Mounting a directory to docker container

Question

I am trying to mount a host directory to my nginx docker container. However, it's not mounting what I would expect.

docker-compose.yml:

nginx:
  image: nginx
  volumes:
    - ./app:/root/testfolder

Here's the contents of the directory in the container:

root@846e68e6e8b5:/# ls root/testfolder/
50x.html  index.html

And the directories on my host:

bash-3.2$ ls
app         bower.json      docker-compose.yml  gulpfile.js     node_modules        package.json
bash-3.2$ ls app/
app.js          assets      bower_components        common      index.html      modules
bash-3.2$ 

This is the current versions I am running:

OSX 10.10.5
Docker version 1.10.0, build 590d5108
docker-compose version 1.6.0, build d99cad6
docker-machine version 0.6.0, build e27fb87

I'd expect the host directory ./app to be mounted in root/testfolder. Why is this not the case?

Answer 1

If you are using Docker Machine on Mac or Windows, docker has limited access to your OS X or Windows filesystem. By default Docker Machine tries to auto-share your /Users (OS X) or C:\Users (Windows) directory.

So the folder /app must be located somewhere under /Users directory in the host.

All other paths come from your virtual machine’s filesystem, so if you want to make some other host folder available for sharing, you need to do additional work. In the case of VirtualBox you need to make the host folder available as a shared folder in VirtualBox.