Home/Kubernetes/Introduction

Introduction to Kubernetes

Kubernetes (often abbreviated as K8s — "K", 8 letters, "s") is an open-source platform for automating the deployment, scaling, and management of containerized applications. This tutorial takes you from zero to comfortably running real workloads on a cluster.

Why does Kubernetes exist?

Containers (Docker, containerd, etc.) solved the packaging problem: your app and its dependencies travel together as one image that runs the same everywhere. But once you move past a single machine, new questions appear:

Where should each container run when you have dozens of servers?
What happens when a container crashes, or an entire server dies at 3 AM?
How do you roll out a new version without downtime — and roll back when it misbehaves?
How do containers find and talk to each other as they move between machines?
How do you add capacity when traffic spikes and remove it when it drops?

Kubernetes answers all of these. It is a container orchestrator: you describe the state you want ("run 3 replicas of this image, expose them on port 80"), and Kubernetes continuously works to make reality match that description.

Key idea — declarative desired state: you never tell Kubernetes how to do something step by step. You declare what you want in YAML manifests, and controllers reconcile the actual state toward it. If a pod dies, Kubernetes notices the drift and replaces it automatically.

What Kubernetes gives you

Capability	What it means
Self-healing	Restarts failed containers, replaces pods on dead nodes, kills containers that fail health checks.
Horizontal scaling	Scale an app up or down with one command, or automatically based on CPU/memory/custom metrics.
Service discovery & load balancing	Gives pods stable DNS names and IPs, and spreads traffic across replicas.
Automated rollouts & rollbacks	Deploys new versions gradually and can revert instantly if something breaks.
Config & secret management	Injects configuration and credentials without rebuilding images.
Storage orchestration	Mounts local disks, cloud volumes, or network storage into containers on demand.
Bin packing	Schedules containers onto nodes efficiently based on their resource requests.

Kubernetes vs. Docker

A common point of confusion: Docker and Kubernetes are not competitors — they operate at different layers.

Docker builds container images and runs individual containers on one machine.
Kubernetes coordinates many containers across many machines. It uses a container runtime (containerd, CRI-O) under the hood to actually run them.

Think of Docker as the shipping container and Kubernetes as the port authority deciding which ship carries which containers, replacing lost ones, and routing cargo.

The vocabulary you'll meet in this tutorial

Object	One-line definition
Cluster	A set of machines (nodes) managed by Kubernetes as one unit.
Node	A single worker machine (VM or physical server) that runs your containers.
Pod	The smallest deployable unit — one or more tightly coupled containers sharing network and storage.
Deployment	Manages a set of identical pod replicas and handles rolling updates.
Service	A stable network endpoint that load-balances across a set of pods.
Ingress	HTTP(S) routing from outside the cluster to services inside it.
ConfigMap / Secret	Configuration data and credentials injected into pods.
Namespace	A virtual sub-cluster used to group and isolate resources.

Try it yourself: a local cluster in minutes

You don't need a cloud account to learn Kubernetes. Any of these run a full cluster on your laptop:

minikube — the classic single-node learning cluster (minikube start).
kind — "Kubernetes in Docker", great for fast, disposable clusters (kind create cluster).
k3s / k3d — a lightweight distribution popular for edge and dev machines.
Docker Desktop — has a built-in one-click Kubernetes cluster (Settings → Kubernetes).

You will also need kubectl, the command-line client used throughout this tutorial. Verify everything works:

# Check the client is installed
kubectl version --client

# List the clusters kubectl knows about
kubectl config get-contexts

# Confirm the cluster is reachable
kubectl cluster-info
kubectl get nodes

NAME       STATUS   ROLES           AGE   VERSION
minikube   Ready    control-plane   2m    v1.30.0

Note: every concept page in this tutorial includes runnable YAML and kubectl commands. Keep a local cluster open in a terminal and try them as you read — it is by far the fastest way to learn.

How this tutorial is organized

Getting Started — this page, plus the cluster architecture that everything else builds on.
Core Workloads — Pods, Deployments & ReplicaSets, and scaling them manually and automatically.
Networking — Services for in-cluster traffic and Ingress for HTTP traffic from outside.
Config & Storage — ConfigMaps, Secrets, Volumes, PersistentVolumes, and StorageClasses.
Operations — Namespaces, RBAC security, and a kubectl cheat sheet you'll come back to daily.

Use the sidebar to jump to any concept, or the Next button below to follow the recommended path.