Docker.md

Use of Docker for this project

Configuration

There is both a Dockerfile for building the container images, and a docker-compose.yaml file for actually running them.

This means that you should definitely be using docker compose commands, not plain docker ones. You might have to install the Docker compose plugin in order to have the sub-command available.

Overriding configuration

For some things where you need custom configuration relevant to your Docker host you will not need to edit either Dockerfile or docker-compose.yaml, instead you can utilise a docker-composr.override.yaml file.

For example, to tweak the network configuration you might use:

version: '3'

networks:
  default:
    ipam:
      config:
        - subnet: 172.16.2.0/24
    driver_opts:
      # Must be no more than ppp0's MTU
      com.docker.network.driver.mtu: 1492

This nails the networking down to a specific subnet (rather than a random one chosen from the Docker host's range), and ensures the MTU is set appropriately for the upstream WAN link.

Using on Debian bullseye

This was all developed using docker.com's own Debian APT repository, starting with 20.10.17 versions.

If you try to use the Debian bullseye docker.io and docker-compose packages, which are based on version 1.25.0, things will likely either not work at all, or not as described in this document.

To set up the APT repository consult the upstream instructions.

Hints

Building the image

docker compose build

Starting and stopping the containers

After a build you will want:

docker compose up -d

To stop them:

docker compose stop

and then to start them again, without a rebuild:

docker compose start

Note that you can stop/start individual containers if desired.

Checking output logs

To check latest logs from all containers:

docker compose logs

Or if you only want a specific container:

1. docker compose ps - to get be sure of the container name, it's in the SERVICE column.
2. docker compose logs <container name>.