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dockerdocker-composedockerfiledocker-in-docker
Patrick Fromberg
Patrick Fromberg

Reputation: 1397

How to execute a docker::dind docker image with a dedicated daemon.json configuration file

I have the following content in docker compose to spin up my docker:dind service

  dind:
    image: docker:dind
    container_name: dind
    privileged: true
    command: ['dockerd', '--iptables=false', '--config-file=/etc/docker/daemon.json']
    networks:
      isolated_network:
        ipv4_address: 172.16.0.4
    restart: always
    hostname: 'Dindy'
    volumes:
      - ./volumes/dind/config:/etc/docker
      - ./volumes/dind/var/lib/docker:/var/lib/docker

and that works for me, but it is not perfect. I have to configure the service by creating volume/dind/config/daemon.json first. This does not feel like the intended way.

So I tried to build with a docker file and copy the daemon in there.

FROM docker:dind
RUN mkdir /etc/docker
COPY ./daemon.json /etc/docker

That works after removing the mapping ./volumes/dind/config:/etc/docker in the docker-compose.json file, otherwise docker logs dind would say:

unable to configure the Docker daemon with file /etc/docker/daemon.json: open /etc/docker/daemon.json: no such file or directory

The missing volume mapping is ok, I do not need it any more. I am still puzzled why I need to remove it.

Anyhow, I have to create a new image via Dockerfile just to copy my daemon.json file. Or otherwise I have to populate the volumes directory with the daemon.json file.

Other suggestions how to solve this?

UPDATE maybe this solution is the best? Just found it after posting.

Upvotes: 0

Views: 149

Answers (1)

Patrick Fromberg
Patrick Fromberg

Reputation: 1397

I found a configs command in docker compose which does what I need. See documentation here

So my docker-compose.yml, the dind service, looks like this now, note the new configs: section:

  dind:
    image: docker:dind
    container_name: dind
    privileged: true
    command: ['dockerd', '--iptables=false', '--config-file=/etc/docker/daemon.json']
    networks:
      isolated_gitlab:
        ipv4_address: 172.16.0.4
    restart: always
    hostname: 'gitlab-dind'
    configs:
      - source: dind_daemon_json
        target: /etc/docker/daemon.json
    volumes:
      - ./volumes/dind/var/lib/docker:/var/lib/docker
. . . 
configs:
  dind_daemon_json:
    file: ./context/dind/daemon.json

Upvotes: 0

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