Docker: environment variable in `VOLUME` instruction?

Question

Let say I have this variable: ENV MY_DATA="/my/dir/data"

And then use it as: VOLUME [$MY_DATA]

After building image and connecting to container, what I see is this:

If I add it as VOLUME ["/my/dir/data"], then such artifact directories do not appear. Is there some special syntax I need to use via VOLUME so it would render my ENV correctly?

Answer 1

Here's a quick Dockerfile for illustration:

FROM busybox
# ARG MY_DATA="/my/dir/data" <- Works too.
ENV MY_DATA="/my/dir/data"
VOLUME $MY_DATA
ENTRYPOINT ls -d /my/dir/data

Build the image and run it:

docker build -t <tag> .
docker run -t --rm <tag>
/my/dir/data        # list the volume created as expected
- or -
docker run -it --entrypoint "" --rm <tag> sh
ls -d /my/dir/data  # list the volume created as expected