k3d vs K3s

k3d is a free, community-driven wrapper that runs k3s, Rancher Lab’s minimal Kubernetes distribution, inside Docker. It creates single-node and multi-node clusters for local Kubernetes development and can support hot-reloading, Tilt build-deploy-test workflows, and Drone CI service use. Docker is required, while kubectl is used to interact with clusters. For k3d v5.x.x, the overview specifies Docker v20.10.5 or later and runc v1.0.0-rc93 or later. A registries.yaml file configures registries, authentication, and certificates, and documentation covers local registries managed by k3d. Services can be exposed through Ingress or NodePort by mapping container ports to the host. Covered k3s integrations include CoreDNS, local-path-provisioner, Traefik, and the Klipper service load balancer. Installation options include release binaries, Homebrew, AUR, Chocolatey, Scoop, arkade, asdf, and Go. k3d runs on Linux, macOS, Windows, and self-hosted setups. It is not an official Rancher (SUSE) product.

K3s is a certified, lightweight Kubernetes distribution for IoT and edge computing. It runs self-hosted on Linux and is released for x86_64, ARMv7, and ARM64. The distribution arrives as one binary or a minimal container image; the site describes the binary as under 70 MB, while documentation says under 100 MB. Documented uses include edge systems, homelabs, IoT, continuous integration, development, ARM single-board computers, air-gapped environments, and embedded Kubernetes. SQLite is the default datastore, with etcd, MySQL, and Postgres available. K3s packages containerd or cri-dockerd, Flannel, CoreDNS, Traefik, ServiceLB, Kube-router, local-path-provisioner, and Spegel. High-availability deployments can use embedded storage or external MySQL, PostgreSQL, or etcd. Air-gapped installation supports private registries, manually deployed images, or an embedded registry mirror. Security guidance includes hardening and CIS self-assessment material. Automated Kubernetes-native upgrades use Rancher’s system-upgrade-controller.