docker - 在撰写文件版本3中挂载Windows主机目录

Question

我试图将docker-compose.yml从版本1升级到版本3。

有关的主要问题

volumes_from: To share a volume between services, 
define it using the top-level volumes option and 
reference it from each service that shares it using the 
service-level volumes option.

最简单的例子:

版本“1”

data:
  image: postgres:latest
  volumes:
    - ./pg_hba.conf/:/var/lib/postgresql/data/pg_hba.conf

postgres:
  restart: always
  image:  postgres:latest
  volumes_from:
    - data
  ports:
    - "5432:5432"

如果我正确理解，应转换为

version: "3"

services:
  db:
    image: postgres:latest
    restart: always
    volumes:
      - db-data:/var/lib/postgresql/data
    ports:
      - "5432:5432"
    networks:
      - appn

  networks:
    appn:

  volumes:
    db-data:?

问题:现在如何在顶级卷选项中如何将的相对路径设置为文件夹中的文件夹“example_folder”从托管到到“db-data” ？

Answer 1

在这种情况下，您可能会考虑不使用volumes_from。

如docker 1.13 issue在此Sebastiaan van Stijn (thaJeztah)中所述:

The volumes_from is basically a "lazy" way to copy volume definitions from one container to another, so;

docker run -d --name one -v myvolume:/foo image-one

docker run -d --volumes-from=one image-two

Is the same as running;

docker run -d --name one -v myvolume:/foo image-one
docker run -d --name two -v myvolume:/foo image-two

If you are deploying to AWS you should not use bind-mounts, but use named volumes instead (as in my example above), for example;

version: "3.0"

services:
  db:
    image: nginx
    volumes:
      - uploads-data:/usr/share/nginx/html/uploads/

volumes:
  uploads-data:

Which you can run with docker-compose;

docker-compose up -d
Creating network "foo_default" with the default driver
Creating volume "foo_uploads-data" with default driver
Creating foo_db_1

基本上，它在docker compose版本3中不可用:

There's a couple of reasons volumes_from is not ported to the compose-file "3";

• In a swarm, there is no guarantee that the "from" container is running on the same node. Using volumes_from would not lead to the expected result.
  This is especially the case with bind-mounts, which, in a swarm, have to exist on the host (are not automatically created)
• There is still a "race" condition (as described earlier)
• The "data" container has to use exactly the right paths for volumes as the "app" container that uses the volumes (i.e. if the "app" uses the volume in /some/path/in/container, then the data container also has to have the volume at /some/path/in/container). There are many cases where the volume may be shared by multiple services, and those may be consuming the volume in different paths.

而且，如issue 19990中所述:

The "regular" volume you're describing is a bind-mount, not a volume; you specify a path from the host, and it's mounted in the container. No data is copied from the container to that path, because the files from the host are used.

For a volume, you're asking docker to create a volume (persistent storage) to store data, and copy the data from the container to that volume.

Volumes are managed by docker (or through a plugin) and the storage path (or mechanism) is an implementation detail, as all you're asking is a storage, that's managed.

对于您的问题，您需要定义一个Docker卷容器并在其中复制主机内容:

services:
  data:
    image: "nginx:alpine"
    volumes:
      - ./pg_hba.conf/:/var/lib/postgresql/data/pg_hba.conf