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Registries configuration file

You can add registries by specifying them in a registries.yaml and mounting them at creation time: k3d cluster create mycluster --volume "/home/YOU/my-registries.yaml:/etc/rancher/k3s/registries.yaml".

This file is a regular k3s registries configuration file, and looks like this:


In this example, an image with a name like would be pulled from the registry running at

Note well there is an important limitation: this configuration file will only work with k3s >= v0.10.0. It will fail silently with previous versions of k3s, but you find in the section below an alternative solution.

This file can also be used for providing additional information necessary for accessing some registries, like authentication and certificates.

Authenticated registries

When using authenticated registries, we can add the username and password in a configs section in the registries.yaml, like this:


      username: aladin
      password: abracadabra

Secure registries

When using secure registries, the registries.yaml file must include information about the certificates. For example, if you want to use images from the secure registry running at, you must first download a CA file valid for that server and store it in some well-known directory like ${HOME}/.k3d/my-company-root.pem.

Then you have to mount the CA file in some directory in the nodes in the cluster and include that mounted file in a configs section in the registries.yaml file. For example, if we mount the CA file in /etc/ssl/certs/my-company-root.pem, the registries.yaml will look like:


      # we will mount "my-company-root.pem" in the /etc/ssl/certs/ directory.
      ca_file: "/etc/ssl/certs/my-company-root.pem"

Finally, we can create the cluster, mounting the CA file in the path we specified in ca_file:

k3d cluster create --volume "${HOME}/.k3d/my-registries.yaml:/etc/rancher/k3s/registries.yaml" --volume "${HOME}/.k3d/my-company-root.pem:/etc/ssl/certs/my-company-root.pem"

Using a local registry

Using the k3d registry

Not ported yet

The k3d-managed registry has not yet been ported from v1.x to v3.x

Using your own local registry

You can start your own local registry it with some docker commands, like:

docker volume create local_registry
docker container run -d --name registry.localhost -v local_registry:/var/lib/registry --restart always -p 5000:5000 registry:2

These commands will start your registry in registry.localhost:5000. In order to push to this registry, you will need to make it accessible as described in the next section. Once your registry is up and running, we will need to add it to your registries.yaml configuration file. Finally, you have to connect the registry network to the k3d cluster network: docker network connect k3d-k3s-default registry.localhost. And then you can test your local registry.

Pushing to your local registry address

As per the guide above, the registry will be available at registry.localhost:5000. All the nodes in your k3d cluster can resolve this hostname (thanks to the DNS server provided by the Docker daemon) but, in order to be able to push to this registry, this hostname also has to be resolved by your host.

Luckily (for Linux users), NSS-myhostname ships with many Linux distributions and should resolve *.localhost automatically to
Otherwise, it’s installable using sudo apt install libnss-myhostname.

If it’s not the case, you can add an entry in your /etc/hosts file like this: registry.localhost

Once again, this will only work with k3s >= v0.10.0 (see the some sections below when using k3s <= v0.9.1)

Testing your registry

You should test that you can

  • push to your registry from your local development machine.
  • use images from that registry in Deployments in your k3d cluster.

We will verify these two things for a local registry (located at registry.localhost:5000) running in your development machine. Things would be basically the same for checking an external registry, but some additional configuration could be necessary in your local machine when using an authenticated or secure registry (please refer to Docker’s documentation for this).

First, we can download some image (like nginx) and push it to our local registry with:

```shell script docker pull nginx:latest docker tag nginx:latest registry.localhost:5000/nginx:latest docker push registry.localhost:5000/nginx:latest

Then we can deploy a pod referencing this image to your cluster:

```shell script
cat <<EOF | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
  name: nginx-test-registry
    app: nginx-test-registry
  replicas: 1
      app: nginx-test-registry
        app: nginx-test-registry
      - name: nginx-test-registry
        image: registry.localhost:5000/nginx:latest
        - containerPort: 80

Then you should check that the pod is running with kubectl get pods -l "app=nginx-test-registry".

Configuring registries for k3s <= v0.9.1

k3s servers below v0.9.1 do not recognize the registries.yaml file as described in the in the beginning, so you will need to embed the contents of that file in a containerd configuration file. You will have to create your own containerd configuration file at some well-known path like ${HOME}/.k3d/config.toml.tmpl, like this:

# Original section: no changes
path = "{{ .NodeConfig.Containerd.Opt }}"
stream_server_address = "{{ .NodeConfig.AgentConfig.NodeName }}"
stream_server_port = "10010"
{{- if .IsRunningInUserNS }}
disable_cgroup = true
disable_apparmor = true
restrict_oom_score_adj = true
{{ end -}}
{{- if .NodeConfig.AgentConfig.PauseImage }}
sandbox_image = "{{ .NodeConfig.AgentConfig.PauseImage }}"
{{ end -}}
{{- if not .NodeConfig.NoFlannel }}
    bin_dir = "{{ .NodeConfig.AgentConfig.CNIBinDir }}"
    conf_dir = "{{ .NodeConfig.AgentConfig.CNIConfDir }}"
{{ end -}}

# Added section: additional registries and the endpoints
    endpoint = ["http://registry.localhost:5000"]

and then mount it at /var/lib/rancher/k3s/agent/etc/containerd/config.toml.tmpl (where containerd in your k3d nodes will load it) when creating the k3d cluster:

k3d cluster create mycluster \
    --volume ${HOME}/.k3d/config.toml.tmpl:/var/lib/rancher/k3s/agent/etc/containerd/config.toml.tmpl

Last update: October 2, 2020