Introduction about cloud computing and its basics

Introduction about cloud computing and its basics

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  Introduction
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  CLOUD COMPUTING ATA GLANCE  Computing is being transformed to a model consisting of services that are commoditized and delivered in a manner similar to utilities such as water, electricity, gas, and telephony. In such a model, users access services based on their requirements regardless of where they are hosted.  This vision of computing utilities based on a service provisioning model anticipated the massive trans formation of the entire computing industry in the 21st century whereby computing services will be readily available on demand, like other utility services such as water, electricity, telephone, and gas available in today’s society.  Cloud computing allows renting infrastructure, runtime environments, and services on pay-per-use basis.
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  Vision of cloudComputing
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  Defining a Cloud
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  Definition • “Cloud computingrefers to both the applications delivered as services over the Internet, and the hardware and system software in the datacenters that provide those services.” • Definition proposed by American National Institute of Standards and Technology (NIST): “Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of confi gurable computing resources (e.g. networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.”
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  Basic Concepts • Anotherimportant aspect of Cloud computing is its utility-oriented approach. More than any other trend in distributed computing, Cloud computing focuses on delivering services with a given pricing model; in most of the cases a “pay-per-use” strategy. It makes possible to access online storage, to rent virtual hardware, or to use development platforms and pay only for their effective usage, with no or minimal upfront costs. We can define three criteria to discriminate whether a service is delivered in the Cloud computing style:  The service is accessible via a Web browser (non-proprietary) or Web services API.  Zero capital expenditure is necessary to get style  You pay only for what you use as you use it.  Even though many Cloud computing services are freely available for single users, enterprise class services are delivered according a specific pricing scheme. In this case, users subscribe to the service and establish with the service provider a Service Level Agreement (SLA) defining quality of service pa rameters under which the service is delivered
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  Buyya Definition ofCloud Computing • “A Cloud is a type of parallel and distributed system consisting of a collection of interconnected and virtualized computers that are dynamically provisioned and presented as one or more unified computing resources based on service-level agreements established through negotiation between the service provider and consumers.”
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  A Closer Look •Cloud computing is helping enterprises, governments, public and private institutions, as well as re search organizations shape more effective and demand-driven computing systems.
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  Market Section ofCloud Computing • Large enterprises can offload some of their activities to Cloud based systems. • Small enterprises and start-ups can afford to translate into business results their ideas more quickly without excessive upfront costs. • System developers can concentrate on the business logic rather than dealing with the complexity of infrastructure management and scalability. • End users can have their documents accessible from everywhere and any device.
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  Cloud Deployment Models •Public Clouds are the most common deployment models in which necessary IT infrastructure (e.g., virtualized Data Center) is established by a 3rd party service provider who makes it available to any consumer on subscription basis. Such Clouds are appealing to users as they allow them to quickly leverage compute, storage, and application services. In this environment, users’ data and applications are deployed on Cloud Data centers on the vendor’s premises. • The use of Cloud-based in-house solutions is also driven by the need of keep ing confi dential information within the organization’s premises. Institutions such as governments and banks with high security, privacy, and regulatory concerns prefer to build and use their own private or enterprise Clouds. • Whenever private Cloud resources are unable to meet users quality-of-service requirements such the deadline, hybrid computing systems, partially composed by public Cloud resources and privately owned infrastructures, are created to serve the organization’s need.
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  Deployment Models
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  Cloud-Computing Reference Model
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  Infrastructure-as-a-Service • Infrastructure-as-a-Service solutionsdeliver infrastructure on demand in the form of virtual hardware, storage, and networking. • Virtual hardware is utilized to provide compute on demand in the form of virtual machines instances. These are created on users’ request on the provider’s infrastructure, and users are given tools and interfaces to confi gure the software stack installed in the virtual machine. • The pricing model is usually defined in terms of dollars per hours, where the hourly cost is infl uenced by the characteristics of the virtual hardware.
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  Platform-as-a-Service • They deliverscalable and elastic run time environments on demand that host the execution of applications. • These services are backed by a core middleware platform that is responsible for creating the abstract environment where applications are deployed and executed. • It is the responsibility of the service provider to provide scalability and to manage fault-tolerance, while users are requested to focus on the logic of the application developed by leveraging the provider’s APIs and libraries.
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  Software-as-a-Service • Software-as-a-Service solutionsprovide applications and services on demand. Most of the common functionalities of desktop applications—such as office automation, document management, photo editing, and customer relationship management (CRM) software—are replicated on the provider’s infrastructure, made more scalable, and accessible through a browser on demand. • These applications are shared across multiple users, whose interaction is isolated from the other users. • The SaaS layer is also the area of social networking Websites, which leverage Cloud-based infrastructures to sustain the load generated by their popularity.
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  Characteristics and Benefits no upfront commitments  on demand access  nice pricing  simplified application acceleration and scalability  efficient resource allocation  energy efficiency  seamless creation and the use of third-party services.
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  Benefits of CloudComputing  The increased economical return due to the reduced maintenance costs and operational costs related to IT software and infrastructure. This is mainly because IT assets, namely software and infrastructure, are turned into utility costs, which are paid for as long as they are used and not upfront. Capital costs are costs associated to assets that need to be paid in advance to start a business activity.  Cloud computing transforms IT infrastructure and software into utilities, thus significantly contributing in increasing the net gain. Moreover, it also provides an opportunity for small organizations and start-ups: these do not need large investments to start their business but they can comfortably grow with it.  Finally,maintenance costs are significantly reduced: by renting the infrastructure and the application services, organizations are not responsible anymore for their maintenance.
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  HISTORICAL DEVELOPMENTS
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  Distributed Systems • “Adistributed system is a collection of independent computers that appears to its users as a single coherent system.” • Distributed systems often exhibit other properties such as heterogeneity, openness, scalability, transparency, concurrency, continuous availability, and independent failures. • Three major milestones have led to Cloud computing: mainframe computing, cluster computing, and Grid computing
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  Virtualization • It encompassesa collection of solutions allowing the abstraction of some of the fundamental elements for computing such as: hardware, runtime environments, storage, and networking. • This is the base technology that enables Cloud computing solutions delivering virtual server on demands, such as Amazon EC2, RightScale, VMware vCloud, and others.
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  Web 2.0 • TheWeb is the primary interface through which Cloud computing deliver its services. • Examples of Web 2.0 applications are Google Documents, Google Maps, Flickr, Facebook, Twitter, YouTube, de.li.cious, Blogger, and Wikipedia.
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  Service-Oriented Computing Service-Oriented Computing(SOC) supports the development of rapid, low-cost, fl exible, interoperable, and evolvable applications and systems . Quality of Service identifies a set of functional and non-functional attributes that can be used to evaluate the behavior of a service from different perspectives. These could be performance metrics such as response time, or security attributes, transactional integrity, reliability, scalability, and availability. QoS requirements are established between the client and the provider between a Service Level Agreement (SLA) that identifies the minimum values (or an acceptable range) for the QoS attributes that need to be satisfi ed upon service call.
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  Utility-Oriented Computing • Utilitycomputing is a vision of computing, defining a service provisioning model for compute services in which resources such as storage, compute power, applications, and infrastructure are packaged and offered on a pay-per-use basis..