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Tools

docker compose

Docker Compose is a tool for running multi-container applications on Docker defined using the Compose file format. A Compose file is used to define how one or more containers that make up your application are configured. Once you have a Compose file, you can create and start your application with a single command: docker compose up, A commpose file defines your application, a componse file has several services, each service is one container!

You can imagine docker compose as a wrapper for docker command but supports operating containers at application level, meaning start/stop application, no matter how many container it has, it just makes the work earlier.

docker compose vs docker-compose: docker-compose is orignal tool this the target mentioned above, but docker-compose is written in Python while most Docker developments are in Go, so they decided to recreate docker compose project in Go with the same and more features, docker compose will eventually replace docker-compose, but no timeline for that yet, so if you’r new to this, use docker compose.

Install the docker compose, please refer to guide to install docker compose

Usage

when you run docker compose command, it scans a file named docker-compose.yml from current directory if not specified by user.

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Usage:  docker compose [OPTIONS] COMMAND

Define and run multi-container applications with Docker.

Options:
      --dry-run                    Execute command in dry run mode
  -f, --file stringArray           Compose configuration files
  ...

Commands:
  build       Build or rebuild services
  config      Parse, resolve and render compose file in canonical format
  cp          Copy files/folders between a service container and the local filesystem
  create      Creates containers for a service.
  down        Stop and remove containers, networks
  events      Receive real time events from containers.
  exec        Execute a command in a running container.
  images      List images used by the created containers
  kill        Force stop service containers.
  logs        View output from containers
  ls          List running compose projects
  pause       Pause services
  port        Print the public port for a port binding.
  ps          List containers
  pull        Pull service images
  push        Push service images
  restart     Restart service containers
  rm          Removes stopped service containers
  run         Run a one-off command on a service.
  start       Start services
  stop        Stop services
  top         Display the running processes
  unpause     Unpause services
  up          Create and start containers
  version     Show the Docker Compose version information

docker-compose.yml example

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version: '2'
services:
  app:
    image: node:latest
    container_name: app_main
    restart: always
    command: sh -c "yarn install && yarn start"
    ports:
      - 8000:8000
    working_dir: /app
    volumes:
      - ./:/app
    environment:
      MYSQL_HOST: localhost
      MYSQL_USER: root
      MYSQL_PASSWORD:
      MYSQL_DB: test
  mongo:
    image: mongo
    container_name: app_mongo
    restart: always
    ports:
      - 27017:27017
    volumes:
      - ~/mongo:/data/db
volumes:
  mongodb:
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$ls
docker-compose.yml  Dockerfile
$cat Dockerfile
FROM hello-world

$cat docker-compose.yml
version: '2'
services:
  hello_world:
    # build this container from image directly
    image: hello-world
  hello-world-local:
    # build this container from Dockerfile
    build:
      context: .

$docker compose ls -a
NAME                STATUS              CONFIG FILES
compose             exited(2)           /tmp/compose/docker-compose.yml
$docker compose ps -a
NAME                          IMAGE                       COMMAND             SERVICE             CREATED              STATUS                          PORTS
compose-hello-world-local-1   compose-hello-world-local   "/hello"            hello-world-local   About a minute ago   Exited (0) About a minute ago   
compose-hello_world-1         hello-world                 "/hello"            hello_world         About a minute ago   Exited (0) About a minute ago

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