Mount an empty folder in host to a non-empty folder in Docker

Question

The tool I'm using is delivered in a Docker image. Since installing the tool is extremely complicated with a bunch of dependencies, I want to work on the host with my IDE, but run it on the container.

So after download and load the image, I run:

sudo docker run -it -v /home/myself/WIP/thetool:/home/thetool name/label

Without mounting, the tool is located under /home/thetool, but with mounting, this folder is empty (since the folder in the host is empty).

Do I need to copy the tool from the container, then mount it, or there is a way to do it directly.

Answer 1

You can actually make that work with a docker volume with explicit device mount point.

If the directory /home/myself/WIP/thetool is empty, do the following:

Create a docker volume as such:

---

docker volume create --driver local \
    --opt type=none \
    --opt device=/home/myself/WIP/thetool \
    --opt o=bind \
    tool_vol

---

Start the container and mount the created volume:

sudo docker run -it -v tool_vol:/home/thetool name/label

Now the data that is in /home/thetool inside the container will be available inside /home/myself/WIP/thetool even though the host folder was initially empty.