud services, allowing
IT organizations to use public cloud computing resources to meet
temporary needs.[68]
This capability enables hybrid clouds to employ cloud bursting for
scaling across clouds.[2]
Cloud bursting is an application deployment model in which an
application runs in a private cloud or data center and "bursts" to a
public cloud when the demand for computing capacity increases. A primary
advantage of cloud bursting and a hybrid cloud model is that an
organization only pays for extra compute resources when they are needed.[69]
Cloud bursting enables data centers to create an in-house IT
infrastructure that supports average workloads, and use cloud resources
from public or private clouds, during spikes in processing demands.[70]
By utilizing "hybrid cloud" architecture, companies and individuals
are able to obtain degrees of fault tolerance combined with locally
immediate usability without dependency on internet connectivity. Hybrid
cloud architecture requires both on-premises resources and off-site
(remote) server-based cloud infrastructure.
Hybrid clouds lack the flexibility, security and certainty of
in-house applications.[71]
Hybrid cloud provides the flexibility of in house applications with the
fault tolerance and scalability of cloud based services.
Architecture
Cloud computing sample architecture
Cloud architecture,[72]
the
systems architecture of the
software systems involved in the delivery of cloud computing,
typically involves multiple cloud components communicating with
each other over a loose coupling mechanism such as a messaging queue.
Elastic provision implies intelligence in the use of tight or loose
coupling as applied to mechanisms such as these and others.
The Intercloud
The Intercloud[73]
is an interconnected global "cloud of clouds"[74][75]
and an extension of the Internet "network of networks" on which it is
based.[76][77][78]
Cloud engineering
Cloud engineering is the application of
engineering disciplines to cloud computing. It brings a systematic
approach to the high-level concerns of commercialisation,
standardisation, and governance in conceiving, developing, operating and
maintaining cloud computing systems. It is a multidisciplinary method
encompassing contributions from diverse areas such as
systems,
software,
web,
performance,
information,
security,
platform,
risk, and
quality engineering.
Issues
Threats and opportunities of the cloud
Critical voices including
GNU project
initiator
Richard Stallman and
Oracle
founder
Larry Ellison warned that the whole concept is rife with privacy and
ownership concerns and constitute merely a fad.[79]
However, cloud computing continues to gain steam[80]
with 56% of the major European technology decision-makers estimate that
the cloud is a priority in 2013 and 2014, and the cloud budget may reach
30% of the overall IT budget.[citation
needed][81]
According to the TechInsights Report 2013: Cloud Succeeds
based on a survey, the cloud implementations generally meets or exceedes
expectations across major service models, such as Infrastructure as a
Service (IaaS), Platform as a Service (PaaS) and Software as a Service
(SaaS)".[82]
Several deterrents to the widespread adoption of cloud computing
remain. Among them, are: reliability, availability of services and data,
security, complexity, costs, regulations and legal issues, performance,
migration, reversion, the lack of standards, limited customization and
issues of privacy. The cloud offers many strong points:
infrastructure flexibility, faster deployment of applications and data,
cost control, adaptation of cloud resources to real needs, improved
productivity, etc. The early 2010s cloud market is dominated by software
and services in SaaS mode and IaaS (infrastructure), especially the
private cloud. PaaS and the public cloud are further back.
Privacy
Privacy advocates have criticized the cloud model for giving hosting
companies' greater ease to control—and thus, to monitor at
will—communication between host company and end user, and access user
data (with or without permission). Instances such as the
secret NSA program, working with
AT&T,
and
Verizon, which recorded over 10 million telephone calls between
American citizens, causes uncertainty among privacy advocates, and the
greater powers it gives to telecommunication companies to monitor user
activity.[83][84]
A cloud service provider (CSP) can complicate data privacy because of
the extent of virtualization (virtual machines) and
cloud storage used to implement cloud service.[85]
CSP operations, customer or tenant data may not remain on the same
system, or in the same data center or even within the same provider's
cloud; this can lead to legal concerns over jurisdiction. While there
have been efforts (such as
US-EU Safe Harbor) to "harmonise" the legal environment, providers
such as Amazon still cater to major markets (typically the United States
and the
European Union) by deploying local infrastructure and allowing
customers to select "availability zones."[86]
Cloud computing poses privacy concerns because the service provider may
access the data that is on the cloud at any point in time. They could
accidentally or deliberately alter or even delete information.[87]
Postage and delivery services company
Pitney Bowes launched Volly, a cloud-based, digital mailbox service
to leverage its communication management assets. They also faced the
technical challenge of providing strong data security and privacy.
