Cloud computing in general can be portrayed as a synonym for distributed computing over a network, with the ability to run a program or application on many connected computers at the same time. It specifically refers to a computing hardware machine or group of computing hardware machines commonly referred as a server connected through a communication network such as the Internet, an intranet, a local area network (LAN) or wide area network (WAN) and individual users or user who have permission to access the server can use the server's processing power for their individual computing needs like to run an application, store data or any other computing need. Therefore, instead of using a personal computer every-time to run the application, the individual can now run the application from anywhere in the world, as the server provides the processing power to the application and the server is also connected to a network via internet or other connection platforms to be accessed from anywhere . All this has become possible due to increasing computer processing power available to humankind with decrease in cost as stated in Moore's law.
In common
usage, the term "the cloud" is essentially a metaphor for the
Internet. Marketers have further popularized the phrase "in the
cloud" to refer to software, platforms and infrastructure that are sold
"as a service", i.e. remotely through the Internet. Typically, the
seller has actual energy-consuming servers which host products and services
from a remote location, so end-users don't have to; they can simply log on to
the network without installing anything. The major models of cloud computing
service are known as software as a service, platform as a service, and
infrastructure as a service. These cloud services may be offered in a public,
private or hybrid network. Google, Amazon, IBM, Oracle Cloud, Rackspace,
Salesforce, Zoho and Microsoft Azure are some well-known cloud vendors.
Network-based
services, which appear to be provided by real server hardware and are in fact
served up by virtual hardware simulated by software running on one or more real
machines, are often called cloud computing. Such virtual servers do not
physically exist and can therefore be moved around and scaled up or down on the
fly without affecting the end user, somewhat like a cloud becoming larger or
smaller without being a physical object.
Advantages
of cloud computing
2. More Storage.
In the past, memory was limited by the particular device in question. If you
ran out of memory, you would need a USB drive to backup your current device.
Cloud computing provides increased storage, so you won’t have to worry about
running out of space on your hard drive.
3. Easy Set-Up. You can set up a cloud computing
service in a matter of minutes. Adjusting your individual settings, such as
choosing a password or selecting which devices you want to connect to the
network, is similarly simple. After that, you can immediately start using the
resources, software, or information in question.
4. Automatic Updates. The cloud computing provider is
responsible for making sure that updates are available – you just have to
download them. This saves you time, and furthermore, you don’t need to be an
expert to update your device; the cloud computing provider will automatically
notify you and provide you with instructions.
5. Reduced Cost. Cloud computing is often
inexpensive. The software is already installed online, so you won’t need to
install it yourself. There are numerous cloud computing applications available
for free, such as Dropbox, and increasing storage size and memory is
affordable. If you need to pay for a cloud computing service, it is paid for
incrementally on a monthly or yearly basis. By choosing a plan that has no
contract, you can terminate your use of the services at any time; therefore,
you only pay for the services when you need them
The working
principle of cloud computing
The
principle of cloud computing is almost same with another computer, just
the different of that is in cloud computing, is coupled with another present
computer. In regular computer, file from software when we used is stored
in hardisk or another storage media. But on computer clouds if viewed from the
side of the user, the files from software we use is in another computer.
In other
words we are connected to multiple computers on a network server, but the data
we store it was in the data center or in center, so that not only we can open
the file that we save but computers or other users can open it and vice versa
(Public). Also in a lot of infrastructure servers that we can use and we only
pay as needed.
Characteristics
cloud computing
1. On-demand
self-service. This means provisioning or de-provisioning computing
resources as needed in an automated fashion without human intervention. An
analogy to this is electricity as a utility where a consumer can turn on or off
a switch on-demand to use as much electricity as required.
2.
Ubiquitous network access. This means that computing facilities can be
accessed from anywhere over the network using any sort of thin or thick clients
(for example smartphones, tablets, laptops, personal computers and so on).
3. Resource
pooling. This means that computing resources are pooled to meet the demand
of the consumers so that resources (physical or virtual) can be dynamically
assigned, reassigned or de-allocated as per the requirement. Generally the
consumers are not aware of the exact location of computing resources. However,
they may be able to specify location (country, city, region and the like) for
their need. For example, I as a consumer might want to host my services with a
cloud provider that has cloud data centers within the boundaries of Australia.
