The most important Docker Compose properties

Do you want to have the most important properties of docker-compose in one place? Here you get a short overview of the properties and additionally a simple cheat sheet that you can use!

In this post, I will explain the different sections and properties of the cheat sheet that you can download here!

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File structure

This shows the basic structure of every docker-compose file. With the basic settings that can be a docker-compose.yml or a docker-compose.override.yml.

services:
     container1:
         properties: values

     container2:
         properties: values

networks:
     network:

volumes:
     volume:

YML Types

Each compose property has one or multiple possible types. The different possibilities are a basic key:value, an array, or a dictionary.

Value

key: value

Array

key:
     - value
     - value

Dictionary

master:
     key: value
     key: value

Properties

There are a few possible properties that you can use in a container. The most important ones are listed here with a short description, the type, and an example of how to use it.

build (value)

Build an image with the specified name by using the Dockerfile in the specified directory.

container:
     build: ./path
     image: image-name

image (value)

Use an image that is on the system or that can be downloaded from the docker hub.

image: image-name

container_name (value)

Specify the container name, that the container will be accessible with.

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container_name: name

volumes (array)

Create container volumes to persist data and to make certain directories available on the host system.

volumes:
     - /path/to/host-dir:/path/to/container-dir

command (value)

Overwrite the start command of the container.

command: command-to-execute

environment (dictionary/array)

Define environment variables to use inside of the container.

environment:
     KEY: VALUE
---
environment:
     - KEY=VALUE

env_file (dictionary/array)

Define environment variables inside a .env file to use inside of the container. The environment variables specified in the file will override the variables specified in the environment property.

env_file: .env
---
env_file:
     - .env

restart (value)

Specify a restart rule for the container. (no, always, on-failure, unless-stopped)

restart: unless-stopped

networks (array)

Define the networks a container should be attached to.

networks:
     - network-name

ports (array)

Define ports to expose to other containers and the host system.

ports:
     - "9999:9999"

expose (array)

Define ports to expose only to other containers.

expose:
     - "9999"

network_mode (value)

Set the network driver for the container. (bridge, host, none, service:[service name], container:[container name/id])

network_mode: host

depends_on (array)

Specify the build, start and stop order of the container.

depends_on:
     - container-name

Other

idle container

Define the command, to make the container do nothing! The container will not stop and it is possible to enter it without problems. Mostly only needed for debugging.

command: tail -f /dev/null

named volumes

Create named volumes that can be used in the volumes property. More information.

services:
   container:
     image: image-name
     volumes:
       - data-volume:/path/to/dir

volumes:
   data-volume:

networks

Create new networks that can be used in the network’s property. It will specify the name and the network driver. More information.

networks:
   frontend:
     driver: bridge

I hope you can make use of this collection of the most important docker-compose properties. If you think I missed something, you have some questions, or just feedback comment below or send me an email at mail@programonaut.com!