How Do Kubernetes and Docker Work Together? A Clear Comparison

This article introduces the relationship between Kubernetes (k8s) and Docker, offering a thorough visual explanation for readers interested in understanding both technologies.

Recently a project started using Kubernetes (referred to as k8s). Although I have used it briefly before, I found many concepts and commands unfamiliar, so I wrote this article to give a more comprehensive understanding of k8s concepts and common operations in practice.

There are few articles that compare the background and demand of Kubernetes and Docker. This piece starts from the official definitions and explains their origins and how they differ from traditional technologies.

Brief Introduction

Official Definition 1

: Docker is an open‑source application container engine that lets developers package their applications and dependencies into a portable container, which can be deployed on popular Linux machines and also provides virtualization. Official Definition 2: Kubernetes is an open‑source container‑cluster management system that enables automated deployment, scaling, and maintenance of container clusters.

Comparison with Traditional Technologies

Below are two classic diagrams.

1. From the Virtualization Perspective

The diagram shows the difference between Docker containers (which can be managed by k8s) and traditional virtualization. Traditional virtualization creates multiple virtual machines, each with its own OS, on top of physical hardware. Docker containers run application processes directly on the host kernel without a separate OS, making them lighter than VMs. A Kubernetes cluster consists of many nodes, each running multiple containers, and Kubernetes manages these container environments.

2. From the Deployment Perspective

The second diagram illustrates real‑application deployment. In traditional deployment, all applications run on a single physical node, sharing the same dependencies and lacking isolation. Isolation can be achieved by creating virtual machines, but this is heavyweight. Docker provides a lighter solution by deploying applications in containers managed by a container engine. To orchestrate many containers, Kubernetes (or similar systems) is used, allowing Docker to be managed as a lower‑level component while also supporting other container runtimes like Rocket.

In summary, Kubernetes manages Docker clusters, and while Docker is the most common container runtime, Kubernetes can work with alternatives as well. This simple description should help you understand the relationship between the two.

For more related content, search the previous articles on the Open Source Linux platform.