Cloud Computing: An Overview Bhanu Jallandhra Manpreet Singh Bajwa (8CS20) (8CS41) Abstract--Cloud Computing as an Internet-based computing; When a Cloud is made available in a pay-as-you-go where resources, software and information are provided to manner to the public, we call it a Public Cloud; the service computers on-demand, like a public utility; is emerging as a being sold is Utility Computing. Current examples of platform for sharing resources like infrastructure, software public Utility Computing include AmazonWeb Services, and various applications. The majority of cloud computing Google AppEngine, and Microsoft Azure. We use the term infrastructure consists of reliable services delivered through Private Cloud to refer to internal datacenters of a business data centres and built on servers and the prominent applications of Cloud Computing, and how they meet the or other organization that are not made available to the requirements of reliability, availability of data, and scalability public. Thus, Cloud Computing is the sum of SaaS and of software. Utility Computing, but does not normally include Private Clouds. We’ll generally use Cloud Computing, replacing it Keywords: with one of the other terms only when clarity demands it. Cloud computing, SaaS, PaaS, IaaS, network cloud, data Figure 1 shows the roles of the people as users or center providers of these layers of Cloud Computing, and we’ll use those terms to help make our arguments clear. 1. INTRODUCTION The advantages of SaaS to both end users and service providers are well understood. Service providers enjoy As a metaphor for the Internet, "the cloud" is a familiar greatly simplified software installation and maintenance cliché, but when combined with "computing", the meaning and centralized control over versioning; end users can gets bigger and fuzzier. Some analysts and vendors define access the service “anytime, anywhere”, share data and cloud computing narrowly as an updated version of utility collaborate more easily, and keep their data stored safely in computing: basically virtual servers available over the the infrastructure. Internet. Others go very broad, arguing anything you consume outside the firewall is "in the cloud", including Cloud Computing does not change these arguments, but it conventional outsourcing. does give more application providers the choice of deploying their product as SaaS without provisioning a Cloud computing comes into focus only when you think data center: just as the emergence of semiconductor about what we always need: a way to increase capacity or foundries gave chip companies the opportunity to design add capabilities on the fly without investing in new and sell chips without owning a fab, Cloud Computing infrastructure, training new personnel, or licensing new allows deploying SaaS—and scaling on demand—without software. Cloud computing encompasses any subscription- building or provisioning a data center. based or pay-per-use service that, in real time over the Internet, extends ICT's existing capabilities. Analogously to how SaaS allows the user to offload some problems to the SaaS provider, the SaaS provider can now Cloud computing is at an early stage, with a motley crew offload some of his problems to the Cloud Computing of providers large and small delivering a slew of cloud- provider. From now on, we will focus on issues related to based services, from full-blown applications to storage the potential SaaS Provider (Cloud User) and to the Cloud services to spam filtering. Yes, utility-style infrastructure Providers, which have received less attention. providers are part of the mix, but so are SaaS (software as From a hardware point of view, three aspects are new in a service) providers such as Salesforce.com. Today, for the Cloud Computing: most part, IT must plug into cloud-based services individually, but cloud computing aggregators and I. The illusion of infinite computing resources available integrators are already emerging. on demand, thereby eliminating the need for Cloud Computing users to plan far ahead for provisioning; 2. THE CONCEPT II. The elimination of an up-front commitment by Cloud Cloud Computing refers to both the applications delivered users, thereby allowing companies to start small and as services over the Internet and the hardware and systems increase hardware resources only when there is an software in the data centres that provide those services. increase in their needs; The services themselves have long been referred to as Software as a Service (SaaS), so we use that term. The III. The ability to pay for use of computing resources on a datacentre hardware and software is what we will call a short-term basis as needed (e.g., processors by the hour Cloud. and storage by the day) and release them as needed, P a g e | 1 thereby rewarding conservation by letting machines Amazon.com played a key role in the development of and storage go when they are no longer useful. cloud computing by modernizing their data centers after the dot-com bubble and, having found that the new cloud architecture resulted in significant internal efficiency improvements, providing access to their systems by way of Amazon Web Services in 2005 on a utility computing basis. 2007 saw increased activity, with Google, IBM, and a number of universities embarking on a large scale cloud computing research project, around the time the term started gaining popularity in the mainstream press. It was a hot topic by mid-2008 and numerous cloud computing events had been scheduled. In August 2008, Gartner Research observed that "organizations are switching from company-owned Figure 1: Users and Providers of Cloud Computing. The benefits hardware and software assets to per-use service-based of SaaS to both SaaS users and SaaS providers are well models" and that the "projected shift to cloud computing documented, so we focus on Cloud Computing’s effects on Cloud will result in dramatic growth in IT products in some areas Providers and SaaS Providers/Cloud users. The top level can be and in significant reductions in other areas." [1] recursive, in that SaaS providers can also be a SaaS users. 4. IMPLEMENTATION 3. HISTORY Adopting cloud computing services is a process that must The Cloud is a term with a long history in telephony, which be carefully planned and executed in order for an has in the past decade, been adopted as a metaphor for organization to experience the best possible return on internet based services, with a common depiction in investment and use of the technology. network diagrams as a cloud outline. Below are a few steps that all companies must take along The underlying concept dates back to 1960 when John the way: McCarthy opined that "computation may someday be organized as a public utility"; indeed it shares I. Recognize the need for integration solutions: characteristics with service bureaus which date back to the 1960s. The term cloud had already come into commercial While the technology may be different, the process for use in the early 1990s to refer to large ATM networks. By implementing cloud-based applications into the rest of the turn of the 21st century, the term "cloud computing" the business remains unchanged. The need for business had started to appear, although most of the focus at this integration solutions may actually be more important [1] time was on Software as a service (SaaS). now than ever. In 1999, Salesforce.com was established by Marc Benioff, Through A2A integration processes, companies can Parker Harris, and his fellows. They applied many ensure that cloud-based apps are effectively deployed technologies of consumer web sites like Google and alongside on-premise, legacy systems, as well as other Yahoo! to business applications. They also provided the hosted services. Doing so will avoid the dreaded silo, concept of "On demand" and "SaaS" with their real where an application is left out on its own, unable to business and successful customers. The key for SaaS is communicate or transfer data. being customizable by customer alone or with a small amount of help. Flexibility and speed for application II. Identify areas to migrate: development have been drastically welcomed and accepted by business users. Everything should not be migrated to the cloud. There are some softwares that are best when left on their IBM extended these concepts in 2001, as detailed in the resident places. That's true, at least, for the time being. Autonomic Computing Manifesto -- which described So any move to the cloud will begin by identifying advanced automation techniques such as self-monitoring, which areas of the organization can be migrated. self-healing, self-configuring, and self-optimizing in the According to recent research conducted by Techaisle, management of complex IT systems with heterogeneous many companies have chosen to migrate email, data storage, servers, applications, networks, security storage and industry-specific applications to a cloud- mechanisms, and other system elements that can be based model. virtualized across an enterprise. P a g e | 2 III. Focus on data security: showing the integration of enterprise security management with the cloud. The security of one’s information has become an important issue. Keeping security issues in mind, the cloud providing companies have started integrating the security management at an enterprise level. Figure 2 [4] Figure 2: Integration of cloud with security 5. ARCHITECTURE Mainly, three types of services you can get from a cloud service provider as shown in figure 3. I. Infrastructure as a service- service provider bears all the cost of servers, networking equipment, storage, and back-ups. You just have to pay to take the computing service. And the users build their own application softwares. Amazon EC2 is a great example of this type of service. II. Platform as a service-service provider only provides platform or a stack of solutions for your users.