However, they were able to address the same concern by applying
customized, application-level security, including encryption.[88]
Compliance
To comply with regulations including
FISMA,
HIPAA, and
SOX in the United States, the
Data Protection Directive in the EU and the credit card industry's
PCI DSS, users may have to adopt community or hybrid
deployment modes that are typically more expensive and may offer
restricted benefits. This is how
Google
is able to "manage and meet additional government policy requirements
beyond FISMA"[89][90]
and Rackspace Cloud or QubeSpace are able to claim PCI compliance.[91]
Many providers also obtain a
SAS 70 Type II audit, but this has been criticised on the grounds
that the hand-picked set of goals and standards determined by the
auditor and the auditee are often not disclosed and can vary widely.[92]
Providers typically make this information available on request, under
non-disclosure agreement.[93][94]
Customers in the EU contracting with cloud providers outside the
EU/EEA have to adhere to the EU regulations on export of personal data.[95]
U.S. Federal Agencies have been directed by the Office of Management
and Budget to use a process called FedRAMP (Federal Risk and
Authorization Management Program) to assess and authorize cloud products
and services. Federal CIO Steven VanRoekel issued a memorandum to
federal agency Chief Information Officers on December 8, 2011 defining
how federal agencies should use FedRAMP. FedRAMP consists of a subset of
NIST Special Publication 800-53 security controls specifically selected
to provide protection in cloud environments. A subset has been defined
for the FIPS 199 low categorization and the FIPS 199 moderate
categorization. The FedRAMP program has also established a Joint
Accreditation Board (JAB) consisting of Chief Information Officers from
DoD, DHS and GSA. The JAB is responsible for establishing accreditation
standards for 3rd party organizations who perform the assessments of
cloud solutions. The JAB also reviews authorization packages, and may
grant provisional authorization (to operate). The federal agency
consuming the service still has final responsibility for final authority
to operate.[96]
A multitude of laws and regulations have forced specific compliance
requirements onto many companies that collect, generate or store data.
These policies may dictate a wide array of data storage policies, such
as how long information must be retained, the process used for deleting
data, and even certain recovery plans. Below are some examples of
compliance laws or regulations.
- In the United States, the Health Insurance Portability and
Accountability Act (HIPAA) requires a contingency plan that
includes, data backups, data recovery, and data access during
emergencies.
- The privacy laws of the Switzerland demand that private data,
including emails, be physically stored in the Switzerland.
- In the United Kingdom, the Civil Contingencies Act of 2004 sets
forth guidance for a Business contingency plan that includes
policies for data storage.
In a virtualized cloud computing environment, customers may never
know exactly where their data is stored. In fact, data may be stored
across multiple data centers in an effort to improve reliability,
increase performance, and provide redundancies. This geographic
dispersion may make it more difficult to ascertain legal jurisdiction if
disputes arise.[97]
Legal
As with other changes in the landscape of computing, certain legal
issues arise with cloud computing, including trademark infringement,
security concerns and sharing of proprietary data resources.
