Private Docker Registry

The docker-registry charm facilitates the storage and distribution of container images. Include this in a Kubernetes deployment to provide images to cluster components without requiring access to public registries. See https://docs.docker.com/registry/ for details.

Deploy

The registry is deployed as a stand-alone application. Many deployment scenarios are described in the charm readme. The most common scenario for Kubernetes integration is to configure a registry with TLS and basic (htpasswd) authentication enabled.

If needed, consult the quickstart guide to install Charmed Kubernetes. Then deploy and configure docker-registry as follows.

juju deploy cs:~containers/docker-registry
juju add-relation docker-registry easyrsa:client
juju config docker-registry \
  auth-basic-user='admin' \
  auth-basic-password='password'

Custom Certificates

Relating docker-registry to easyrsa above will generate new TLS data to support secure communication with the registry. Alternatively, custom TLS data may be provided as base64-encoded config options to the charm:

juju config docker-registry \
  tls-ca-blob=$(base64 /path/to/ca) \
  tls-cert-blob=$(base64 /path/to/cert) \
  tls-key-blob=$(base64 /path/to/key)

Proxied Registry

Advanced networking or highly available deployment scenarios may require multiple docker-registry units to be deployed behind a proxy. In this case, the network information of the proxy will be shared with the container runtime units when the registry is related.

Note: SSL pass-thru is supported between 'docker-registry' and 'haproxy', though manual configuration is required. The recommended approach for a proxied registry is to disable SSL on 'docker-registry' prior to relating it to 'haproxy'. Consult the 'docker-registry' charm readme if SSL is required in a proxied environment.

The environment described in the Deploy section above can be adjusted to create a highly available registry as follows:

juju deploy haproxy
juju add-unit docker-registry
juju remove-relation docker-registry easyrsa:client
juju add-relation docker-registry haproxy:reverseproxy

Note: With multiple registry units deployed, the proxy relation allows for a highly available deployment. Load balancing across multiple registry units is not supported.

Verify

Make note of the registry address. By default, this address is only accessible within the deployment model. See the charm readme for host and proxy configuration options if desired.

export IP=`juju run --unit docker-registry/0 'network-get website --ingress-address'`
export PORT=`juju config docker-registry registry-port`
export REGISTRY=$IP:$PORT

Verify basic authentication is working:

juju run --unit docker-registry/0 "docker login -u admin -p password $REGISTRY"
Login Succeeded
...

Connecting to a Charmed Kubernetes cluster

Relate the deployed registry to the appropriate container runtime for your cluster. This configures the runtime with authentication, proxy, and/or TLS data from the registry.

Containerd

juju add-relation docker-registry containerd

Docker

juju add-relation docker-registry docker

Kubernetes images

A list of images that may be used by Charmed Kubernetes can be found in the container-images.txt document. This is a comprehensive list sorted by release; not all images are required for all deployments. Take note of the images required by your deployment that will need to be hosted in your private registry.

Hosting images

To make an image available in the deployed registry, it must be tagged and pushed. As an example, push the defaultbackend-amd64 image to docker-registry:

juju run-action docker-registry/0 \
  push \
  image=k8s.gcr.io/defaultbackend-amd64:1.5 \
  tag=$REGISTRY/defaultbackend-amd64:1.5 \
  --wait
...
  results:
    outcome: success
    raw: pushed 172.31.28.74:5000/k8s.gcr.io/defaultbackend-amd64:1.5
  status: completed
...

The above procedure should be repeated for all required images.

Using hosted images

The image registry used by Charmed Kubernetes is controlled by a kubernetes-master config option. Configure kubernetes-master to use your private registry as follows:

juju config kubernetes-master image-registry=$REGISTRY

We appreciate your feedback on the documentation. You can edit this page or file a bug here.