Cloud Computing Essay
ABSTRACT: This white paper is an introduction to the terms, characteristics, and services associated with internet-based computing, commonly referred to as cloud computing. Also introduced are the benefits and challenges associated with cloud computing, and for those seeking to use communications services in the cloud, briefly presented are different ways of determining the interfaces needed to use these communications services. Cloud computing is where software applications, processing power, data and potentially even artificial intelligence are accessed over the Internet. Many private individuals now regularly use an online email application such as Gmail, Yahoo! Mail or Hotmail.
The location of physical resources and devices being accessed are typically not known to the end user. It also provides facilities for users to develop, deploy and manage their applications ‘on the cloud’, which entails virtualization of resources that maintains and manages itself.
1. What is Cloud Computing?
Cloud computing provides the facility to access shared resources and common infrastructure, offering services n demand over the network to perform operations that meet changing business needs.
“Cloud computing is a general term for anything that involves delivering hosted services over the internet.” – Wikipedia “Cloud computing is Internet-based computing, whereby shared resources, software, and information are provided to computers and other devices on demand, like the electricity grid.”- Wikipedia Basically a cloud is a virtualization of Resources that manages and maintains itself.
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2. Types of cloud
Public Cloud: the services are delivered to the client via the Internet from a third party service provider. Example: Amazon, Yahoo, Google
Example of Clouds
Cloud architecture, the systems architecture of the software systems involved in the delivery of cloud computing, typically involves multiple cloud components communicating with each other over application programming interfaces, usually web services and 3-tier architecture. This resembles the Unix philosophy of having multiple programs each doing one thing well and working together over universal interfaces. Complexity is controlled and the resulting systems are more manageable than their monolithic counterparts.
Private Cloud: these services are managed and provided within the organization. There are less restriction on network bandwidth, fewer security exposures and other legal requirements compared to the public Cloud. Example: HP Data Centers Hybrid cloud: There is some confusion over the term “Hybrid” when applied to the cloud – a standard definition of the term “Hybrid Cloud” has not yet emerged. The term “Hybrid Cloud” has been used to mean either two separate clouds joined together (public, private, internal or external), or a combination of virtualized cloud server instances used together with real physical hardware. The most correct definition of the term “Hybrid Cloud” is probably the use of physical hardware and virtualized cloud server instances together to provide a single common service
The two most significant components of cloud computing architecture are known as the front end and the back end. The front end is the part seen by the client, i.e. the computer user.
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This includes the client’s network (or computer) and the applications used to access the cloud via a user interface such as a web browser. The back end of the cloud computing architecture is the ‘cloud’ itself, comprising various computers, servers and data storage devices
collaboration. For more information on collaborative working using Google Docs, you can watch the now classic video Google Docs in Plain English. Taking collaboration further still, the outputs of some SaaS applications can be embedded in other web pages as web service gadgets. For example, a Google Docs or Zoho Sheet chart can be mashed into another website.
There it will automatically update when the data in the online spreadsheet that is generating it is changed. SaaS applications are also constantly updated, which can free users of the “upgrade hell” of a major traditional software package revision. The disadvantage of SaaS is that it is basically a takeit-or-leave-it form of cloud computing. This means that businesses and individuals who require direct access to cloud computing hardware on which they can run their own applications cannot use SaaS. Rather, they need to cloud compute at the platform or infrastructure level using either platform as a service (PaaS) or infrastructure as a service (IaaS).
4. Services of Cloud Computing
SaaS(Software as a Service) PaaS(Platform as a Service) IaaS(Infrastructure as a Service)
Services Of Cloud computing
PaaS(Platform as a Service)
A platform is a software environment used to develop and run applications. For example, Microsoft Word is an application that runs on the Microsoft Windows platform. When people choose to cloud compute using platform as a service or ‘PaaS’, they obtain access to an online platform provided by a cloud computing vendor. They can then use this platform to develop and deliver their own online (SaaS) applications. Applications developed using PaaS may be used privately by just one or a few users within a particular company.
However, they can also be offered free or for-a-fee to anybody on the web. This means that if you have a great idea for a new online application then you can use PaaS to turn it into a reality! Several cloud suppliers now offer PaaS tools. Most notably these include Google App Engine, Microsoft Windows Azure, and Force.com. All such offerings effectively provide their customers with a box of cloud computing Lego. New applications are then constructed from the plastic bricks on offer. With Force.com, some applications can even be built using a simple drag-and-drop interface. Relatively nontechnical people can therefore create new online applications very quickly.
SaaS (Software as a Service)
Software as a service is where computer applications are accessed over the Internet rather than being installed on a local computing device or in a local data centre. So, for example, people may use an online word processor like Google Docs, an online database application like Zoho Creator, an online photo editor like Pixar, or an online invoicing application such as Zoho Invoice. Many SaaS applications are free to use, at least initially. You can find links to a great many in the Cloud Computing Directory. SaaS can provide its users with many benefits.
