github.com/containers/podman/v2@v2.2.2-0.20210501105131-c1e07d070c4c/test/build/preserve-volumes/Dockerfile (about)

     1  FROM alpine
     2  RUN mkdir -p /vol/subvol/subsubvol
     3  RUN dd if=/dev/zero bs=512 count=1 of=/vol/subvol/subsubvol/subsubvolfile
     4  VOLUME /vol/subvol
     5  # At this point, the contents below /vol/subvol should be frozen.
     6  RUN dd if=/dev/zero bs=512 count=1 of=/vol/subvol/subvolfile
     7  # In particular, /vol/subvol/subvolfile should be wiped out.
     8  RUN dd if=/dev/zero bs=512 count=1 of=/vol/volfile
     9  # However, /vol/volfile should exist.
    10  VOLUME /vol
    11  # And this should be redundant.
    12  VOLUME /vol/subvol
    13  # And now we've frozen /vol.
    14  RUN dd if=/dev/zero bs=512 count=1 of=/vol/anothervolfile
    15  # Which means that in the image we're about to commit, /vol/anothervolfile
    16  # shouldn't exist, either.
    17  
    18  # ADD files which should persist.
    19  ADD Dockerfile /vol/Dockerfile
    20  RUN stat /vol/Dockerfile
    21  ADD Dockerfile /vol/Dockerfile2
    22  RUN stat /vol/Dockerfile2