Mount "named volume" as non-root in Docker

The named volume initializes to the contents of your image at that location, so you need to set the permissions inside your Dockerfile:

$ cat df.vf-uidFROM busyboxRUN mkdir -p /data && echo "hello world" > /data/hello && chown -R 1000 /data$ docker build -t test-vf -f df.vf-uid .Sending build context to Docker daemon 23.06 MBStep 1 : FROM busybox ---> 2b8fd9751c4cStep 2 : RUN mkdir -p /data && echo "hello world" > /data/hello && chown -R 1000 /data ---> Using cache ---> 41390b132940Successfully built 41390b132940$ docker run -v test-vol:/data --rm -it test-vf ls -alR /data/data:total 12drwxr-xr-x    2 1000     root          4096 Sep 19 15:26 .drwxr-xr-x   19 root     root          4096 Sep 19 15:26 ..-rw-r--r--    1 1000     root            12 Aug 22 11:43 hello

If you use the new --mount syntax instead of the old -v/--volume syntax it is supposedly possible to assign a uid to the volume's contents via docker volume create somename --opt -o=uid=1000 or something similar.

See https://docs.docker.com/engine/reference/commandline/volume_create/#driver-specific-options

I haven't fully tested this to run as non-root or using the dockremap dynamic user with the userns-map option but hope to soon.