====== docker & docker-compose - Cheatsheet ======

**Tags:** #docker #dockercompose #cheatsheet

**Last Reviewed:** 16/08/2024

Usefull commands for docker and docker-compose

===== Quick Reference =====

^Command^Purpose|
|docker-compose up -d|Starts the Container and dettach (so you have your bash prompt back)|
|docker-compose down|Stops the Container|
|docker-compose ps|Checks the status of the Container|
|docker-exec -ti <container-name> /bin/bash|Opens a Shell Prompt inside a Container (so you can troubleshoot)|
|docker save <image> > file.tar|Saves an Image to a Tar file \\ Eg.: docker save nginx:latest > nginx_backup.tar|
|docker load < file.tar|Loads a Tar file as an Image|
|docker stop $(docker ps -a -q)|Stops all Containers. You can use "rm" instead of "stop" to remove them!|
|<code bash>
docker build --tag <tag> .


</code>       |To be run from the directory where "dockerfile" lives. Will create an Image with the tag provided. Eg.: docker build –tag tornscrapper:0.1  |
|<code>
docker images -a | grep none | awk '{ print $3; }' | xargs docker rmi

</code>       |Delete dangling images and / or images that have a "none" tag. \\ Might be helpful if "docker image prune" doesn't remove those.|

===== Cheatsheet  =====

==== Commands ====
<code>

docker compose version
docker compose config
docker compose start
docker compose stop
docker compose restart
docker compose run
docker compose create
docker compose attach
docker compose pause
docker compose unpause
docker compose wait
docker compose up
docker compose down
docker compose ps
docker compose top
docker compose events
docker compose logs
docker compose images
docker compose build
docker compose push
docker compose cp
docker compose exec

</code>
==== Building ====

<code>
web:
  # build from Dockerfile
  build: .
  args:     # Add build arguments
    APP_HOME: app
  # build from custom Dockerfile
  build:
    context: ./dir
    dockerfile: Dockerfile.dev
  # build from image
  image: ubuntu
  image: ubuntu:14.04
  image: tutum/influxdb
  image: example-registry:4000/postgresql
  image: a4bc65fd

</code>
==== Ports ====

<code>
ports:
  - "3000"
  - "8000:80"  # host:container
# expose ports to linked services (not to host)
expose: ["3000"]

</code>
==== Environment Variables ====

<code>
# environment vars
environment:
  RACK_ENV: development
environment:
  - RACK_ENV=development
# environment vars from file
env_file: .env
env_file: [.env, .development.env]

</code>
==== Dependencies ====

<code>
# makes the `db` service available as the hostname `database`
# (implies depends_on)
links:
  - db:database
  - redis
# make sure `db` is alive before starting
depends_on:
  - db
# make sure `db` is healthy before starting
# and db-init completed without failure
depends_on:
  db:
    condition: service_healthy
  db-init:
    condition: service_completed_successfully

</code>
==== Other Options ====

<code>
# make this service extend another
extends:
  file: common.yml  # optional
  service: webapp
volumes:
  - /var/lib/mysql
  - ./_data:/var/lib/mysql
# automatically restart container
restart: unless-stopped
# always, on-failure, no (default)

</code>
===== Advanced Features =====

==== Labels ====

<code>
services:
  web:
    labels:
      com.example.description: "Accounting web app"

</code>
==== DNS Servers ====

<code>
services:
  web:
    dns: 8.8.8.8
    dns:
      - 8.8.8.8
      - 8.8.4.4

</code>
==== Devices ====

<code>
services:
  web:
    devices:
    - "/dev/ttyUSB0:/dev/ttyUSB0"

</code>
==== Healthcheck ====

<code>
# declare service healthy when `test` command succeeds
healthcheck:
  test: ["CMD", "curl", "-f", "http://localhost"]
  interval: 1m30s
  timeout: 10s
  retries: 3
  start_period: 40s

</code>
==== User ====

<code>
# specifying user
user: root
# specifying both user and group with ids
user: 0:0

</code>