The
Electronic Frontier Foundation has criticized the
United States government for considering during the
Megaupload seizure process that people lose
property rights by storing data on a cloud computing service.[98]
One important but not often mentioned problem with cloud computing is
the problem of who is in "possession" of the data. If a cloud company is
the possessor of the data, the possessor has certain legal rights. If
the cloud company is the "custodian" of the data, then a different set
of rights would apply. The next problem in the legalities of cloud
computing is the problem of legal ownership of the data. Many Terms of
Service agreements are silent on the question of ownership.[99]
These legal issues are not confined to the time period in which the
cloud based application is actively being used. There must also be
consideration for what happens when the provider-customer relationship
ends. In most cases, this event will be addressed before an application
is deployed to the cloud. However, in the case of provider insolvencies
or bankruptcy the state of the data may become blurred.[97]
Vendor lock-in
Because cloud computing is still relatively new, standards are still
being developed.[100]
Many cloud platforms and services are proprietary, meaning that they are
built on the specific standards, tools and protocols developed by a
particular vendor for its particular cloud offering.[100]
This can make migrating off a proprietary cloud platform prohibitively
complicated and expensive.[100]
Three types of vendor lock-in can occur with cloud computing:[101]
- Platform lock-in: cloud services tend to be built on one of
several possible virtualization platforms, for example VMWare or
Xen. Migrating from a cloud provider using one platform to a cloud
provider using a different platform could be very complicated.
- Data lock-in: since the cloud is still new, standards of
ownership, i.e. who actually owns the data once it lives on a cloud
platform, are not yet developed, which could make it complicated if
cloud computing users ever decide to move data off of a cloud
vendor's platform.
- Tools lock-in: if tools built to manage a cloud environment are
not compatible with different kinds of both virtual and physical
infrastructure, those tools will only be able to manage data or apps
that live in the vendor's particular cloud environment.
Heterogeneous cloud computing is described as a type of cloud
environment that prevents vendor lock-in, and aligns with enterprise
data centers that are operating hybrid cloud models.[102]
The absence of vendor lock-in lets cloud administrators select his or
her choice of hypervisors for specific tasks, or to deploy virtualized
infrastructures to other enterprises without the need to consider the
flavor of hypervisor in the other enterprise.[103]
A heterogeneous cloud is considered one that includes on-premise
private clouds, public clouds and software-as-a-service clouds.
Heterogeneous clouds can work with environments that are not
virtualized, such as traditional data centers.[104]
Heterogeneous clouds also allow for the use of piece parts, such as
hypervisors, servers, and storage, from multiple vendors.[105]
Cloud piece parts, such as cloud storage systems, offer APIs but they
are often incompatible with each other.[106]
The result is complicated migration between backends, and makes it
difficult to integrate data spread across various locations.[106]
This has been described as a problem of vendor lock-in.[106]
The solution to this is for clouds to adopt common standards.[106]
Heterogeneous cloud computing differs from homogeneous clouds, which
have been described as those using consistent building blocks supplied
by a single vendor.[107]
Intel General Manager of high-density computing, Jason Waxman, is quoted
as saying that a homogenous system of 15,000 servers would cost $6
million more in capital expenditure and use 1 megawatt of power.[107]
Open source
Open-source software has provided the foundation for many cloud
computing implementations, prominent examples being the
Hadoop framework[108]
and VMware's
Cloud Foundry.[109]
In November 2007, the
Free Software Foundation released the
Affero General Public License, a version of
GPLv3 intended to close a perceived
legal loophole associated with
free software designed to run over a network.[110]
Open standards
Most cloud providers expose APIs that are typically well-documented
(often under a
Creative Commons license[111])
but also unique to their implementation and thus not interoperable. Some
vendors have adopted others' APIs and there are a number of open
standards under development, with a view to delivering interoperability
and portability.[112]
As of November 2012, the Open Standard with broadest industry support is
probably
OpenStack, founded in 2010 by
NASA and
Rackspace, and now governed by the OpenStack Foundation.[113]
OpenStack supporters include
AMD,
Intel,
Canonical,
SUSE Linux,
Red Hat,
Cisco, Dell,
HP, IBM,
Yahoo and now
VMware.[114]
Security
As cloud computing is achieving increased popularity, concerns are
being voiced about the security issues introduced through adoption of
this new model.[1]
The effectiveness and efficiency of traditional protection mechanisms
are being reconsidered as the characteristics of this innovative
deployment model can differ widely from those of traditional
architectures.[115]
An alternative perspective on the topic of cloud security is that this
is but another, although quite broad, case of "applied security" and
that similar security principles that apply in shared multi-user
mainframe security models apply with cloud security.[116]
The relative security of cloud computing services is a contentious
issue that may be delaying its adoption.[117]
Physical control of the Private Cloud equipment is more secure than
having the equipment off site and under someone else's control. Physical
control and the ability to visually inspect data links and access ports
is required in order to ensure data links are not compromised. Issues
barring the adoption of cloud computing are due in large part to the
private and public sectors' unease surrounding the external management
of security-based services. It is the very nature of cloud
computing-based services, private or public, that promote external
management of provided services. This delivers great incentive to cloud
computing service providers to prioritize building and maintaining
strong management of secure services.[118]
Security issues have been categorised into sensitive data access, data
segregation, privacy, bug exploitation, recovery, accountability,
malicious insiders, management console security, account control, and
multi-tenancy issues. Solutions to various cloud security issues vary,
from cryptography, particularly public key infrastructure (PKI), to use
of multiple cloud providers, standardisation of APIs, and improving
virtual machine support and legal support.[115][119][120]
Cloud computing offers many benefits, but is vulnerable to threats.
