Dear Stephen, Follow ups of https://lists.gnu.org/archive/html/help-guix/2020-05/msg00249.html and bug#41607 CC http://issues.guix.gnu.org/41607
On Sat, 30 May 2020 at 19:02, Stephen Scheck <singularsyn...@gmail.com> wrote: > You can convince yourself of this by doing something like the following: > > docker run <some-linux-image> > docker exec <container-id> dd if=/dev/urandom of=/RANDOM-DATA > bs=1048576 count=1024 > docker commit <container-id> > docker exec <container-id> rm /RANDOM-DATA > docker commit <container-id> It does not convince myself and maybe I am doing wrongly but it is not what I am observing for an example with more than 2 'commits'. Here my session, based on your images rename "fresh" because it will happen on any image. --8<---------------cut here---------------start------------->8--- $ docker images REPOSITORY TAG IMAGE ID CREATED SIZE fresh latest c36cef8306d5 3 weeks ago 1.06GB singularsyntax/guix-bootstrap 1.1.0-alpine-3.11 c36cef8306d5 3 weeks ago 1.06GB $ CONTAINER=`docker run --detach --tty --privileged fresh` $ docker exec --interactive --tty $CONTAINER /bin/sh / # dd if=/dev/urandom of=/DATA bs=1234567 count=1024 dd if=/dev/urandom of=/DATA bs=1234567 count=1024 1024+0 records in 1024+0 records out / # exit exit $ HASH=`docker commit $CONTAINER` && docker tag $HASH add-data $ docker stop $CONTAINER && docker rm $CONTAINER cb89992b76ace2afe5dc6e082c8de121c483dfeeb688d89849713e2cf90b68c7 cb89992b76ace2afe5dc6e082c8de121c483dfeeb688d89849713e2cf90b68c7 $ CONTAINER=`docker run --detach --tty --privileged add-data` $ docker exec --interactive --tty $CONTAINER /bin/sh / # rm /DATA rm /DATA / # dd if=/dev/urandom of=/OTHER bs=1234567 count=1024 dd if=/dev/urandom of=/OTHER bs=1234567 count=1024 1024+0 records in 1024+0 records out / # exit exit $ HASH=`docker commit $CONTAINER` && docker tag $HASH rm-data-add-other $ docker stop $CONTAINER && docker rm $CONTAINER 93e9afe593226ec29669efe8515b47487f455d4ad5e012cc67372c2549ec7256 93e9afe593226ec29669efe8515b47487f455d4ad5e012cc67372c2549ec7256 $ CONTAINER=`docker run --detach --tty --privileged rm-data-add-other` $ docker exec --interactive --tty $CONTAINER /bin/sh / # rm /OTHER rm /OTHER / # exit exit $ HASH=`docker commit $CONTAINER` && docker tag $HASH rm-other $ docker stop $CONTAINER && docker rm $CONTAINER 469b341c2f394ef05f5f43a5d96239853e3552d979028a457a9bdd1096a8fab4 469b341c2f394ef05f5f43a5d96239853e3552d979028a457a9bdd1096a8fab4 $ docker images REPOSITORY TAG IMAGE ID CREATED SIZE rm-other latest b80d300aa755 23 seconds ago 3.59GB rm-data-add-other latest de551eac1d55 About a minute ago 3.59GB add-data latest 6a563daccccd 3 minutes ago 2.32GB fresh latest c36cef8306d5 3 weeks ago 1.06GB singularsyntax/guix-bootstrap 1.1.0-alpine-3.11 c36cef8306d5 3 weeks ago 1.06GB $ CONTAINER=`docker run --detach --tty --privileged rm-other` $ docker exec --interactive --tty $CONTAINER /bin/sh / # ls / ls / bin dev etc gnu home lib media mnt opt proc root run sbin srv sys tmp usr var / # exit exit --8<---------------cut here---------------end--------------->8--- > You'll end up with two new images - the first one should be about 1 GB > larger than the base image, > the second one the same size. As you see, the image 'rm-other' does not container either /DATA or /OTHER and its size is not the same than the initial one 'fresh'. So I do not know if the correct Docker terminology is "layer" because the issue is definitely on the Docker side and not on the Guix side. Cheers, simon
