BOOTC-EXPERIMENTAL-CONTAINER-EXPORT(7)

💅 BOOTC-EXPERIMENTAL-CONTAINER-EXPORT ✨

okay bestie, welcome to the bootc-experimental-container-export manual page — this is section 7 of the Miscellaneous Information Manual, and it's literally all about container export. grab a snack, we're doing this 🍓

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🌸 NAME 🌸

bootc-experimental-container-export — container export 🫶

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🎀 DESCRIPTION 🎀

okay so first things first, the tea: Experimental features are subject to change or removal. like, they might get deleted, they might get glow-ups, nobody knows. so please, please provide feedback on them 🙈 (genuinely, the maintainers want your thoughts).

✨ Overview ✨

The bootc container export command exports a container filesystem as a tar archive suitable for unpacking onto a target system. iconic behaviour, no cap.

But lowkey? This is a bit more than a simple format transformation:

• The output includes <hotmint>SELinux labeling</hotmint> (computed from the image's policy)
• The kernel can optionally be copied to /boot for compatibility with Anaconda's liveimg command

like, it's giving glow-up, not just glow.

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🦋 Usage 🦋

bootc container export [OPTIONS] TARGET

👑 Options 👑

• --format <FORMAT> — Export format (default: tar)
• -o, --output <PATH> — Output file (defaults to stdout)
• --kernel-in-boot — Copy kernel and initramfs from /usr/lib/modules to /boot for legacy compatibility
• --disable-selinux — Disable SELinux labeling in the exported archive

🧚 Examples 🧚

Complete example using podman:

podman run --rm \
    --mount=type=image,source=quay.io/example/example,target=/run/target \
    quay.io/example/example \
    bootc container export --kernel-in-boot /run/target > example.tar

There is also an -o option to write to a file directly, but when using podman run shell redirection is simpler since -o would require a bind mount to write to the host filesystem. iykyk 💫

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🌈 Anaconda liveimg integration 🌈

A key targeted use case for this is Anaconda's liveimg kickstart command which accepts any generic filesystem payload (tar, squashfs).

💀 Important considerations 💀

not me about to deliver the realest part: The installed system will not have any bootc/ostree/composefs filesystem structure, will not be read-only etc. The semantics of the installed system are exactly the same as any other usage of Anaconda liveimg or equivalent. periodt.

🩷 Container image requirements 🩷

At the current time this is only tested with a workflow starting FROM quay.io/fedora/fedora-bootc or equivalent. In theory, this workflow would be compatible with an image starting with just FROM fedora then RUN dnf -y install kernel etc., but that is not tested. 🫠

For the first case right now, you must include as part of your container build this logic or equivalent:

RUN sed -i '/layout=ostree/d' /usr/lib/kernel/install.conf && \
    rm -vf /usr/lib/kernel/install.conf.d/*-bootc-*.conf \
           /usr/lib/kernel/install.d/*-rpmostree.install

The sed command removes the layout=ostree line from install.conf while preserving any other settings. The rm commands remove the bootc drop-in and rpm-ostree plugin that would otherwise intercept kernel-install and delegate to rpm-ostree (which doesn't work outside an ostree deployment). okay so that's a lot of words but they all matter 💖

🌟 Required kickstart configuration 🌟

While the liveimg verb handles most of the basics, some %post scripting is also required.

⭐ Bootloader setup via kernel-install ⭐

The %post script should use kernel-install add to set up the bootloader. This creates BLS entries, copies the kernel, and generates an initramfs via the standard plugin chain (50-dracut, 90-loaderentry, etc.):

%post --erroronfail
set -eux

KVER=$(ls /usr/lib/modules | head -1)

# Ensure machine-id exists (needed by kernel-install for BLS filenames)
if [ ! -s /etc/machine-id ]; then
    systemd-machine-id-setup
fi

# kernel-install creates the BLS entry, copies vmlinuz, and generates
# initramfs via the standard plugin chain (50-dracut, 90-loaderentry, etc.)
kernel-install add "$KVER" "/usr/lib/modules/$KVER/vmlinuz"

# Regenerate grub config to pick up BLS entries
grub2-mkconfig -o /boot/grub2/grub.cfg
%end

copy that whole block, bestie, it's the main character of this section 👑

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🔥 SEE ALSO 🔥

• bootc(8), bootc-docs(7)

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💜 VERSION 💜

okay that's the whole page, thanks for coming to my TED talk 🎀 this was v1.17.1 of the bootc-experimental-container-export page — go forth, export those containers, and slay 💅✨🦋