As cloud computing uses increase, it is likely that more criminals find
new ways to exploit system vulnerabilities. Many underlying challenges
and risks in cloud computing increase the threat of data compromise. To
mitigate the threat, cloud computing stakeholders should invest heavily
in risk assessment to ensure that the system encrypts to protect data,
establishes trusted foundation to secure the platform and
infrastructure, and builds higher assurance into auditing to strengthen
compliance. Security concerns must be addressed to maintain trust in
cloud computing technology.[1]
Sustainability
Although cloud computing is often assumed to be a form of
green computing, no published study substantiates this
assumption.[121]
Citing the servers' effects on the environmental effects of cloud
computing, in areas where climate favors natural cooling and renewable
electricity is readily available, the environmental effects will be more
moderate. (The same holds true for "traditional" data centers.) Thus
countries with favorable conditions, such as Finland,[122]
Sweden and Switzerland,[123]
are trying to attract cloud computing data centers. Energy efficiency in
cloud computing can result from energy-aware
scheduling and server consolidation.[124]
However, in the case of distributed clouds over data centers with
different source of energies including renewable source of energies, a
small compromise on energy consumption reduction could result in high
carbon footprint reduction.[125]
Abuse
As with privately purchased hardware, customers can purchase the
services of cloud computing for nefarious purposes. This includes
password cracking and launching attacks using the purchased services.[126]
In 2009, a banking
trojan illegally used the popular Amazon service as a command and
control channel that issued software updates and malicious instructions
to PCs that were infected by the malware.[127]
IT governance
The introduction of cloud computing requires an appropriate IT
governance model to ensure a secured computing environment and to comply
with all relevant organizational information technology policies.[128][129]
As such, organizations need a set of capabilities that are essential
when effectively implementing and managing cloud services, including
demand management, relationship management, data security management,
application lifecycle management, risk and compliance management.[130]
A danger lies with the explosion of companies joining the growth in
cloud computing by becoming providers. However, many of the
infrastructural and logistical concerns regarding the operation of cloud
computing businesses are still unknown. This over-saturation may have
ramifications for the industry as whole.[131]
Consumer end
storage
The increased use of cloud computing could lead to a reduction in
demand for high storage capacity consumer end devices, due to cheaper
low storage devices that stream all content via the cloud becoming more
popular.[citation
needed] In a Wired article, Jake Gardner explains
that while unregulated usage is beneficial for IT and tech moguls like
Amazon, the anonymous nature of the cost of consumption of cloud usage
makes it difficult for business to evaluate and incorporate it into
their business plans.[131]
The popularity of cloud and cloud computing in general is so quickly
increasing among all sorts of companies, that in May 2013, through its
company Amazon Web Services,
Amazon started a certification program for cloud computing
professionals.
Ambiguity of
terminology
Outside of the information technology and software industry, the term
"cloud" can be found to reference a wide range of services, some of
which fall under the category of cloud computing, while others do not.
