The term virtualization is often considered ambiguous due to its broad range of applications. By analyzing the root word “virtual,” it can be understood as referring to the abstraction from the physical tangibleness.

We definitely have to agree with Allen B. Downey that “ … an  important kind of abstraction is virtualization, which is the process of creating a desirable illusion“. Now, we know we are working within the context of information technology, it is essential to define this “desirable illusion” specifically in relation to these environments. So we can say that …

Virtualization is the process of creating virtual versions of physical resources (on physical resources … emphasis mine), such as servers, storage devices, networks, or operating systems, by using software to abstract and allocate these resources, enabling multiple virtual environments to run simultaneously on a single physical system.

For example, a single piece of hardware — whether it’s a physical server, a storage system, or a network device such as a router or switch — can be abstracted and have its resources sliced into a software-defined instances. This process doesn’t mean the hardware itself becomes virtual; rather, virtualization layers on top of the hardware to extend its functionality. Through this, services such as Virtual Local Area Networks (VLANs), routing, or storage can be logically provisioned and centrally managed, while the underlying hardware continues to provide the essential physical resources. Virtualization doesn’t replace hardware. It needs the real physical device, while the virtual version runs above it — both can exist at the same time.

In IT, infrastructure is usually grouped into three main categories: Computing (servers, processors), Networking (routers, switches, firewalls) and Storage (hard drives, SANs, databases). With today’s technologies and protocols, all three can be virtualized. Deploying virtualization is no longer optional — it is the very foundation of how enterprises operate. Instead of being tied to one physical server, one dedicated network device, or one storage unit, enterprises now create virtual machines, virtual networks, and virtual storage pools that can be provisioned, scaled, and managed far more flexibly.

This principle of virtualization is also what makes cloud computing possible. Providers like AWS, Azure, or Google Cloud operate massive data centers filled with servers, storage arrays, and networking equipment. Instead of assigning entire machines to individual customers, they use virtualization to carve out slices of computing, networking, and storage resources. Each customer experiences an isolated environment that appears to be dedicated hardware, even though it is running on shared physical infrastructure.

Network virtualization also enables Internet Service Providers (ISPs) to use the same physical infrastructure to deliver different classes of service to a wide range of customers and enterprises. Using technologies such as Multiprotocol Label Switching (MPLS), Virtual Routing and Forwarding (VRF), Virtual Extensible Local Area Network (VXLAN), and Virtual Local Area Network (VLAN), ISPs can separate traffic streams, enforce policies, and maintain security and performance across shared infrastructure.

The growth of virtualization has also paved the way for containerization technologies such as Docker and Kubernetes. Containers take the idea of virtualization further by allowing applications and their dependencies to run in lightweight, isolated environments without the overhead of full virtual machines. This shift is central to modern DevOps practices, where CI/CD (Continuous Integration/Continuous Deployment) pipelines automate the process of building, testing, and delivering applications quickly and reliably. In networking, tools like Containerlab extend this concept, allowing engineers to build complex virtual lab environments for testing and training without the need for racks of physical hardware.

Hence, we can see that virtualization is more than just a technical concept — it is the fundamental abstraction that makes modern computing, networking, and storage both flexible and scalable. By creating virtual versions of physical resources, organizations can maximize the use of their infrastructure, reduce costs, and adapt quickly to changing demands. This capability underpins the way enterprises operate today, enabling everything from virtual machines in a data center to entire cloud platforms serving millions of users.

In essence, virtualization — from virtual machines to containers — is the engine of modern IT. It powers the cloud, drives enterprise agility, and sustains the connectivity of smart cities and global digital services. Modern research and innovation continue to push this principle further: doing more with less physical hardware while maintaining performance, scalability, and security. As organizations evolve, virtualization and containerization will remain at the heart of digital transformation, shaping the future of how we build, deploy, and consume technology.