Kind Concepts

Internal

• Kind

Overview

kind is a tool for running local Kubernetes clusters using Docker container as cluster nodes. As such, it needs a Docker installation to run and it is similar to Docker Desktop in that respect. kind was primarily designed for testing Kubernetes itself, but may be used for local development or CI.

Cluster

A Kubernetes cluster can be created with kind create cluster. The "nodes" are implemented as Docker containers. Upon creation of a default cluster, it will report two nodes, "kind-control-plane" and "kind-worker". The corresponding Docker containers are:

CONTAINER ID   IMAGE              [...]         NAMES
3108457ff1b6   [...]/kind:v1.27.3-3966ac76      kind-worker
c90cb24cc040   [...]/kind:v1.27.3-3966ac76      kind-control-plane
2702defb0752   [...]/registry:2                 kind-registry

Other cluster container providers can be used, and in that case, the nodes/containers will be reported differently.

Cluster Container Provider

While initializing the cluster, the initialization process will report what container provider it is using.

Registry

Registry Container Provider

While initializing the cluster, the registry can use a different container provider, though usually there should be no good reason do so.

Image Handling

TODO

• https://yunikorn.apache.org/docs/next/developer_guide/env_setup/#loading-your-images
• https://iximiuz.com/en/posts/kubernetes-kind-load-docker-image/

Node

"Node" Image

https://kind.sigs.k8s.io/docs/design/node-image

The “node” image is a Docker image for running nested containers, systemd, and Kubernetes components.

Node Provider

containerd on Node

crictl images

Also see:

crictl