kubedock

packaged by Chainguard

Chainguard Container for kubedock

Minimal Docker API implementation that orchestrates containers on Kubernetes.

Chainguard Containers are regularly-updated, secure-by-default container images.

Download this Container Image

For those with access, this container image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/kubedock:latest

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard Registry.

Compatibility Notes

The Chainguard kubedock container image is comparable to the upstream joyrex2001/kubedock image. As with other Chainguard Containers, this image uses Wolfi as the base OS instead of BusyBox, while shipping the same kubedock binary built from the upstream source.

Kubedock is designed for short-lived ephemeral workloads like running integration tests with Testcontainers or docker-compose on a Kubernetes cluster. It is not intended for production container orchestration.

Getting Started

Kubedock requires access to a Kubernetes API server to orchestrate pods. When running inside a Kubernetes cluster, it uses the pod's service account by default.

Deploy kubedock as a Deployment with a ServiceAccount that has permission to manage pods, services, and configmaps:

cat > kubedock.yaml <<EOF
apiVersion: v1
kind: ServiceAccount
metadata:
  name: kubedock
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: kubedock
rules:
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["create", "get", "list", "delete", "watch"]
  - apiGroups: [""]
    resources: ["pods/log"]
    verbs: ["list", "get"]
  - apiGroups: [""]
    resources: ["pods/exec"]
    verbs: ["create"]
  - apiGroups: [""]
    resources: ["services"]
    verbs: ["create", "get", "list", "delete"]
  - apiGroups: [""]
    resources: ["configmaps"]
    verbs: ["create", "get", "list", "delete"]
  ## optional permissions (depending on kubedock use)
  # - apiGroups: ["coordination.k8s.io"]
  #   resources: ["leases"]
  #   verbs: ["create", "get", "update"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: kubedock
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: kubedock
subjects:
- kind: ServiceAccount
  name: kubedock
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: kubedock
spec:
  replicas: 1
  selector:
    matchLabels:
      app: kubedock
  template:
    metadata:
      labels:
        app: kubedock
    spec:
      serviceAccountName: kubedock
      containers:
      - name: kubedock
        image: cgr.dev/ORGANIZATION/kubedock:latest
        args: ["server", "--listen-addr=:2475", "--reverse-proxy"]
        ports:
        - containerPort: 2475
---
apiVersion: v1
kind: Service
metadata:
  name: kubedock
spec:
  selector:
    app: kubedock
  ports:
  - port: 2475
    targetPort: 2475
EOF

Apply the manifests:

kubectl apply -f kubedock.yaml

Point a Docker client at the kubedock service by setting DOCKER_HOST:

export DOCKER_HOST=tcp://kubedock:2475
docker version

Configuration

Kubedock is configured via command-line flags passed to the server subcommand. Common flags include:

• --listen-addr: The address for the Docker API server to listen on. Default is :2475.
• --kubeconfig: Path to a kubeconfig file. Defaults to the in-cluster service account when empty.
• --namespace: Kubernetes namespace where orchestrated pods are created.

Refer to the kubedock configuration reference for the full list of flags and environment variables.

Documentation and Resources

• kubedock GitHub Repository
• kubedock Configuration Guide

What are Chainguard Containers?

Chainguard's free tier of Starter container images are built with Wolfi, our minimal Linux undistro.

All other Chainguard Containers are built with Chainguard OS, Chainguard's minimal Linux operating system designed to produce container images that meet the requirements of a more secure software supply chain.

The main features of Chainguard Containers include:

• Minimal design, without unnecessary software bloat
• Daily builds to ensure container images are up-to-date with available security patches
• High quality build-time SBOMs attesting to the provenance of all artifacts within the image
• Verifiable signatures provided by Sigstore
• Reproducible builds with Cosign and apko (read more about reproducibility)

For cases where you need container images with shells and package managers to build or debug, most Chainguard Containers come paired with a development, or -dev, variant.

In all other cases, including Chainguard Containers tagged as :latest or with a specific version number, the container images include only an open-source application and its runtime dependencies. These minimal container images typically do not contain a shell or package manager.

Although the -dev container image variants have similar security features as their more minimal versions, they include additional software that is typically not necessary in production environments. We recommend using multi-stage builds to copy artifacts from the -dev variant into a more minimal production image.

Need additional packages?

To improve security, Chainguard Containers include only essential dependencies. Need more packages? Chainguard customers can use Custom Assembly to add packages, either through the Console, chainctl, or API.

To use Custom Assembly in the Chainguard Console: navigate to the image you'd like to customize in your Organization's list of images, and click on the Customize image button at the top of the page.

Learn More

Refer to our Chainguard Containers documentation on Chainguard Academy. Chainguard also offers VMs and Libraries — contact us for access.

Trademarks

This software listing is packaged by Chainguard. The trademarks set forth in this offering are owned by their respective companies, and use of them does not imply any affiliation, sponsorship, or endorsement by such companies.