挂载后Docker卷为空

Question

我尝试为我的应用程序设置一个Docker-compose，其中包括基于nginx映像的服务。我想有可能仅从我的主机访问配置。但是当我用

挂载卷时

    volumes:
      - ./nginxConf:/etc/nginx

该卷为空，容器崩溃。

完整的docker-compose.yml

version: '3'
services: 
  frontend:
    image: myFrontend
    restart: always
    environment: 
      - API_URL=http://localhost:3000/api/v1
    ports:
      - "80:80"
      - "443:443"
    depends_on:
      - "api"
    volumes:
      - ./nginxConf:/etc/nginx
  api:
    image: myApi
    restart: always
    command: bash -c "npm run build && npm run start"
    ports: 
      - "3000:3000"
    links: 
      - mongo
    depends_on: 
      - mongo
  mongo:
    container_name: mongo
    image: mongo
    ports:
      - "27017:27017"