Chapter 1: What Is Cloud Computing?
Cloud computing has become the default option to design, build, and implement Information Technology (IT) applications for businesses across the globe. In the old days, you would host the entire infrastructure, hire a group of developers, and design each component and process required to build your applications. This approach not only ate into the bottom line, but also often did not follow best practices. It also lacked flexibility and scope for innovation.
Understanding cloud computing has become vital for IT professionals worldwide if they are to sustain their jobs and make progress in their careers. You can no longer deliver old-school solutions to your clientsâit is simply not cost-effective in today's fast-paced IT world.
In addition, architecting solutions for the cloud comes with its own challenges, such as security considerations and network connectivity. This makes it crucial to upskill so that you can gain a deep understanding of how to build resilient, scalable, and reliable solutions that can be hosted in the cloud.
In this chapter, we introduce you to the concept of cloud computing, what it includes, and the key advantages of moving to the cloud. We also discuss the various cloud computing models, as well as deployment options for the cloud. Understanding the key differences between the models and deployment options and their use cases and benefits is fundamental to formulating an effective cloud-adoption strategy for your business.
We also look at a high-level overview of virtualizationâa principal ingredient that has made cloud computing possible.
This chapter covers the following topics:
- What is cloud computing?
- Exploring the basics of virtualization
- Exploring cloud computing models
- Understanding cloud deployment models
What is cloud computing?
Cloud computing is a term used to describe the on-demand access to IT services that comprise compute, network, storage, and software services from third-party suppliers, usually via the public internet or some form of direct wide-area network (WAN) access. Companies can provision necessary IT applications for their organization without having to procure and manage their own infrastructure to host those applications. Instead, they lease/rent the required IT infrastructure from such third-party providers.
Cloud computing has existed for many years in some form, since the invention of the internet. In the old days, Hotmail (first launched in 1996 and now branded as Microsoft Outlook) was a prime example of early cloud computing. You could set up email accounts for your colleagues and yourself on Hotmail and use them to communicate. An alternative would be to host your own email servers' (the infrastructure) network connectivity, as well as the email application (the email software). This would ultimately mean additional costs as well as management overheads to maintain the email servers you hosted.
Today, cloud computing has become mainstream and is, in several cases, the default option for many companies and start-ups. Currently, Amazon Web Services (AWS) is the largest provider of cloud computing services, offering a variety of cloud IT services in the form of infrastructure, platform, and software solutions. You can opt to consume these services rather than creating your own dedicated environment to host your business applications. The sheer size of AWS enables it to actually provide the necessary components to host your business applications at a fraction of the cost, while providing high availability (HA), security, and resilience.
The six advantages of cloud computing
Let's take a look at the six advantages of cloud computing, according to AWS (AWS, Six Advantages of Cloud Computing, https://docs.aws.amazon.com/whitepapers/latest/aws-overview/six-advantages-of-cloud-computing.html), as depicted in the following screenshot:
Figure 1.1 â The six advantages of cloud computing
Tip
The AWS Certified Cloud Practitioner examination assumes that you have these six advantages memorized when testing the Define the AWS Cloud and its value proposition objective.
Let's look at these advantages in detail, as follows:
- Trade capital expense for variable expense: One of the primary benefits of moving to cloud computing instead of hosting your own on-premises infrastructure is the method of paying for that infrastructure. Traditionally, you would have to procure expensive hardware and invest precious business capital to acquire infrastructure components necessary for building an environment to host applications.
With cloud computing, you pay for the same infrastructure components only as and when you consume them. This on-demand, pay-as-you-go model also means that you save costs when you are not utilizing resources.
The shift away from capital expense (CAPEX) for variable expense, also known as operating expense (OPEX), means that you can direct your precious business capital to more important areas of investment, such as developing new products or improving your marketing strategy.
- Benefit from massive economies of scale: As an individual business, you would generally have to pay retail rates to purchase necessary IT hardware and build an environment that can be used to host your applications. Cloud providers such as AWS, however, host infrastructure for hundreds of thousands of customers, and even get involved in innovating and having components manufactured to their specifications. This gives even greater economies of scale and allows them to offer lower pay-as-you-go rates to customers.
- Stop guessing capacity: Traditionally, while carrying out capacity planning, you would procure necessary hardware components for future growth. Predicting future growth is extremely difficult, and this often meant that you would overprovision your environment. The result would be expensive idle resources simply going to waste. The fact that you would have made large CAPEX to acquire those components would ultimately be detrimental to the balance sheet due to the rapid loss in value arising from depreciation. On the flip side, some companies may end up underprovisioning capacity to save on costs. This can have an adverse effect on corporate image, ifâfor exampleâdue to underprovisioned resources your customers are not able to complete transactions or suffer from poor performance.
With cloud computing and sophisticated management software, you can provision the necessary infrastructure when you need it most. Moreover, with monitoring and automation tools offered by cloud vendors such as AWS, you can automatically scale out your infrastructure as demand increases and scale back in when demand falls. Doing so will allow you to pay only for what you consume, when you consume it.
- Increase speed and agility: Cloud vendors such as AWS enable you to launch and configure new IT resources in a few mouse clicksâfor example, you can provision a new fleet of servers for your developers within minutes, allowing your organization to exponentially increase its agility in building infrastructure and launching applications. If you are building test and development environments or performing experimental work as part of researching a new product/service, then once those tasks are complete you can just as quickly terminate those environments. Equally, if a particular project is being abandoned midway, you do not need to be worried about having any physical wastageâyou just turn off or terminate what you no longer need. By contrast, prior to the invention of virtualization technologies (discussed later), prov...
