Cloud Computing Kris Jamsa Pdf Free Download

[Yufei Labbe]

Todaythe term cloud computing describes the abstraction of web-based computers, resources, and services that system developers can utilize to implement complex web-based systems. Often these cloud-based resources are viewed as virtual, meaning that if a system or solution needs more resources, such as processors or disk space, the resources can simply be added on demand and usually transparently to the application that uses them. Through their virtual nature, cloud-based solutions can be scaled up or down in size, and the

companies whose solutions reside in the clouds normally pay only for the resources they consume. Thus, companies that once relied on expensive data centers to house their processing resources can now shift their costs and maintenance efforts to pay-as-you-go, scalable, cloud-based alternatives.

For years, when companies wanted to place content on the web, they hired web developers, who created the underlying HTML documents. Through this process, the number of documents on the web exploded to billions worldwide. Web 2.0 is a term used to describe the set of tools and websites that allow users to publish content to the web without the direct use of HTML. Behind the scenes, the tools and sites build the HTML documents for the user and then upload the documents to a web server. TABLE 1-1 describes the common Web 2.0 applications.

Cloud-based applications provide a wide range of solutions to a very large number of users. To help us analyze and describe cloud-based systems, many people refer to a cloud solution in terms of its deployment model and services model. These two terms originated within a cloud computing document from the National Institute of Standards and Technology (NIST), as shown in FIGURE 1-4.

When web developers create web pages, they need to host the corresponding HTML files on a web server before other users can access the content from across the web. Developers have two choices when it comes to publishing their content. First, they can host the pages on their own web server, which may require hardware support and maintenance. Second, the developers can host the files at a server that resides at an Internet service provider (ISP), which allows the developer to focus on web page development as opposed to server management. Today developers can host their web pages at an ISP for a few dollars per month.

A cloud deployment model specifies how resources within the cloud are shared. As discussed in TABLE 1-2, there are four primary cloud deployment models: private cloud, public cloud, community cloud, and hybrid cloud. Each model influences the corresponding scalability, reliability, security, and cost.

A cloud can interact with a client (user or application) in a variety of ways, through capabilities called services. Across the web, three major types, or models, of services have emerged, which are defined in TABLE 1-3.

The software as a service (SaaS) model provides a cloud-based foundation for software on demand. In general, an SaaS solution is web-delivered content that users access via a web browser. The software can reside within any of the deployment-model clouds. FIGURE 1-5 illustrates the SaaS model.

The advantages of SaaS solutions are simplicity of integration (users need only a browser), cost (the data center resides within the cloud), and scalability (customers can add user licenses or seats as needed). The disadvantage of SaaS solutions is the perception of security issues. Users who are new to the cloud may not feel comfortable storing company data in a remote data-storage facility (the cloud).

The platform as a service (PaaS) model provides the underlying hardware technology, such as one or more servers (or virtual servers), operating systems, database solutions, developer tools, and network support, for developers to deploy their own solutions. The hardware and software within a PaaS solution is managed by the platform provider. Developers need not worry about performing hardware or operating system upgrades. Instead, developers can focus on their own applications. FIGURE 1-6 illustrates the PaaS model. Well-known PaaS solution providers include Windows Azure and Google App Engine.

The infrastructure as a service (Iaas) model provides a virtual data center within the cloud. IaaS provides servers (physical and virtualized), cloud-based data storage, and more. Within an IaaS solution, developers must install their

As Amazon evolved its sales plan, the company recognized the value of extending its product base (the things they sell) to other sites. The other sites (Amazon affiliates), in turn, could offer links to products, the sales and fulfillment of which would be handled by Amazon, in a revenue-sharing model. This affiliate program was one of the first cloud-based sales partnerships.

As Amazon continued to grow, its internal developers created a system architecture that was redundant, scalable, and robust. With these services fully operational, Amazon recognized that most software companies would need similar capabilities. To meet that demand, Amazon released Amazon Web Services (AWS), which companies can use to host their own systems. Today, AWS process hundreds of thousands of web-based requests for companies every second!

