Cloud Computing Basics – 1

Cloud computing is a computing term or metaphor that evolved in the late 2000s, based on utility and consumption of computer resources. Cloud computing is about moving computing from the single desktop PC/Data centers to Internet.

Figure 1.1: Cloud computing terms

Cloud: The “Cloud” is the default symbol of the internet in diagrams

Computing: The broader term of “Computing” encompasses- computation, coordination logic and storage.

Chapter 1.1: Fundamentals of cloud computing

Let’s take an example, you wish to play Ninja Fighters game with your friend on your smartphone. You go to the app store, download the app, log in, find your friend and within five minutes, you’re having fun. This ability to request services for yourself when you need them in cloud computing terms is known as on-demand self-service. You didn’t need to go to a physical store, you didn’t need to call someone to place an order and you didn’t need to sit on hold or wait for anyone else to do anything for you. Another example is of Gmail. You don’t need to install any software nor do you need hard disk space to save your emails -It’s all in the “cloud” managed by Google. In cloud computing, you don’t care what kind of software it is, all you care about is that the service offered is available and reliable. As more users join the game, the cloud is able to quickly grow or shrink to meet the change in demand—elasticity in techie terms. This is possible because a cloud provider, like IBM, has a massive number of servers pooled together that can be balanced between its various customers. But ultimately, you don’t care as long as it’s available for you.

1.1.1Features of Cloud Computing

Figure 2: NIST Visual Model of Cloud Computing Definition

Figure 2: NIST Visual Model of Cloud Computing Definition

The generally accepted definition of Cloud Computing comes from the National Institute of Standards and Technology (NIST). The NIST definition runs to several hundred words but essentially says that:

Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable 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.

What this simply means is the ability for end users to utilize parts of bulk resources and that these resources can be acquired quickly and easily. NIST also offers up several characteristics that it sees as essential for a service to be considered “Cloud”. These characteristics include;

  • On-demand self-service: The ability for an end user to sign up and receive services without the long delays that have characterized traditional IT
  • Broad network access: Ability to access the service via standard platforms (desktop, laptop, mobile etc)
  • Resource pooling: Resources are pooled across multiple customers
  • Rapid elasticity: Capability can scale to cope with demand peaks
  • Measured Service: Billing is metered and delivered as a utility service

1.1.2Types of Cloud

With cloud computing technology, large pools of resources can be connected through private or public networks.

Figure 3: Types of Cloud (Deployment Model)

What are the differences between these types of cloud computing, and how can you determine the right cloud path for your organization? Here are some fundamentals of each to help with the decision-making process().


Public clouds are made available to the general public by a service provider who hosts the cloud infrastructure. Generally, public cloud providers like Amazon AWS, Microsoft and Google own and operate the infrastructure and offer access over the Internet. With this model, customers have no visibility or control over where the infrastructure is located. It is important to note that all customers on public clouds share the same infrastructure pool with limited configuration, security protections and availability variances.

Public Cloud customers benefit from economies of scale, because infrastructure costs are spread across all users, allowing each individual client to operate on a low-cost, “pay-as-you-go” model. Another advantage of public cloud infrastructures is that they are typically larger in scale than an in-house enterprise cloud, which provides clients with seamless, on-demand scalability. These clouds offer the greatest level of efficiency in shared resources; however, they are also more vulnerable than private clouds.

A public cloud is the obvious choice when:

  • Your standardized workload for applications is used by lot of people, such as e-mail.
  • You need to test and develop an application code.
  • You need incremental capacity i.e. the ability to add resources for peak times.
  • You’re doing collaboration projects.


Private cloud is cloud infrastructure dedicated to a particular organization. Private clouds allow businesses to host applications in the cloud, while addressing concerns regarding data security and control, which is often lacking in a public cloud environment.  It is not shared with other organizations, whether managed internally or by a third-party, and it can be hosted internally or externally.

There are two variations of private clouds:

On-Premise Private CloudExternally Hosted
This type of cloud is hosted within an organization’s own facility. A businesses IT department would incur the capital and operational costs for the physical resources with this model. On-Premise Private Clouds are best used for applications that require complete control and configurability of the infrastructure and security.Externally hosted private clouds are also exclusively used by one organization, but are hosted by a third party specializing in cloud infrastructure. The service provider facilitates an exclusive cloud environment with full guarantee of privacy. This format is recommended for organizations that prefer not to use a public cloud infrastructure due to the risks associated with the sharing of physical resources.

Undertaking a private cloud project requires a significant level and degree of engagement to virtualize the business environment, and it will require the organization to reevaluate decisions about existing resources. Private clouds are more expensive but also more secure when compared to public clouds. An Info-Tech survey shows that 76% of IT decision-makers will focus exclusively on the private cloud, as these clouds offer the greatest level of security and control.

When to opt for a Private Cloud?

