narwhal

narwhal provides a web interface for managing Docker instances. Specifically, it is built to host CTF challenge servers. narwhal is built with Falcon.

API documentation is available at https://blairsec.github.io/narwhal/.

Registry

Creating a registry for narwhal follows the standard procedure. First, pull the registry:2 image from Docker Hub.

Within the project directory, run:

λ touch docker-compose.yml
λ mkdir registry
λ mkdir auth
λ docker run --entrypoint htpasswd registry:2 -Bbn <user> <pass> > auth/htpasswd

Write to docker-compose.yml:

registry:
  restart: always
  image: registry:2
  ports:
    - 5000:5000
  environment:
    REGISTRY_AUTH: htpasswd
    REGISTRY_AUTH_HTPASSWD_PATH: /auth/htpasswd
    REGISTRY_AUTH_HTPASSWD_REALM: registry
    REGISTRY_STORAGE_DELETE_ENABLED: "true"
  volumes:
    - ./registry:/var/lib/registry
    - ./auth:/auth

On the server where narwhal is running, authenticate the Docker client with the registry.

Images

Since narwhal automates container creation, runtime flags must be provided in an image's label named options. They should be formatted as a JSON-encoded kwargs dictionary for the Docker Python SDK's run method.

Labels can be set within a Dockerfile:

LABEL options='{"ports": {"2222/tcp": 333}}'

narwhal will then expose port 2222 inside the container as port 3333 on the host. Note that the detached flag does not have to be provided.

An image corresponds to exactly one container. If more are necessary, consider using multiple tags that point to the same image.