To complement the processing power of Amazon EC2, Amazon Simple Storage Service (Amazon S3) provides cloud-based data-storage facilities, and companies pay only for the data storage they consume. Behind the scenes, Amazon provides data redundancy.

Exercise Assume your company wants to use Amazon as its disk-backup provider. What pros and cons would you consider? Discuss how you might leverage Amazon Web Services to bring an e-commerce site online.

The cloud is now host to a wide range of large-scale and small-scale (custom) applications. The number and type of applications that users can deploy to the cloud is virtually limitless. Many software companies are now moving key applications from expensive internal data centers to cost-effective and resource-redundant cloud solutions.

As a user, you might already use cloud-based personal productivity software, such as TurboTax, bank-specific bill-pay software, or a stock tool such as E*TRADE. Or you may leverage a cloud-based collaboration tool, such as Google Calendar or Google Docs, to share information and documents with other users. Or you may store files, such as your music, photos, or videos, on cloud-based data storage.

In a similar way, Salesforce.com has recognized that after the sale, customer service is key. As a result, the company released a customer service cloud, which integrates common customer service operations. The software manages the process of responding to customer calls, e-mails, Facebook updates, live chats, and more. After customer cases are resolved, managers can monitor the results via cloud-based dashboards.

When they launch a new website, many developers have visions of having created the next Google, Amazon, or Facebook. Unfortunately, the developers have no way of knowing what the actual user demand will be. Should the site become widely used, it may require additional servers or disk-storage capacity.

Applications that run within the cloud are normally highly scalable. An application administrator can manually add or remove resources, or the application can be configured to scale automatically. As shown in FIGURE 1-8, applications scale through the use of additional servers (physical or virtual) or through the addition of disk-storage space.

Chapter 8, Virtualization, examines desktop and server virtualization in detail. For now think of virtualization as the use of hardware and/or software to create the perception of something. For example, most servers have a CPU that is capable of running a specific operating system, such as Windows or Linux. Using special software, the server can be made to appear as if it has multiple CPUs running the same or different operating systems, as shown in FIGURE 1-9.

In a similar way, most desktop PCs typically run one operating system. Again, using special virtualization software, a desktop PC, as shown in FIGURE 1-10, can be made to appear as if the system is simultaneously running different operating systems. Desktop virtualization provides an excellent solution for developers, application testers, and help desk support personnel who must support multiple operating systems. Rather than having multiple desktop systems on their desk, with each system running a specific operating system, the user can instead use a single desktop PC with multiple (virtual) operating systems.

To start, Gmail, an early cloud-based solution, has become one of the most widely used e-mail services. By storing user e-mails within the cloud, Gmail provides ease of access to e-mail from any computer or handheld device, at any time and from any place.

Google Docs, an online set of collaborative document editing tools, provides many of the common capabilities of Microsoft Office tools, such as Word, Excel, and PowerPoint, from within a web browser, with no software to install and no cost! Not only do the Google Docs tools make it easy for developers to share documents, they provide a preview of how future cloud-based solutions will allow users to perform their daily computing tasks without the need for a computer operating system such as Windows or Mac OS.

As you might expect, Google is not conceding sole custody of the music market to Apple. Google is protective of its web domain and now offers services users can access for common cloud-based solutions.

Through cloud computing, users leverage virtual processing power and data storage via Internet-based computing resources that reside in the cloud. Through CPU (or server) farms and load balancing, cloud-based applications can scale on the fly to meet user demands.

By utilizing the fact that most computers are connected to a network, the grid-computing architects look to design applications that could hand off work across the network to idle CPUs. When the CPU completes its task, it simply returns its result. Shown in FIGURE 1-11, a grid-computing application is well suited for scientific and complex mathematical processing.

3a8082e126