The cloud is often used to refer to a product or service that is
discovered, accessed and paid for over the Internet, but is not
necessarily a computing resource. Examples of service that are sometimes
referred to as "the cloud" include, but are not limited to,
crowd sourcing,
cloud printing,
crowd funding,
cloud manufacturing.[132][133]
Performance interference and noisy neighbors
Due to its multi-tenant nature and resource sharing, Cloud computing
must also deal with the "noisy neighbor" effect. This effect in essence
indicates that in a shared infrastructure, the activity of a virtual
machine on a neighboring core on the same physical host may lead to
increased performance degradation of the VMs in the same physical host,
due to issues such as e.g. cache contamination. Due to the fact that the
neighboring VMs may be activated or deactivated at arbitrary times, the
result is an increased variation in the actual performance of Cloud
resources. This effect seems to be dependent also on the nature of the
applications that run inside the VMs but also other factors such as
scheduling parameters and the careful selection may lead to optimized
assignment in order to minimize the phenomenon.[134]
Research
Many universities, vendors, Institutes and government organizations
are investing in research around the topic of cloud computing:[135][136]
- In October 2007, the Academic Cloud Computing Initiative (ACCI)
was announced as a multi-university project designed to enhance
students' technical knowledge to address the challenges of cloud
computing.[137]
- In April 2009, UC Santa Barbara released the first open source
platform-as-a-service,
AppScale, which is capable of running Google App Engine
applications at scale on a multitude of infrastructures.
- In April 2009, the St Andrews Cloud Computing Co-laboratory was
launched, focusing on research in the important new area of cloud
computing. Unique in the UK, StACC aims to become an international
centre of excellence for research and teaching in cloud computing
and provides advice and information to businesses interested in
cloud-based services.[138]
- In October 2010, the TClouds (Trustworthy Clouds) project was
started, funded by the European Commission's 7th Framework
Programme. The project's goal is to research and inspect the legal
foundation and architectural design to build a resilient and
trustworthy cloud-of-cloud infrastructure on top of that. The
project also develops a prototype to demonstrate its results.[139]
- In December 2010, the TrustCloud research project
[140][141]
was started by HP Labs Singapore to address transparency and
accountability of cloud computing via detective, data-centric
approaches[142]
encapsulated in a five-layer TrustCloud Framework. The team
identified the need for monitoring data life cycles and transfers in
the cloud,[140]
leading to the tackling of key cloud computing security issues such
as cloud data leakages, cloud accountability and cross-national data
transfers in transnational clouds.
- In July 2011, the High Performance Computing Cloud (HPCCLoud)
project was kicked-off aiming at finding out the possibilities of
enhancing performance on cloud environments while running the
scientific applications - development of HPCCLoud Performance
Analysis Toolkit which was funded by CIM-Returning Experts Programme
- under the coordination of Prof. Dr. Shajulin Benedict.
- In June 2011, the
Telecommunications Industry Association developed a Cloud
Computing White Paper, to analyze the integration challenges and
opportunities between cloud services and traditional U.S.
telecommunications standards.[144]
- In December 2012, a study released by Microsoft and the
International Data Corporation (IDC)showed that
millions of cloud-skilled workers would be needed. Millions of
cloud-related IT jobs are sitting open and millions more will open
in the coming couple of years, due to a shortage in cloud-certified
IT workers.
- In February 2013, the BonFIRE project launched a multi-site
cloud experimentation and testing facility. The facility provides
transparent access to cloud resources, with the control and
observability necessary to engineer future cloud technologies, in a
way that is not restricted, for example, by current business models.[145]
- In April 2013, A 2013 report by IT research and advisory firm
Gartner., Inc. says that
app developers will embrace cloud services, predicting that in
three years, 40% of the mobile app development projects will use
cloud backed services. Cloud mobile backed services offer a new kind
of PaaS, used to enable the development of mobile apps.
Early references in popular culture
In the 1966
Star Trek episode
"Miri,"
Dr. McCoy, while stationed planetside, uses the computer of the
orbiting
Enterprise to process the data gathered by his portable equipment.
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Security Technologies of the Committee on Homeland Security, House
of Representatives, One Hundred Twelfth Congress, First Session,
October 6, 2011
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Cloud Computing represents both a significant opportunity and a
potential challenge
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