Cloud computing is a colloquial expression used to describe a variety of different types of computing concepts that involve a large number of computers connectedthrough a real-time communication network (typically the Internet).
Cloud computing is a jargon term[citation needed] 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 connectedcomputers at the same time. The phrase is also, more commonly used to refer to network based services which appear to be providedby real server hardware, which in fact are served up by virtual hardware, simulated by software running on one or more real machines.
Such virtual servers do not physically exist and can therefore be moved around and scaled up (or down) on the fly without affectingthe end user - arguably, rather like a cloud.
The popularity of the term can be attributed to its use in marketing to sell hosted services in the sense of applicationservice provisioning that run client server software on a remote location.
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.At the foundation of cloud computing is the broader concept of converged infrastructure and shared services.
In science, cloud computing is a synonym for distributed computing over a network and means the ability to run a program on many connectedcomputers at the same time. The phrase is also, more commonly used to refer to network based services which appear to be providedby real server hardware, which in fact are served up by virtual hardware, simulated by software running on one or more real machines.
Such virtual servers do not physically exist and can therefore be moved around and scaled up (or down) on the fly without affectingthe end user - arguably, rather like a cloud.
The popularity of the term can be attributed to its use in marketing to sell hosted services in the sense of applicationservice provisioning that run client server software on a remote location.
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.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 dynamically re-allocated per demand.
This can work for allocating resources to users. 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 a variety of functions.
The term "moving to 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.
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.
The cloud also focuses on maximizing the effectiveness of the shared resources.
Cloud resources are usually not only shared by multiple users but as dynamically re-allocated per demand.
This can work for allocating resources to users. 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 a variety of functions.
The term "moving to 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.
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.
Service models
Cloud computing providers offer their services according to several fundamental models: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 anything as a service (XaaS) are described in a comprehensive taxonomy model published in 2009,[55] 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.
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.[57] 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: cost reflects the amount of resources allocated and consumed.Examples of IaaS providers include: Amazon EC2, Google Compute Engine, HP Cloud, Joyent, Linode, NaviSite, Rackspace,Windows Azure, ReadySpace Cloud Services, Terremark, and Internap Agile.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 so that the cloud user does not have to allocate resources manually.Examples of PaaS include: AWS Elastic Beanstalk, Cloud Foundry, Heroku, Force.com, Engine Yard, 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. 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, so price is scalable and adjustable if
users are added or removed at any point.
Examples of SaaS
include: Google Apps, Microsoft Office
365, Petrosoft, Onlive, GT
Nexus, Marketo, Casengo, TradeCard, Rally Software, Salesforce, ExactTarget 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. NaaS involves the optimization of
resource allocations by considering network and computing resources as a
unified whole.
Traditional NaaS
services include flexible and extended VPN, and bandwidth on demand. 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).
Cloud Management
Cloud management means the software and technologies designed for operating and monitoring applications, data and services residing in the cloud. Cloud management tools help ensure a company's cloud computing-based resources are working optimally and properly interacting with users and other services.
Cloud management strategies typically involve numerous tasks including performance monitoring (response times, latency, uptime, etc.), security and compliance auditing and management, and initiating and overseeing disaster recovery and contingency plans.
Types of Cloud Computing: Private, Public and Hybrid Clouds
With cloud computing growing more complex and a wide variety of private, hybrid, and public cloud-based systems and infrastructure already in use, a company’s collection of cloud management tools needs to be just as flexible and scalable as its cloud computing strategy.
With
cloud computing technology, large pools of resources can be connected through
private or public networks. This technology simplifies infrastructure planning
and provides dynamically scalable infrastructure for cloud based applications,
data, and file storage. Businesses can choose to deploy applications
on Public, Private, Hybrid clouds or the newer Community Cloud.
What are the differences between these types of cloud computing, and how can
you determine the right cloud path for your organization? Here are some
fundamentals of each to help with the decision-making process.
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Public
- Public clouds are made available to the general public by a service provider who hosts the cloud infrastructure. Generally, public cloud providers like Amazon AWS, Microsoft and Google own and operate the infrastructure and offer access over the Internet. With this model, customers have no visibility or control over where the infrastructure is located. It is important to note that all customers on public clouds share the same infrastructure pool with limited configuration, security protections and availability variances.