  • You need data sovereignty but want cloud efficiencies
  • You want consistency across services
  • You have more server capacity than your organization can use
  • Your data center must become more efficient
  • You want to provide private cloud services


Hybrid Clouds are a composition of two or more clouds (private, community or public) that remain unique entities but are bound together offering the advantages of multiple deployment models. In a hybrid cloud, you can leverage third party cloud providers in either a full or partial manner; increasing the flexibility of computing. Augmenting a traditional private cloud with the resources of a public cloud can be used to manage any unexpected surges in workload.

Hybrid cloud architecture requires both on-premise resources and off-site server based cloud infrastructure. By spreading things out over a hybrid cloud, you keep each aspect of your business in the most efficient environment possible. The downside is that you have to keep track of multiple cloud security platforms and ensure that all aspects of your business can communicate with each other.

Here are a couple of situations where a hybrid environment is best:

  • Your company wants to use a SaaS application but is concerned about security.
  • Your company offers services that are tailored for different vertical markets. You can use a public cloud to interact with the clients but keep their data secured within a private cloud.
  • You can provide public cloud to your customers while using a private cloud for internal IT.


A community cloud is a is a multi-tenant cloud service model that is shared among several or organizations and that is governed, managed and secured commonly by all the participating organizations or a third party managed service provider. Community clouds are a hybrid form of private clouds built and operated specifically for a targeted group. These communities have similar cloud requirements and their ultimate goal is to work together to achieve their business objectives.

The goal of community clouds is to have participating organizations realize the benefits of a public cloud with the added level of privacy, security, and policy compliance usually associated with a private cloud. Community clouds can be either on-premise or off-premise.

Here are a couple of situations where a community cloud environment is best:

  • Government organizations within a state that need to share resources
  • A private HIPAA compliant cloud for a group of hospitals or clinics
  • Telco community cloud for telco DR to meet specific FCC regulations

Cloud computing is about shared IT infrastructure or the outsourcing of a company’s technology.  It is essential to examine your current IT infrastructure, usage and needs to determine which type of cloud computing can help you best achieve your goals.  Simply, the cloud is not one concrete term, but rather a metaphor for a global network and how to best utilize its advantages depends on your individual cloud focus.

1.1.3Advantages & Disadvantages

Advantagesof Cloud Computing

Cloud computing presents a huge opportunity for businesses.Let’s look at some of them:

Cost Efficient

Cloud computing is probably the most cost efficient method to use, maintain and upgrade. Traditional desktop software costs companies a lot in terms of finance. Adding up the licensing fees for multiple users can prove to be very expensive for the establishment concerned. The cloud, is available at much cheaper rates and can significantly lower the company’s IT expenses. Besides, there are many one-time-payment, pay-as-you-go and other scalable options available, which makes it reasonable.

Almost Unlimited Storage

Storing information in the cloud gives you almost unlimited storage capacity. Hence, you no more need to worry about running out of storage space or increasing your current storage space availability. 

Backup and Recovery

Since all your data is stored in the cloud, backing it up and restoring the same is relatively much easier than storing the same on a physical device. Furthermore, most cloud service providers are usually competent enough to handle recovery of information. Hence, this makes the entire process of backup and recovery much simpler than other traditional methods of data storage.

Automatic Software Integration

In the cloud, software integration is usually something that occurs automatically. This means that you do not need to take additional efforts to customize and integrate your applications as per your preferences. This aspect usually takes care of itself. You can also handpick just those services and software applications that you think will best suit your particular enterprise.  

Easy Access to Information

Once you register yourself in the cloud, you can access the information from anywhere, where there is an Internet connection.

Quick Deployment

Cloud computing gives you the advantage of quick deployment. Once you opt for this method of functioning, your entire system can be fully functional in a matter of a few minutes, dependingupon the exact kind of technology that you need for your business.

Disadvantages of Cloud Computing

Cloud computing also has some challengessuch as:

Technical Issues

Though it is true that information and data on the cloud can be accessed anytime and from anywhere at all, there are times when this system can have some serious dysfunction. Technology is always prone to outages and other technical issues. Even the best cloud service providers run into this kind of trouble, in spite of keeping up high standards of maintenance. Besides, you will need a very good Internet connection to be logged onto the server at all times. You will invariably be stuck in case of network and connectivity problems. 

Security in the Cloud

The other major issue while in the cloud is that of security issues. Before adopting this technology, you should know that you will be surrendering all your company’s sensitive information to a third-party cloud service provider. This could potentially put your company to great risk. Hence, you need to make absolutely sure that you choose the most reliable service provider, who will keep your information totally secure.

Prone to Attack

Storing information in the cloud could make your company vulnerable to external hack attacks and threats. As you are well aware, nothing on the internet is completely secure and hence, there is always the lurking possibility of stealth of sensitive data.