Cloud Computing Simplified: Explore Application of Cloud, Cloud Deployment Models, Service Models and Mobile Cloud Computing (English Edition)

CHAPTER 1

Overview of Cloud Computing

In this chapter, we will explore the meaning of and various concepts related to cloud computing. We will also discuss its history, characteristics, advantages, disadvantages, and cloud service models including a brief description of SaaS, PaaS and IaaS. This chapter also deals with an overview of various cloud computing models. At the end of the chapter, we will have a look at various companies that provide a range of cloud services.

Structure

In this chapter, we will discuss the following topics:

Introduction to cloud computing

What is cloud computing?

History of cloud computing

Characteristics of cloud computing

Advantages of cloud computing

Disadvantages of cloud computing

Cloud service models

Cloud computing deployment models

Cloud computing companies

Conclusion

Questions and exercises

Objectives

After studying this unit, you will be able to:

Understand the meaning of cloud computing

Know from where the concept of cloud computing came from

Gain knowledge of the various characteristics as well as the pros and cons of cloud computing

Discuss various cloud service models and deployment models

Know about companies providing cloud computing services

Introduction to cloud computing

To begin with cloud computing, let’s take the example of a person named Saurish who owns a small business company. He has 20 employees in his company. These people perform different jobs such as accounting, taxation, etc. To do all this work, they need desks, chairs, computers, services for databases, software, backup system, servers, network to keep themselves connected, and of course, they need to be connected to their clients. Apart from this, Saurish needs an IT employee to install this set up, troubleshoot the problems, and maintain the safety and security of data. Now, as the company grows, Saurish needs to indulge in more employees, more space to accommodate people and data, and more data to secure, hence resulting in more risks and threats.

No doubt, this creates burden and stress for Saurish. He has to manage the availability of resources for all the people, provide them the access, and that too on time. He needs a large set up of IT infrastructure which will considerably result in spending a huge amount of money. To get rid of all these problems, the idea of cloud computing arose. With this technique, he can store all these things at a safe and secure place named as cloud. He can simply access all these things with the help of a web browser. All his company’s work, including applications, media, and data can be saved on the internet and he can access all services including hardware, software, databases, networking, and applications over the internet whenever he requires. He doesn’t have to care about the location of the hardware, software, and their working. He can access a shared pool of computing resources from anywhere and at any time. Moreover, he needs to pay only for those resources that he uses. Hence, this reduces a large amount of expenditure to a low amount by reducing the IT infrastructure cost.

Cloud computing is the latest generation technology that is designed to deliver services over the network or internet. In simple words, cloud computing is the process of storing and accessing all types of data including music, files, documents, videos, photos, etc. on the internet instead of your local disk or any other form of storage device. One can access services like applications, tools, and storage space rather than physically having all those services at the user’s end. With this technique, one can store the data and program on the internet instead of the hard disk and can access from anywhere with the help of an internet connection. Every user is provided with a user ID and password to access data through cloud computing. Services offered by a cloud are available on demand and are sometimes free or bought on pay-per-use basis. By the term pay-per-use, we mean that users or organizations have to pay for only those resources that they use. Hence, this it contributes to the idea of low expenditure also. You need not invest a huge amount of money to access cloud services.

What is cloud computing?

Cloud computing refers to the availability of an IT infrastructure and services like development platform, hard disk, computing power, software application, and database over the internet on an on-demand and pay-per-use basis.

The following figure shows a graphical illustration of cloud computing:

Figure 1.1: Cloud computing idea

We can easily connect to a cloud system using a laptop, computer, or mobile. Companies like Google, Oracle, Amazon, Microsoft, etc. provide us with the facility of cloud computing. These companies are solely responsible for the management of the cloud computing. They keep on updating and modifying their services which improves the accessing speed for data, the capacity of servers, and the quality of their services. They have ample amount of storage for data and fast processing of servers because of which, the user can access data quickly from anywhere at a high speed with just the help of an internet connection. The user does not need to bother about the details and can perform his/her job perfectly and sincerely.

Some examples of applications that use cloud computing from our daily life are as follows:

While using e-mail, our data gets stored on the cloud server of the e-mail providers and not on our computer. We can access our e-mails from any computer and other devices connected to the internet.

All pictures and videos that we post on Facebook get stored on the cloud system of Facebook.

Videos that we watch on YouTube are stored on the cloud system. This is the reason that we can watch them anytime and anywhere.

All digital photos stored on sites like Picasa and Flickr are actually stored on the cloud servers of these sites.

