Generate configuration files based on docker state changes.

pip install docker-cab



docker-cab is a small python program that waits for change notifications from your docker daemon and regenerates an nginx configuration file each time this happens. It autogenerates reverse-proxy entries for docker containers that are "published".

To publish a container, three criterias must be fulfilled:

  1. It must be part of the frontnet-network.
  2. An environment variable named VIRTUAL_HOST must be present.
  3. An SSL certificate chain with a key must be installed (currently, SSL is mandatory with docker-cab, not optional).

Trying it out

You can try docker-cab right now (an automated build is available at

docker run -v /var/run/docker.sock:/var/run/docker.sock --rm -it docker-cab list

Since there is most likely no frontnet network configured, the output will be empty. See Deploying for a way to configure containers in a way that makes them discoverable by docker-cab.


  1. Create a network named frontnet on your docker host/swarm or desktop by running:

    docker network create frontnet
  2. Run docker-compose to start the nginx server (see cabfront/docker-compose.yml):

    docker-compose -d

    When testing locally, omit the -d for testing.

At this point, docker-cab is ready. If you wish to add a site with a domain name, e.g. localhost, these are the steps required:

  1. Copy localhost.crt and localhost.key to /docker-volumes/cabfront-certs. You may need self-signed certificates when testing locally.

  2. Start the app container, ensuring that it is part of the frontnet network and has the VIRTUAL_HOST environment variable set. Example:

    docker run --net=frontnet -e VIRTUAL_HOST=localfoo training/webapp