- Public Cloud customers benefit from economies of scale, because infrastructure costs are spread across all users, allowing each individual client to operate on a low-cost, “pay-as-you-go” model. Another advantage of public cloud infrastructures is that they are typically larger in scale than an in-house enterprise cloud, which provides clients with seamless, on-demand scalability. These clouds offer the greatest level of efficiency in shared resources; however, they are also more vulnerable than private clouds.
- A public cloud is the obvious choice when:
- Your standardized workload for applications is used by lots of people, such as e-mail.
- You need to test and develop application code.
- You need incremental capacity (the ability to add compute resources for peak times).
- You’re doing collaboration projects.
Private
Private
cloud is cloud infrastructure dedicated to a particular organization. Private
clouds allow businesses to host applications in the cloud, while addressing
concerns regarding data security and control, which is often lacking in a
public cloud environment. It is not shared with other organizations,
whether managed internally or by a third-party, and it can be hosted internally
or externally.
There
are two variations of private clouds:
1. On-Premise Private Cloud: This type of
cloud is hosted within an organization’s own facility. A businesses IT
department would incur the capital and operational costs for the physical
resources with this model. On-Premise Private Clouds are best used for applications
that require complete control and configurability of the infrastructure and
security.
2. Externally Hosted Private Cloud:
Externally hosted private clouds are also exclusively used by one organization,
but are hosted by a third party specializing in cloud infrastructure. The
service provider facilitates an exclusive cloud environment with full guarantee
of privacy. This format is recommended for organizations that prefer not to use
a public cloud infrastructure due to the risks associated with the sharing of
physical resources.
Undertaking
a private cloud project requires a significant level and degree of engagement
to virtualize the business environment, and it will require the organization to
reevaluate decisions about existing resources. Private clouds are more
expensive but also more secure when compared to public clouds. An Info-Tech
survey shows that 76% of IT decision-makers will focus exclusively on the
private cloud, as these clouds offer the greatest level of security and
control.
When
is a Private Cloud for you?
· You need data
sovereignty but want cloud efficiencies
· You want consistency
across services
· You have more server
capacity than your organization can use
· Your data center must
become more efficient
· You want to provide
private cloud services
Hybrid
- Hybrid Clouds are a composition of two or more clouds (private, community or public) that remain unique entities but are bound together offering the advantages of multiple deployment models. In a hybrid cloud, you can leverage third party cloud providers in either a full or partial manner; increasing the flexibility of computing. Augmenting a traditional private cloud with the resources of a public cloud can be used to manage any unexpected surges in workload.
- Hybrid cloud architecture requires both on-premise resources and off-site server based cloud infrastructure. By spreading things out over a hybrid cloud, you keep each aspect of your business in the most efficient environment possible. The downside is that you have to keep track of multiple cloud security platforms and ensure that all aspects of your business can communicate with each other.
- Here are a couple of situations where a hybrid environment is best:
- Your company wants to use a SaaS application but is concerned about security.
- Your company offers services that are tailored for different vertical markets. You can use a public cloud to interact with the clients but keep their data secured within a private cloud.
- You can provide public cloud to your customers while using a private cloud for internal IT.
Community
A
community cloud is a is a multi-tenant cloud service model that is shared among
several or organizations and that is governed, managed and secured commonly by
all the participating organizations or a third party managed service provider.
Community
clouds are a hybrid form of private clouds built and operated specifically for
a targeted group. These communities have similar cloud requirements and their
ultimate goal is to work together to achieve their business objectives.
The goal of community clouds is to have participating organizations realize the benefits of a public cloud with the added level of privacy, security, and policy compliance usually associated with a private cloud. Community clouds can be either on-premise or off-premise.
The goal of community clouds is to have participating organizations realize the benefits of a public cloud with the added level of privacy, security, and policy compliance usually associated with a private cloud. Community clouds can be either on-premise or off-premise.
Here
are a couple of situations where a community cloud environment is best:
· Government
organizations within a state that need to share resoures
· A private HIPAA
compliant cloud for a group of hospitals or clinics
· Telco community cloud
for telco DR to meet specific FCC regulations
Cloud
computing is about shared IT infrastructure or the outsourcing of a company's
technology. It is essential to examine your current IT infrastructure,
usage and needs to determine which type of cloud computing can help you best
achieve your goals. Simply, the cloud is not one concrete term, but
rather a metaphor for a global network and how to best utilize its advantages
depends on your individual cloud focus.
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