Google Docs is also an example of a cloud service. With it, users can upload documents, spreadsheets, and presentations to Google’s data servers and edit them using the Google application.

History of cloud computing

When we talk about cloud computing, it seems that it is a matter of the new generation that came into picture just a few years ago. However, this technique actually roots back to 60 years ago. In the 1950s, all organizations used to work on mainframe computers to process their data. At that time, mainframe computers were huge and expensive too. The idea of linking different computers at various places for scientific and military purposes was also developed at that time.

American scientist John McCarthy created the theory of a time-sharing system where time is allotted to each user of a group to access resources. In the middle of 1960, an American computer scientist named J.C.R. Licklider came up with the idea for an interconnected system of computers. This idea proved to be a boon to the world of technology. In 1961, John McCarthy, who coined the term AI (artificial intelligence), suggested that computing will be sold as a utility like electricity or water one day.

In 1969, Licklider’s revolutionary idea helped Bob Taylor and Larry Roberts develop the concept of ARPANET (Advanced Research Project Agency Network). ARPANET was termed as the predecessor of the internet. It was the first network that could share information among different computers that were physically apart. This concept is the basis of cloud computing as it gives the picture of an interconnected world with the ability to access programs and data.

Following ARPANET, researchers began to assemble the network of networks which developed into the modern internet. In 1990, the computer scientist Tim Berners Lee invented the World Wide Web and the online internet was visible to all. He introduced the concept of hypertext documents. Then, data could be made accessible from any node on the network. With this, millions of machines were connected to the internet. By this time, e-commerce also started gaining popularity. The client-server model of computing was implemented.

Client-server computing is a type of computing in which all data and software applications reside on the server side. If a user wants to access any application or data, he needs to connect to the server, gain access, and perform his task. Then the concept of distributed computing came into picture. It is the process in which all the computers are networked together and resources are shared as per the requirement. Websites act as the front end for users and the servers on the WWW host the backend logic.

In 1997, Professor Ramnath Chellappa from Emory University delivered a lecture and mentioned the term cloud computing in his lecture. He is credited for being the person who coined the term cloud computing. Although at this time, the grid computing technique was very popular as it provides the access of grid-networked resources of organizations across continents, the problem was that non-specialist users or developers still did not have access to resources.

In 1999, the launch of salesforce.com became a major milestone in the history of cloud computing. It was the first company to offer business applications over the internet via the cloud, now known as software-as-a-service (SaaS). After that, in 2002, Amazon launched its Amazon Web Service (AWS). This was a platform designed to deliver cloud computing services including storage and computing power to customers. Then in 2006, Amazon launches their commercial web service named EC2 (Elastic Compute Cloud). It was a web service that allowed small organizations and individuals to rent computers on which they could run their own applications. EC2 became the basis for the emergence of web-scale businesses like Spotify, Uber, and Netflix.

In 2009, Google Apps was launched to deliver cloud services. It was available on both mobiles and the web. In 2010, Microsoft also entered the cloud arena with the launch of its cloud platform, Azure. Following this, IBM launched SmartCloud in 2011 to provide cloud computing business applications. Other companies like HP and Oracle also joined the race to offer their services in cloud computing for fulfilling the need for greater storage.

Characteristics of cloud computing

Cloud computing is the need of the hour. It is becoming more and more popular day by day. Various companies are providing cloud computing services to store data along with unique characteristics. According to NIST, cloud computing is a model for enabling ubiquitous, convenient, and on-demand network access to a shared pool of configurable resources that can be rapidly provisioned and released with minimal management effort or service provider interaction. The major characteristics of cloud computing model are given below.

On-demand self-service

It is one of the important and usable features of cloud computing. The cloud computing services does not require any human administrator. All computing services like storage, applications, networking, etc. can be accessed whenever required and without any interaction with service providers. Users or organizations can use the web self-service portal to access the required resources. Using this interface, they can also access their cloud account and have a look at the list of services and storage allotted to them.

Broad network access

All computing resources offered by cloud servers are available over the network and users can access them from anywhere and at anytime with the help of their devices and internet connection.

Resource pooling

In order to serve multiple customers, service providers create a pool of various physical as well as virtual computing resources. This pool should be large and flexible enough to meet all the requirements of multiple clients. These resources can be assigned and reassigned on the customer’s demand. Customers generally don’t have any knowledge or control over the exact physical location of the resources provided to them. But they have the capability to specify a location at a higher level of abstraction.

