build with volumes in the docker-compose.yml

I want to run multiple web application images with NGINX.

So I wrote docker-compose.yml which build nginx image and run nodejs containers.

I have SSL Certificate issued by letsencrypt.

The certificate files is located in /etc/letsencrypt/live/mydomain.com/

I want NGINX container to read the files.

So, I appended volumes: - /etc/letsencrypt/live/mydomain.com/:/etc/cert:ro to docker-compose.yml.

But nginx.conf cannot read the files.

I found that the directory /etc/cert doesn't exist and it's mounted as bind type.

I want to know how to set volumes in the docker-compose.yml file to read inside of containers.

docker-compose.yml

version: '2.0'

services:  
  nginx:
    container_name: manager
    build: ./nginx
    links:
      - app-1:app-1
      ...
    ports:
      - 80:80
      - 443:443
    volumes:
      - /etc/letsencrypt/live/mydomain.com/:/etc/cert:ro
    depends_on:
      - app-1
      ...

  app-1:
    container_name: audio-1
    image: audio:test
    ports:
      - 80

  ...

nginx.conf

worker_processes 4;

events { worker_connections 1024; }

http {  
  upstream node-app {
    least_conn;
    server app-1:80 weight=10 max_fails=3 fail_timeout=60s;
    ...
  }

  server {
    listen 80;
    return 301 https://$host$request_uri;
  }

  server {
    listen 443 ssl;
    ssl_certificate /etc/cert/fullchain.pem;
    ssl_certificate_key /etc/cert/privkey.pem;
    location / {
      proxy_pass http://node-app;
      ...
    }
  }
}

error

nginx: [emerg] BIO_new_file("/etc/cert/fullchain.pem") failed (SSL: error:02001002:system library:fopen:No such file or directory:fopen('/etc/cert/fullchain.pem','r') error:2006D080:BIO routines:BIO_new_file:no such file)

$docker inspect manager

...
"Mounts": [
  {
    "Type": "bind",
    "Source": "/etc/letsencrypt/live/luvber.kr",
    "Destination": "/etc/cert",
    "Mode": "ro",
    "RW": false,
    "Propagation": "rprivate"
   }
 ],
...

Thanks