MODULE 4/LESSON 3
☸️ Docker & Kubernetes

K3s Lightweight Kubernetes

Lightweight Kubernetes for IoT, Edge, and CI/CD pipelines

10 min📊 Diagram
Standard Kubernetes is heavy — the control plane requires gigabytes of RAM and complex etcd cluster management. K3s strips away legacy alpha features, replaces etcd with SQLite, and packages everything into a single 70MB binary. It is fully certified Kubernetes, just smaller and faster.

Key Concepts

Single Binary

No separate containers or processes for API server, scheduler, kubelet, etc. Everything is compiled into one single `k3s` Go binary. Extremely easy to install (curl | sh).

Low Memory Footprint

Standard K8s requires ~1.5GB RAM just to idle. K3s idles at around 512MB RAM. This allows Kubernetes to run on Raspberry Pis, IoT edge devices, and resource-constrained environments.

SQLite by Default

etcd is a complex, memory-hungry distributed key-value store requiring 3+ nodes for quorum. K3s replaces it with SQLite for single-node clusters, or uses external DBs (Postgres/MySQL) for high availability.

Batteries Included

Comes with embedded `containerd` (no need to install Docker), `Flannel` for networking, `CoreDNS`, and `Traefik` Ingress controller pre-installed. It works out of the box.

Standard K8s vs K3s Architecture

Standard K8s (Heavy) API Server Scheduler Cont. Manager etcd (Cluster) kubelet kube-proxy Containerd / Docker Total Memory: ~1.5 GB K3s (Lightweight) k3s server (Single Binary) - API Server - Scheduler / Controller - Kubelet / Kube-proxy SQLite (Replaces etcd) Containerd (Embedded) Total Memory: ~512 MB Stripped
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Senior Architect Insight: If you need a local Kubernetes cluster for development, or a fast ephemeral cluster for CI/CD integration testing, K3s (or K3d, which runs K3s in Docker) is the absolute best choice. It spins up in less than 30 seconds.