Rapid elasticity

It is one of the key features of cloud computing. In cloud computing, computing services can be elastically provisioned or released. This means that cloud computing has the ability to assign resources when they are in need by the customers and remove them when they don’t need them. Hence, whenever a user requires a service, it is provided to him and it is scaled out as soon as its requirement is over.

Computing services should have IT resources that can be scaled out and in quickly and on a need basis, so that they can be automatically provisioned and released. The usage, capacity, and cost can be scaled up or down with no additional contract or penalty.

Measured service

Cloud computing is based on the pay-per-use principle. Users are charged for the resources that they use. Hence, the cost is variable and is based on the consumption of resources. A cloud system leverages a metering capability to measure the resources used. All usage, that is, the amount of data transferred, the amount of storage space used etc. is measured. This measurement is also helpful for service providers in allocating resources to the customers in the best possible way. The resources usage is monitored, controlled, and reported. This maintains transparency for customers and providers.

Multi-tenancy

Cloud computing supports a multi-tenant model. By multi-tenancy, we mean that multiple customers can share the same resource or application while maintaining privacy and security. With this, only one server instance can run among a large number of customers and updates can be deployed to them easily. This is also cost efficient.

Advantages of cloud computing

Cloud computing is very popular among businesses as it provides efficiency, saves time and money, provides a platform for innovation, and has many more benefits. By using a cloud solution for your business, you can protect it from many problems. Let us discuss the benefits that a cloud system can provide to your business.

Economical

One of the biggest benefits of cloud computing is that you don’t need to invest a large sum of money to buy IT infrastructure. Moving to cloud computing provides access to various computing resources at a low cost. You don’t need to buy and maintain expensive infrastructure, hardware, facilities, or invest money to recruit an expert staff and IT team to manage the set up. There are no administrative, operational, and upfront costs. Your business can grow efficiently with the help of cloud computing.

Unlimited storage capacity and universal access

Cloud service providers provide you with ample amount of storage capacity to store your data. You can expand your storage capacity whenever you require. Cloud computing enables you to work and gain access from anywhere, that is, it provides universal access to your data. Uploading data to a cloud system corresponds to accessibility from any computer or device with just an internet connection.

Scaling

Scaling means the ability to increase or decrease the IT resources in your business infrastructure to meet the business demands. It is the major advantage of cloud computing. With this feature, a business can increase or decrease performance, functionalities, and resources as per the requirements. Scaling out and scaling in of IT resources as per the demand is the major reason for the popularity of cloud computing in the market.

Redundancy

Redundancy means to create duplicates. In cloud systems, various copies of our data are maintained by service providers on different machines so as to provide universal access and recovery of data in case any failure occurs at any data center or the data from one machine gets lost. It is a major benefit of cloud computing. The redundancy feature of cloud storage provides you with the facility of automatic data backups and access from any device at any time and any place.

Increased security and reliability

Data theft is a major concern for all organizations. Storing data in a cloud system helps you to secure the data. It provides the measures to protect your data and ensure the safety of the data. It protects your business from internal threats, guards you against internal threats, and prevents data loss.

Ensures backup and recovery of data

Storing data in cloud systems offers the feature of high availability. Because of this feature, you can recover your data as it is always available on many machines. If in any case, data on one machine gets lost or your phone gets damaged, you can easily retrieve the required data. Cloud based services provide quick recovery in any type of failure.

Disadvantages of cloud computing

Every technique has positive and negative impacts. The same goes for cloud computing. Although cloud computing is very popular among enterprises, it still has some issues. Let us discuss them here.

Internet connection

Cloud computing resources can be accessed only with the help of an internet connection. If you do not have an internet connection or the speed is slow, then you will not be able to access the cloud. There is no other way of accessing than to access the applications, software, and resources on the cloud. So, you are basically dependent on the quality of the internet connection to access the tools available on the cloud.

Security issues

Although cloud service providers provide us a great level of security. Sharing our data on cloud systems may be risky sometimes as it may provide a way for hackers to steal the information. The presence of data on the cloud may allow hackers to find loopholes in the framework and can hence be dangerous for the security of our information. Data stored on the cloud system is always a security challenge for service providers and a concern for businesses.

Downtime

Downtime is the worst disadvantage of cloud computing. Downtime means the time during which a machine or computer is out of use or not available. This may happen due to overload of traffic on servers from various clients and service providers may encounter technical problems. This may lead to a temporary downtime in cloud services. This may affect your business. Moreover, cloud systems are internet-based which means that if your internet speed is down, you will not be able to access resources stored on clouds. Similarly, the internet speed of a cloud provider,