#!/bin/sh
set -o errexit
1. Create registry container unless it already exists
reg_name=’kind-registry’
reg_port=’5001’
if [ “$(docker inspect -f ‘{{.State.Running}}’ “${reg_name}” 2>/dev/null || true)” != ‘true’ ]; then
  docker run \
    -d —restart=always -p “127.0.0.1:${reg_port}:5000” —network bridge —name “${reg_name}” \
    registry:2
fi
2. Create kind cluster with containerd registry config dir enabled
TODO: kind will eventually enable this by default and this patch will
be unnecessary.
#
See:
https://github.com/kubernetes-sigs/kind/issues/2875
https://github.com/containerd/containerd/blob/main/docs/cri/config.md#registry-configuration
See: https://github.com/containerd/containerd/blob/main/docs/hosts.md
cat <<EOF | kind create cluster —config=-
kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
containerdConfigPatches:
|-
[plugins.”io.containerd.grpc.v1.cri”.registry]
  config_path = “/etc/containerd/certs.d”
EOF
3. Add the registry config to the nodes
#
This is necessary because localhost resolves to loopback addresses that are
network-namespace local.
In other words: localhost in the container is not localhost on the host.
#
We want a consistent name that works from both ends, so we tell containerd to
alias localhost:${reg_port} to the registry container when pulling images
REGISTRY_DIR=”/etc/containerd/certs.d/localhost:${reg_port}”
for node in $(kind get nodes); do
  docker exec “${node}” mkdir -p “${REGISTRY_DIR}”
  cat <<EOF | docker exec -i “${node}” cp /dev/stdin “${REGISTRY_DIR}/hosts.toml”
[host.”http://${reg_name}:5000“]
EOF
done
4. Connect the registry to the cluster network if not already connected
This allows kind to bootstrap the network but ensures they’re on the same network
if [ “$(docker inspect -f=’{{json .NetworkSettings.Networks.kind}}’ “${reg_name}”)” = ‘null’ ]; then
  docker network connect “kind” “${reg_name}”
fi
5. Document the local registry
https://github.com/kubernetes/enhancements/tree/master/keps/sig-cluster-lifecycle/generic/1755-communicating-a-local-registry
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: ConfigMap
metadata:
  name: local-registry-hosting
  namespace: kube-public
data:
  localRegistryHosting.v1: |
    host: “localhost:${reg_port}”
    help: “https://kind.sigs.k8s.io/docs/user/local-registry/“
EOF

Using The Registry

The registry can be used like this.

1. First we’ll pull an image docker pull gcr.io/google-samples/hello-app:1.0
2. Then we’ll tag the image to use the local registry docker tag gcr.io/google-samples/hello-app:1.0 localhost:5001/hello-app:1.0
3. Then we’ll push it to the registry docker push localhost:5001/hello-app:1.0
4. And now we can use the image kubectl create deployment hello-server --image=localhost:5001/hello-app:1.0

If you build your own image and tag it like localhost:5001/image:foo and then use it in kubernetes as localhost:5001/image:foo. And use it from inside of your cluster application as kind-registry:5000.