4. Rapid
elasticity. Cloud computing provides an illusion of infinite computing
resources to the users. In cloud models, resources can be elastically
provisioned or released according to demand. For example, my cloud-based online
services should be able to handle a sudden peak in traffic demand by expanding
the resources elastically. When the peak subsides, unnecessary resources can be
released automatically.
5. Measured
service. This means that consumers only pay for the computing resources
they have used. This concept is similar to utilities like water or electricity.
Security
Security.
When using a cloud computing service, you are essentially handing over your
data to a third party. The fact that the entity, as well as users from all over
the world, are accessing the same server can cause a security issue. Companies
handling confidential information might be particularly concerned about using
cloud computing, as data could possibly be harmed by viruses and other malware.
That said, some servers like Google Cloud Connect come with customizable spam
filtering, email encryption, and SSL enforcement for secure HTTPS access,
among other security measures.
The biggest
question most have with Cloud Computing is will it be Safe? The answer is “NO” Reason
why is everything that Cloud Computing is based on is mechanical, although it
seems virtual. The Safety of the data (information), is only as Safe as the
will and determination of the individual that wants to have at it.
The Concept
of Cloud Computing
The first
building block is the infrastructure where the cloud will be implemented. Some
people make the assumption that environment should be virtualized, but as cloud
is a way to request resources in an on-demand way and if you have solutions to
provide on bare metal, then why not? The infrastructure will support the
different types of cloud (IaaS, PaaS, SaaS, BPaaS).
To be able
to provide these services you will need Operating System Services (OSS), which
will be in charge of deploying the requested service, and Business System
Services (BSS), mainly used to validate the request and create the invoice for
the requested services. Any metrics could be used to create the invoice (for
example, number of users, number of CPUs, memory, usage hours/month). It is
very flexible and depends on the service provider.
A cloud
computing environment will also need to provide interfaces and tools for the
service creators and users. This is the role of the Cloud Service Creator and
Cloud Service Consumer components.
Now, let’s
see how it works in reality.
Generally,
you log in to a portal (enterprise or public wise) and you order your services
through the Cloud Service Consumer. This service has been created by the cloud
service provider and can be a simple virtual machine (VM) based on an image,
some network components, an application service such as an WebApp environment
and a service such as MongoDB. It depends on the provider and type of resources
and services.
The cloud
provider will validate, through the BSS, your request and if the validation is
okay (credit card, contract), it will provision the request through the OSS.
You will
receive, in one way or another, the credentials to access your requested
services and you will usually receive a monthly invoice for your consumption.
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,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 OpenStack, Xen, KVM, VMware ESX/ESXi, or Hyper-V 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. 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.
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
models, 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 like Windows
Azure, the underlying computer and storage resources scale automatically to
match application demand so that the cloud user does not have to allocate
resources manually. The latter has also been proposed by an architecture aiming
to facilitate real-time in cloud environments.
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.
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. For this reason, users are
increasingly adopting intelligent third-party key management systems to help
secure their data.
Security as
a service (SECaaS)
Security as
a service (SECaaS) is a business model in which a large service provider
integrates their security services into a corporate infrastructure on a
subscription basis more cost effectively than most individuals or corporations
can provide on their own, when total cost of ownership is considered. These
security services often include authentication, anti-virus,
anti-malware/spyware, intrusion detection, and security event management, among
others
Reference :
http://en.wikipedia.org/wiki/Cloud_computing
http://thoughtsoncloud.com/2014/02/how-does-cloud-computing-work/
http://thoughtsoncloud.com/2014/02/cloud-computing-basics/
http://www.dummies.com/how-to/content/what-is-cloud-computing.html
http://www.wikinvest.com/concept/Cloud_Computing
http://www.webopedia.com/TERM/C/cloud_computing.html
http://12285-if-unsika.blogspot.com/2012/10/prinsip-kerja-cloud-computing-atau.html
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