Revisiting cloud computing

In this section, we will look at what cloud computing is in simple terms, what benefits it provides, how it influences design thinking, as well software development processes.

Cloud computing is utility-style computing with a business model similar to what is provided by businesses selling utilities such as LPG and electricity to our homes. You don’t need to manage the production, distribution, or operation of electricity. Instead. you focus on consuming it effectively and efficiently by just plugging in your device to the socket on the wall, using the device, and paying for what you consume. Although this example is very simple, it is still very relevant as an analogy. Cloud computing providers provide access to compute, storage, databases, and a plethora of other services, including Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS) over the internet.

Figure 1.1 – Cloud computing options

Figure 1.1 illustrates the cloud computing options most commonly used:

• IaaS provides infrastructure such as networking to connect your application with other systems in your organization, as well as everything else you would like to connect to. IaaS gives you access to computational infrastructure to run your application, equivalent to Virtual Machines (VMs) or bare-metal servers in traditional data centers. It also provides storage for host data for your applications to run and operate. Some of the most popular IaaS providers are Amazon EC2, Azure virtual machines, Google Compute Engine, Alibaba E-HPC (which is very popular in China and the Greater China region), and VMware vCloud Air.
• PaaS is another kind of offering that provides you with the flexibility to focus on building applications rather than worrying about how your application will be deployed, monitored, and so on. PaaS includes all that you get from IaaS but also middleware to deploy your applications, development tools to help you build applications, databases to store data, and so on. PaaS is especially beneficial for companies adopting microservices architecture. When adopting microservices architecture, you also need to build an underlying infrastructure to support microservices. The ecosystem required to support microservices architecture is expensive and complex to build. Making use of PaaS to deploy microservices makes microservices architecture adoption much faster and easier. There are many examples of popular PaaS services from cloud providers. However, we will be using Amazon Elastic Kubernetes Service (EKS) as a PaaS to deploy the sample application we will explore hands-on with Istio.
• SaaS is another kind of offering that provides a complete software solution that you can use as a service. It is easy to get confused between PaaS and SaaS services, so to make things simple, you can think of SaaS as services that you can consume without needing to write or deploy any code. For example, it’s highly likely that you are using an email service as SaaS with the likes of Gmail. Moreover, many organizations use productivity software that is SaaS, and popular examples are services such as Microsoft Office 365. Other examples include CRM systems such as Salesforce and enterprise resource planning (ERP) systems. Salesforce also provides a PaaS offering where Salesforce apps can be built and deployed. Salesforce Essentials for small businesses, Sales Cloud, Marketing Cloud, and Service Cloud are SaaS offerings, whereas Salesforce Platform, which is a low-code service for users to build Salesforce applications, is a PaaS offering. Other popular examples of SaaS are Google Maps, Google Analytics, Zoom, and Twilio.

Cloud services providers also provide different kinds of cloud offerings, with varying business models, access methods, and target audiences. Out of many such offerings, the most common are a public cloud, a private cloud, a hybrid cloud, and a community cloud:

• A public cloud is the one you most probably are familiar with. This offering is available over the internet and is accessible to anyone and everyone with the ability to subscribe, using a credit card or similar payment mechanism.
• A private cloud is a cloud offering that can be accessed over the internet or a restricted private network to a restricted set of users. A private cloud can be an organization providing IaaS or PaaS to its IT users; there are also service providers who provide a private cloud to organizations. The private cloud delivers a high level of security and is widely used by organizations that have highly sensitive data.
• A hybrid cloud refers to an environment where public and private clouds are collectively used. Also, a hybrid cloud is commonly used when more than one cloud offering is in use – for example, an organization using both AWS and Azure with applications deployed and data flowing across the two. A hybrid cloud is a good option when there are data and applications that are required to be hosted in a private cloud due to security reasons. Conversely, there may be other applications that don’t need to reside in the private cloud and can benefit from the scalability and elasticity features of a public cloud. Rather than restricting yourself to a public or private cloud, or one cloud provider or another, you should reap the benefit of the strengths of various cloud providers and create an IT landscape that is secure, resilient, elastic, and cost-effective.
• A community cloud is another cloud offering available to a set of organizations and users. Some good examples are AWS GovCloud in the US, which is a community cloud for the US government. This kind of cloud restricts who can use it – for example, AWS GovCloud can only be used by US government departments and agencies.

Now that you understand the true crux of cloud computing, let’s look at some of its key advantages in the following section.

Advantages of cloud computing

Cloud computing enables organizations to easily access all kinds of technologies without going through high upfront investment in expensive hardware and software procurement. By utilizing cloud computing, organizations achieve agility, as they can innovate faster by having access to high-end compute power and infrastructure (such as a load balancer, compute instances, and so on) and also to software services (such as machine learning, analytics, messaging infrastructure, AI, databases, and so on) that can be integrated as building blocks in a plug-and-play style to build software applications.

For example, if you’re building a software application, then most probably it will need the following:

• Load balancers
• Databases
• Servers to run and compute servers to host an application
• Storage to host the application binaries, logs, and so on
• A messaging system for asynchronous communication

You will need to procure, set up, and configure this infrastructure in an on-premises data center. This activity, though important for launching and operationalizing your applications in production, does not produce any business differentiators between you and your competition. High availability and resiliency of your software application infrastructure is a requirement that is required to sustain and survive in the digital world. To compete and beat your competition, you need to focus on customer experience and constantly delivering benefits to your consumers.

When deploying on-premises, you need to factor in all upfront costs of procuring infrastructure, which include the following:

• Network devices and bandwidth
• Load balancers
• A firewall
• Servers and storage
• Rack space
• Any new software required to run the application

All the preceding costs will incur Capital Expenditures (CapEx) for the project. You will also need to factor in the setup cost, which includes the following:

• Network, compute servers, and cabling
• Virtualization, operating systems, and base configuration
• Setup of middleware such as application servers and web servers (if using containerization, then the setup of container platforms, databases, and messaging)
• Logging, auditing, alarming, and monitoring components

All the preceding will incur CapEx for the project but may fall under the organization’s Operating Expenses (OpEx).

On top of the aforementioned additional costs, the most important factor to consider is the time and human resources required to procure, set up, and make the infrastructure ready for use. This significantly impacts your ability to launch features and services on the market (also called agility and time to market).

When using the cloud, these costs can be procured with a pay-as-you-go model. Where you need compute and storage, it can be procured in the form of IaaS, and where you need middleware, it can be procured in the form of PaaS. You will realize that some of the functionality you need to build might be already available as SaaS. This expedites your software delivery and time to market. On the cost front, some of the costs will still incur CapEx for your project, but your organization can claim it as OpEx, which has certain benefits from a tax point of view. Whereas it previously took months of preparation to set up all that you needed to deploy your application, it can now be done in days or weeks.

Cloud computing also changes the way you design, develop, and operate IT systems. In Chapter 4, we will look at cloud-native architecture and how it differs from traditional architecture.

Cloud computing makes it easier to build and ship software applications with low upfront investments. The following section describes microservices architecture and how it is used to build and deliver highly scalable and resilient applications.