What Is Cloud Computing? A Beginner’s Guide to Key Concepts and Tools

What Is Cloud Computing

Before introducing the many technical terms, a simple definition of cloud computing is given.

Initially computers were standalone PCs. With the advent of networks, computers could exchange information. As hardware improved, servers appeared and were grouped in data centers. When many computing resources and applications are centralized and accessed over the network, this model is called cloud computing.

Cloud computing essentially aggregates hardware resources (CPU, storage, network) and makes them available over the internet, but its implementation involves multiple layers.

The three service models are:

IaaS – Infrastructure as a Service (raw hardware resources)

PaaS – Platform as a Service (operating system, middleware, runtime)

SaaS – Software as a Service (complete applications)

What Is Virtualization

Virtualization is the foundation of cloud computing. It allows a single physical server to run multiple virtual machines (VMs), each appearing as an independent server while sharing the underlying hardware.

The software that creates and manages these VMs is called a Hypervisor. Hypervisors come in two types: those that run directly on the hardware (bare‑metal) and those that run on top of an existing operating system.

Common hypervisors include VMware, Xen, and KVM. KVM (kernel‑based virtual machine) is a popular open‑source solution on Linux.

To manage virtual machines at scale, cloud platforms such as OpenStack provide a management layer that orchestrates resources from the hypervisor.

Container vs Virtual Machine

Containers offer a lightweight form of virtualization at the process level, providing isolated environments without the overhead of a full guest operating system.

Docker is the most widely used container engine, enabling rapid creation and deployment of containers.

For orchestrating many containers, Kubernetes (K8S) acts as a container management system, handling scheduling, scaling, and health monitoring.

Docker and Kubernetes together represent the PaaS layer, focusing on application deployment rather than raw infrastructure.

Understanding these key terms—VM, KVM, OpenStack, Docker, and Kubernetes—and how they fit into the IaaS, PaaS, and SaaS stack is the first step to mastering cloud computing.