docker.md

Docker Tidbits

Inspect Docker VM Contents on Docker for Mac

With Docker Machine it was possible to SSH into the VM (docker-machine ssh) and inspect Docker volume contents, etc. This is still possible on the more modern Docker for Mac, albeit in a roundabout way:

docker run -it --privileged --pid=host ubuntu nsenter -t 1 -m -u -n -i sh

Source: https://gist.github.com/BretFisher/5e1a0c7bcca4c735e716abf62afad389

Build Unminimized Ubuntu Docker Image w/ Timezone & Locale

FROM ubuntu:latest
SHELL ["bash", "-c"]
RUN ln -fs /usr/share/zoneinfo/America/Los_Angeles /etc/localtime
RUN apt-get update
RUN DEBIAN_FRONTEND=noninteractive apt-get install -y locales OTHER_DEPENDENCIES
RUN yes | unminimize
ARG LOCALE_UTF8=en_US.UTF-8
RUN locale-gen "${LOCALE_UTF8}"
ENV LC_ALL=${LOCALE_UTF8}

Simple Long-Running Docker Container

The Docker Compose configuration below can be spun up with docker-compose up and quickly gracefully terminate on Ctrl-C or equivalent.

version: '3'
services:
  main:
    image: ubuntu:latest
    tty: true
    command:
      - bash
      - --noprofile
      - --norc

Without tty: true, the bash entrypoint does not exit gracefully and ignores SIGTERM.

Prevent Docker Compose From Creating Default Network

By default, Docker Compose creates a default network for the project:

$ docker-compose up
[+] Running 2/0
 ⠿ Network project_default          Created
 ⠿ Container project-service        Created

To prevent this, edit docker-compose.yml to to put the service into bridged networking mode:

version: '3'
services:
  service:
    ...
    network_mode: bridge