These include the general cloud computing advantages of dynamic scalability and any device independence, as well as the benefit of being able to use an application without incurring fixed costs. Many SaaS applications are also collaborative. This allows multiple users to share documents and even to work on them at the same time. For example, in the Google Docs spreadsheet different users can work on different cells simultaneously. The cells different users are working on are locked-off and highlighted in different colours. A real-time chat window can also be opened up alongside the spreadsheet to further enhance
Indeed, Force.com claim that their “simplified programming model and cloud-based environment mean [customers] can build and run applications five times faster, at about half the cost of traditional software platforms”. Google App Engine and Force.com also allow an initial application to be created for free! Whilst PaaS is great in many situations, its users do need to be mindful of the involved flexibility verses power trade-off. What this means is that whilst PaaS makes it relatively easy to create new online applications, users are nevertheless constrained by the particular programming languages and tools provided by their PaaS supplier. In other words, PaaS vendors have total control over which Lego bricks they allow their customers to build with. Whilst this ensures that applications built using the tools on offer will always function correctly, it is nevertheless restrictive. It is for this reason that many companies and some individuals choose to cloud compute at the infrastructure level.
Dedicated physical servers and virtual server instances can perform exactly the same functions. However, there are some differences between them. For a start, virtual server instances are cheaper to supply as each does not require its own piece of physical hardware in a cloud data centre. On the other hand, virtual server instances are sometimes seen as less secure by those who do not want to share server hardware with other customers. For this reason, four categories of IaaS are available. These are most commonly known as “private clouds”, “dedicated hosting”, “hybrid hosting” and “cloud hosting”.
5. How cloud computing works?
In traditional enterprise computing, IT departments forecast demand for applications and capacity and invest time and money to develop those resources inhouse or purchase them from others and operate them in-house.
IaaS (Infrastructure as a Service)
Infrastructure as a service or “IaaS” is where a cloud supplier provides online infrastructure on which their customers can store data and develop and run whatever applications they please. IaaS therefore allows companies to move their existing programs and data into the cloud and to close down their own local servers and data centres. Whilst computing applications run on platforms, platforms in turn run on computing infrastructure. So, for example, whilst the Microsoft Word application runs on the Microsoft Windows platform, in turn the Microsoft Windows platform runs on the infrastructure of an IBM-compatible PC.
How it works
The fundamental building block of cloud computing infrastructure is the server. Cloud computing servers are basically computers on which online applications can be run and data can be stored. When provided by an IaaS vendor, cloud servers can also be real or virtual. Real or “dedicated” servers are individual circuit boards – known as blades – mounted within equipment racks in a data centre. In contrast virtual servers – also known as “virtual server instances” – are software-controlled slices of real, physical servers.
Virtual servers are created by a process called virtualization that allows many users to share the processing power of one physical server. With cloud computing, institutions procure IT services from remote providers, and campus constituents access these resources over the Internet. E-mail, for example, long considered a staple of an institution’s IT operations, can be obtained from a range of sources, and a growing number of campuses contract with outside suppliers for this function. Software is hosted by the provider and does not need to be installed—or maintained—on individual computers around campus.
In some cases, a large university or a consortium might become a provider of cloud services. Storage and processing needs can also be met by the cloud. Institutions pay only for the resources used, and users can access the applications and files they need from virtually any Internet- connected computer. In a mature cloud computing environment, institutions would be able to add new IT services or respond to changes in capacity on the fly, saving capital costs that can be redirected to programs of strategic value to the institution.
• • • • • • • • • Reduced Hardware equipment for end users Improved Performance Lower Hardware and Software Maintenance Instant Software Updates Accessibility Less Expensive (Amazon example) Better Collaboration Pay for what you use Flexible
• High scalability
Cloud environments enable servicing of business requirements for larger audiences, through high scalability
• • • • • • Security Issues (#1 concern) Internet connection Too many platforms Location of Servers Time for Transition Speed
The cloud works in the ‘distributed mode’ environment. It shares resources among users and tasks, while improving efficiency and agility (responsiveness) • High availability and reliability Availability of servers is high and more reliable as the chances of infrastructure failure are minimal • Multi-sharing With the cloud working in a distributed and shared mode, multiple users and applications can work more efficiently with cost Reductions by sharing common infrastructure • Services in pay-per-use mode SLAs between the provider and the user must be defined when offering
services in pay per use mode. This may be based on the complexity of services offered Application Programming Interfaces (APIs) may be offered to the users so they can access services on the cloud by using these APIs
After so many years, Cloud Computing today is the beginning of “network based computing” over Internet in force. It is the technology of the decade and is the enabling element of two totally new computing models, the Client-Cloud computing and the Terminal-Cloud computing. These new models would create whole generations of applications and business. Our prediction is that it is the beginning to the end of the dominance of desktop computing such as that with the Windows. It is also the beginning of a new Internet based service economy: the Internet centric, Web based, on demand, Cloud applications and computing economy
University/College: University of Arkansas System
Type of paper: Thesis/Dissertation Chapter
Date: 17 October 2016
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