Private Registries

Some users may want to test applications on kind that require pulling images from authenticated private registries, there are multiple ways to do this.

Use ImagePullSecrets

Kubernetes supports configuring pods to use imagePullSecrets for pulling images. If possible, this is the preferable and most portable route.

See the upstream kubernetes docs for this, kind does not require any special handling to use this.

If you already have the config file locally but would still like to use secrets, read through kubernetes’ docs for creating a secret from a file.

Pull to the Host and Side-Load

kind can load an image from the host with the kind load ... commands. If you configure your host with credentials to pull the desired image(s) and then load them to the nodes you can avoid needing to authenticate on the nodes.

Add Credentials to the Nodes

Generally the upstream docs for using a private registry apply, with kind there are two options for this.

Mount a Config File to Each Node

If you pre-create a docker config.json containing credential(s) on the host you can mount it to each kind node.

Assuming your file is at /path/to/my/secret.json, the kind config would be:

kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 nodes: - role: control-plane extraMounts: - containerPath: /var/lib/kubelet/config.json hostPath: /path/to/my/secret.json

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  extraMounts:
  - containerPath: /var/lib/kubelet/config.json
    hostPath: /path/to/my/secret.json

#!/bin/sh
set -o errexit
# desired cluster name; default is “kind”
KIND_CLUSTER_NAME=”${KIND_CLUSTER_NAME:-kind}”
# create a temp file for the docker config
echo “Creating temporary docker client config directory …”
DOCKER_CONFIG=$(mktemp -d)
export DOCKER_CONFIG
trap ‘echo “Removing ${DOCKER_CONFIG}/*” && rm -rf ${DOCKER_CONFIG:?}’ EXIT
echo “Creating a temporary config.json”
# This is to force the omission of credsStore, which is automatically
# created on supported system. With credsStore missing, “docker login”
# will store the password in the config.json file.
# https://docs.docker.com/engine/reference/commandline/login/#credentials-store
cat <<EOF >”${DOCKER_CONFIG}/config.json”
{
 “auths”: { “gcr.io”: {} }
}
EOF
# login to gcr in DOCKER_CONFIG using an access token
# https://cloud.google.com/container-registry/docs/advanced-authentication#access_token
echo “Logging in to GCR in temporary docker client config directory …”
gcloud auth print-access-token | \
  docker login -u oauth2accesstoken —password-stdin https://gcr.io
# setup credentials on each node
echo “Moving credentials to kind cluster name=’${KIND_CLUSTER_NAME}’ nodes …”
for node in $(kind get nodes —name “${KIND_CLUSTER_NAME}”); do
  # the -oname format is kind/name (so node/name) we just want name
  node_name=${node#node/}
  # copy the config to where kubelet will look
  docker cp “${DOCKER_CONFIG}/config.json” “${node_name}:/var/lib/kubelet/config.json”
  # restart kubelet to pick up the config
  docker exec “${node_name}” systemctl restart kubelet.service
done
echo “Done!”