在 docker-compose 中创建一个全局变量 od“extra_hosts”

Question

假设我在 docker-compose 中有十个服务，每个服务都需要相同的 extra_hosts 和四个记录。我想定义一次 extra_hosts 并仅将其包含到每个服务中。

是否可以？

version: '3.7'
services:

  web:
    build:
      context: ./apache
      dockerfile: dockerfile_apache2
    image: debian:latest
    container_name: hsthttp1
    extra_hosts:
     - "somehost1:162.242.195.82"
     - "somehost2:162.242.195.83"
     - "somehost3:162.242.195.84"
     - "somehost4:162.242.195.85"
  web2:
    build:
      context: ./apache
      dockerfile: dockerfile_apache2
    image: debian:latest
    container_name: hsthttp2
    extra_hosts:
     - "somehost1:162.242.195.82"
     - "somehost2:162.242.195.83"
     - "somehost3:162.242.195.84"
     - "somehost4:162.242.195.85"
  web3:
    build:
      context: ./apache
      dockerfile: dockerfile_apache2
    image: debian:latest
    container_name: hsthttp3
    extra_hosts:
     - "somehost1:162.242.195.82"
     - "somehost2:162.242.195.83"
     - "somehost3:162.242.195.84"
     - "somehost4:162.242.195.85"

Answer 1

是的，从 compose 版本 3.4 开始，可以使用扩展字段来定义可重用的片段：

根据您的情况，您可以使用下一步：

docker-compose.yaml：

version: '3.7'

x-extra_hosts:
  &default-extra_hosts
  - "somehost1:162.242.195.82"
  - "somehost2:162.242.195.83"
  - "somehost3:162.242.195.84"
  - "somehost4:162.242.195.85"

services:
  web:
    image: debian:latest
    container_name: hsthttp1
    extra_hosts: *default-extra_hosts
  web2:
    image: debian:latest
    container_name: hsthttp2
    extra_hosts: *default-extra_hosts
  web3:
    image: debian:latest
    container_name: hsthttp3
    extra_hosts: *default-extra_hosts

上面，我们定义了一个全局变量&default-extra_hosts，稍后我们可以在每个服务中引用它*default-extra_hosts。

您可以使用docker-compose config以下方法快速检查效果：

shubuntu1@shubuntu1:~/try$ docker-compose config
services:
  web:
    container_name: hsthttp1
    extra_hosts:
    - somehost1:162.242.195.82
    - somehost2:162.242.195.83
    - somehost3:162.242.195.84
    - somehost4:162.242.195.85
    image: debian:latest
  web2:
    container_name: hsthttp2
    extra_hosts:
    - somehost1:162.242.195.82
    - somehost2:162.242.195.83
    - somehost3:162.242.195.84
    - somehost4:162.242.195.85
    image: debian:latest
  web3:
    container_name: hsthttp3
    extra_hosts:
    - somehost1:162.242.195.82
    - somehost2:162.242.195.83
    - somehost3:162.242.195.84
    - somehost4:162.242.195.85
    image: debian:latest
version: '3.7'