GNU bug report logs - #41607
Deleted store items are not actually deleted

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Package: guix;

Reported by: Leo Famulari <leo <at> famulari.name>

Date: Fri, 29 May 2020 19:10:02 UTC

Severity: normal

Done: Chris Marusich <cmmarusich <at> gmail.com>

Bug is archived. No further changes may be made.

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From: zimoun <zimon.toutoune <at> gmail.com>
To: Stephen Scheck <singularsyntax <at> gmail.com>, 41607 <at> debbugs.gnu.org
Cc: Chris Marusich <cmmarusich <at> gmail.com>, help-guix <help-guix <at> gnu.org>
Subject: bug#41607: Guix Docker image inflation
Date: Sun, 31 May 2020 10:24:25 +0200

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 <singularsyntax <at> 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
This bug report was last modified 5 years and 43 days ago.

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