Docker Compose Quick Start & Usage

Docker Compose is a tool that can centrally manage multiple Docker containers. We describe the installation method as a way to start it, and the main commands etc. as a usage.
The overview of Docker Compose will be described in another knowledge.
To use Docker Compose, you also need Docker itself. How to get started with Docker is described below.

• Docker Quick Start

Docker Compose installation

• Access the Docker Compose repository page at the following URL on GitHub and check the version you want to install.
  • https://github.com/docker/compose/releases
• Change the version part of the following command (after “~download/”) to the version you want to install, and execute the command. Docker Compose is downloaded by this command.
  • In the following example, Docker Compose “1.22.0” is downloaded and saved under “/usr/local/bin/” with the file name “docker-compose”.

$ sudo curl -L https://github.com/docker/compose/releases/download/1.22.0/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose

• The above is an executable binary, so just download it and the installation will be complete.
• Give execute permission to this file.

$ sudo chmod +x /usr/local/bin/docker-compose

• This completes the installation. Make sure Docker Compose is available.

$ docker-compose --version
docker-compose version 1.22.0, build f46880fe

Compose file

• Create a Compose file with the name “docker-compose.yml” and copy and save the following.
  • Below is a Compose file that allows you to download the latest version images of Ubuntu and CentOS from Docker Hub, create a container, and start it.
    • The following “depends_on” setting is set to start Ubuntu before CentOS.
    • If “restart: always” is set, the container will be restarted automatically if each container is stopped due to an error or other reason.
    • However, “depends_on” and “restart: always” do not work together. When the container is started using Docker Compose, the start order is controlled by “depends_on”, but if the container is stopped due to a failure etc. and automatically restarted by “restart: always”, the start order is not considered.

version: '3'

services:
  ubuntu01:
    image: ubuntu:latest
    restart: always

  centos01:
    depends_on:
      - ubuntu01
    image: centos:latest
    restart: always

Docker Compose main commands

Execute the following Docker Compose command in the directory where “docker-compose.yml” is saved.

• Download the image, create and launch the container with Docker Compose.
  • With the “-d” option, the container goes into detach mode and starts in the background.
  • If the target image already exists, the image download is skipped and the container is created first.
  • If there is already a container, container creation is skipped and only container startup is performed.

$ docker-compose up -d

• By default, the Compose file uses “docker-compose.yml” in the current directory, but if you want to specify the YAML file name to use, use the following command.
  • In the example below, “xxxxxxxxxxx.yml” is used.

$ docker-compose -f xxxxxxxxxxx.yml up -d

• If you want to log in to the container after startup, use the Docker command.
  • Docker Usage & Entity
• Stop the containers.

$ docker-compose stop

• Start the containers.

$ docker-compose start

• Retart the containers.

$ docker-compose restart

• Check the status of the containers.

$ docker-compose ps

• Stop the containers and delete them.

$ docker-compose down

• Stop the containers and delete the containers and images.

$ docker-compose down --rmi all

• If you are using Docker Volume, check the Vloumes you are using.

$ docker volume ls

• Delete the Docker Volume with the specified Volume Name.
  • In the following, the Volume whose Volume Name is xxxxxxxxxxxx is deleted.

$ docker volume rm xxxxxxxxxxxx