筆記線上課程 Docker Mastery Section 6內容


Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a YAML file to configure your application’s services. Then, with a single command, you create and start all the services from your configuration.

“Compose是用來管理多個container的工具，可以透過YAML檔案來設定Service，利用指令就可以建立以及啟動服務”

by-官方文件說明

Udemy- Docker mastery Note

Docker Compose and The-docker-compose.yml File

之前要啟動container時，都要一個一個下docker container run -p xx:xx -v xxxx imagename blabla，在寫volume的folder時可能會打錯。 docker compose工具的產生可以解決這件事!


  • why: configure relationships between containers
  • why: save our docker container run settings in easy-to-read file
  • why: create one-liner developer environment startups
  • comprised of 2 separate but related things
    • YAML formatted file that describes our solution options for
      • containers
      • networks
      • volumes
    • a CLI tool docker-compose used for local dev/test automation with those YAML files

為什麼?

  • 用來配置多個container
  • 讓啟動container時要傳入的參數好讀好懂?)
  • 利用一行指令可以迅速建立所需的環境

怎麼使用?

- YAML檔案來定義container, network, volume
- yml檔案中定義的服務，可以透過`docker-compose`指令來執行啟動、停止


docker-compose.yml

  • compose YAML format has it’s own version:1,2,2.1,3,3.1
  • YAML file can be used with docker-compose command for local docker container or..
  • with docker directly in production with Swarm
  • docker-compose --help
  • docker-compose.yml is default filename, but any can b used with docker-compose -f

講者提供的template.yml

version: '3.1'  # if no version is specified then v1 is assumed. Recommend v2 minimum

services:  # containers. same as docker run
  servicename: # a friendly name. this is also DNS name inside network
    image: # Optional if you use build:
    command: # Optional, replace the default CMD specified by the image
    environment: # Optional, same as -e in docker run
    volumes: # Optional, same as -v in docker run
  servicename2:

volumes: # Optional, same as docker volume create

networks: # Optional, same as docker network create

實際yml:

version: '2'

# same as 
# docker run -p 80:4000 -v $(pwd):/site bretfisher/jekyll-serve

services:
  jekyll:
    image: bretfisher/jekyll-serve
    volumes:
      - .:/site
    ports:
      - '80:4000'


version: '2'

services:

  wordpress:
    image: wordpress
    ports:
      - 8080:80
    environment:
      WORDPRESS_DB_HOST: mysql
      WORDPRESS_DB_NAME: wordpress
      WORDPRESS_DB_USER: example
      WORDPRESS_DB_PASSWORD: examplePW
    volumes:
      - ./wordpress-data:/var/www/html

  mysql:
    image: mariadb
    environment:
      MYSQL_ROOT_PASSWORD: examplerootPW
      MYSQL_DATABASE: wordpress
      MYSQL_USER: example
      MYSQL_PASSWORD: examplePW
    volumes:
      - mysql-data:/var/lib/mysql

volumes:
  mysql-data:


Basic Compose Commands

docker-comppose CLI

  • CLI tool comes with Docker for windows/mac, but separate download for linux
  • not a production-grade tool but ideal for local development and test
  • two most common commands are
    • docker-compose up-setup volumes/networks and start all containers
    • docker-compose down-stop all containers and remove cont/vol/net
  • if all your projects had a Dockefile and docker-compose.yml, then “new developer onboarding” would be:
    • git clone github.com/some/software
    • docker-compose up


啟動兩個container，nginx和apache

nginx當proxy (守門員), apache當web server(提供內容者)

version: '3'

services:
  proxy:
    image: nginx:1.13 # this will use the latest version of 1.13.x
    ports:
      - '80:80' # expose 80 on host and sent to 80 in container
    volumes:
      - ./nginx.conf:/etc/nginx/conf.d/default.conf:ro
  web:
    image: httpd  # this will use httpd:latest

指令沒有下 -d ，可以直接從log看到請求

docker-compose up


小結

在windows中使用docker toolbox，docker是Run在虛擬機上，有時候遇到volume掛不上，可以試試看先連進docker內。

docker-machine ls

docker-machine ssh xxx

ssh docker machine


參考圖文&文章

Overview of Docker Compose

利用 Docker Compose 管理多個容器