tmpfs error when building void iso in docker container

[wbehrens-on-gh]

I'm trying to build a custom void .iso in a docker container to test since the system I'm on currently isn't running void. I've included the commands & dockerfile I've been using to try and build as well as the error
error

[7/9] Generating GRUB support for EFI systems...
umount: /root/tmp.cyQs8TRvyC: not mounted.
[8/9] Cleaning up rootfs...
[9/9] Generating squashfs image (xz) from rootfs...
mount: /mklive/tmp.fncIhavHpt/tmp-rootfs: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error.
umount: /mklive/tmp.fncIhavHpt/tmp-rootfs: not mounted.
/mklive/tmp.fncIhavHpt/void-host/usr/bin/mksquashfs: error while loading shared libraries: liblzo2.so.2: cannot open shared object file: No such file or directory
ERROR: Failed to generate squashfs image
make: *** [Makefile:22: build] Error 1

build_iso.sh

#!/bin/sh

set -eu

. /config/packages

cd /mklive || exit 1

echo "./mklive.sh \"$REPO\" -a \"$ARCH\" -p \"$PKGS\" -S \"$SERVICES\" -T \"$NAME\" -o \"/output/$ISO\""

./mklive.sh "$REPO" \
    -a "$ARCH" \
    -p "$PKGS" \
    -S "$SERVICES" \
    -T "$NAME" \
    -o "/output/$ISO" 

Dockerfile

FROM voidlinux/voidlinux

ARG repo=https://repo-default.voidlinux.org/

ENV VERSION=0
ENV ARCH=x86_64
ENV NAME=willows
ENV REPO=${repo}
ENV ISO=${NAME}-${VERSION}-${ARCH}.iso

# mklive must be run as root
USER root

# Install required packages
RUN xbps-install -Syu \
        xbps \
        git \
        kmod \
        make \
        bash \
        liblz4 \
        qemu-user-static

# Clone and build mklive
RUN git clone https://github.com/void-linux/void-mklive /mklive \
    && make -C /mklive

# Create volumes to transfer information
RUN mkdir -p /output /config
VOLUME [ "/output" ]
VOLUME [ "/config" ]

# Run the build script
COPY scripts/build_iso.sh /usr/bin/build_iso
RUN chmod +x /usr/bin/build_iso
CMD [ "build_iso" ]

docker run: docker run --privileged --cap-add=SYS_ADMIN -v ${OUTDIR}:/output -v ${CONFIG}:/config -e NAME=${NAME} -e ARCH=${ARCH} -e VERSION=${VERSION} ${NAME}:${TAG}

[classabbyamp]

one of the errors is caused by a missing dependency: squashfs-tools

however, I'm not sure this will work at all, based on the other error messages. I added squashfs-tools and tried your dockerfile/script myself, and the image generated is 5 times smaller than it should be and does not contain a proper efi partition.

My guess as to what's happening is it's not able to mount and unmount things from inside the container:

[7/9] Generating GRUB support for EFI systems...
umount: /root/tmp.nZsHeKVuRp: not mounted.
[8/9] Cleaning up rootfs...
[9/9] Generating squashfs image (xz) from rootfs...
mount: /mklive/tmp.oNBnYLJ9hV/tmp-rootfs: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error.
       dmesg(1) may have more information after failed mount system call.
umount: /mklive/tmp.oNBnYLJ9hV/tmp-rootfs: not mounted.

[classabbyamp]

also, the images from dockerhub are old and no longer supported, use ghcr.io/void-linux/void-linux:latest-full-x86_64

[wbehrens-on-gh]

one of the errors is caused by a missing dependency: squashfs-tools

however, I'm not sure this will work at all, based on the other error messages. I added squashfs-tools and tried your dockerfile/script myself, and the image generated is 5 times smaller than it should be and does not contain a proper efi partition.

My guess as to what's happening is it's not able to mount and unmount things from inside the container:

[7/9] Generating GRUB support for EFI systems...
umount: /root/tmp.nZsHeKVuRp: not mounted.
[8/9] Cleaning up rootfs...
[9/9] Generating squashfs image (xz) from rootfs...
mount: /mklive/tmp.oNBnYLJ9hV/tmp-rootfs: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error.
       dmesg(1) may have more information after failed mount system call.
umount: /mklive/tmp.oNBnYLJ9hV/tmp-rootfs: not mounted.

Do you have any more insight on this? like what specifically is being mounted since searching for mounting issues in docker just returns results about the VOLUME function.

[classabbyamp]

no clue, sorry

[classabbyamp]

so, I was able to get this to work in Github CI in a void docker container, using the following:

...
    container:
      image: 'ghcr.io/void-linux/void-linux:20230204RC01-full-x86_64'
      options: --privileged
      volumes:
        - /dev:/dev
      env:
        PATH: '/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/sbin:/usr/local/bin:/tmp/bin'
        REPO: "${{ inputs.mirror }}"

    steps:
      - name: Prepare container
        shell: sh
        run: |
          # Switch to repo-ci mirror
          mkdir -p /etc/xbps.d && cp /usr/share/xbps.d/*-repository-*.conf /etc/xbps.d/
          sed -i 's|https://repo-default.voidlinux.org/current|'"$REPO"'|g' /etc/xbps.d/*-repository-*.conf
          # Sync and upgrade once, assume error comes from xbps update
          xbps-install -Syu || xbps-install -yu xbps
          # Upgrade again (in case there was a xbps update)
          xbps-install -yu
          # Install depedencies
          xbps-install -yu bash make git kmod xz lzo qemu-user-static outils dosfstools e2fsprogs
...

(it then goes on to clone the repo and build things, see #331)

the important parts are:

• it uses a current void docker image
• it passes --privileged to docker run
• it mounts /dev in the container, so loopback devices can work (they get mounted properly and the kernel tree can see them, but the filesystem nodes are not added without this)

DISCLAIMER: I have no clue what this will do on a machine that isn't some throwaway CI VM, so be careful.