使用 docker stack 进行卷挂载

Question

Following is my docker-stack file.

version: "3"
services:
  my-app:    
    image: my-image:latest    
    volumes:
      - ./certs:/certs   
    ports:
      - 6401:6401
    networks:
      my-net:        
         ipv4_address: 192.168.0.4
networks:
  my-net:
    external: true

It works fine on my machine, binding certs folder to certs inside the container. However doesn't work in my CI pipeline where i am deploying this service inside a docker-stack-node image. The error i get is

invalid mount config for type "bind": bind mount source path does not exist.

I read that If you bind mount a host path into your service's containers, the path must exist on every swarm node. So, I think i need to create a named volume. However, with the named volume i can't specify source path of certs. It's confusing. Can someone help with this?

Answer 1

@Niraj I have ran into this issue as well and have figured out that each node needs the files to run. In your case I would do this:

1. In your Dockerfile create the certs folder
   • RUN mkdir /certs
2. Change compose-file to use absolute path
   • - $PWD/certs:/certs
3. Copy certs into container
   • docker cp <file_name> <container_id>:/certs

Hope this helps!

Answer 2

To bind to a directory the directory has to exist on the host machine so ./certs doesn't exist on the host running the container so...

If you want to bind the volume you will need to run:

mkdir -p ./certs

on the machine running the container and it will work.

It works on your machine because the directory exists locally.

Copy directory to host

scp -r /local/directory/ username@to_host:/remote/directory/