NAME

bootc-destructive-cleanup.service

DESCRIPTION
This systemd service runs on first boot after an "alongside" installation using bootc install to-existing-root --cleanup. Its purpose is to clean up files from the previous operating system.

The service runs as a oneshot unit and executes a distribution-specific cleanup script located at /usr/lib/bootc/fedora-bootc-destructive-cleanup (for Fedora derivatives).

How it works

1.  During bootc install to-existing-root --cleanup, a stamp file is created at /sysroot/etc/bootc-destructive-cleanup

2.  A systemd generator (bootc-systemd-generator) detects this stamp file at boot time and enables the bootc-destructive-cleanup.service unit

3.  The service runs the cleanup script on first boot

What the cleanup script does
On Fedora derivatives, the cleanup script performs the following actions:

•   Remounts /sysroot as read-write

•   Removes all RPM packages installed in the physical root (the previous OS)

•   Removes all container images from /sysroot/var/lib/containers using podman system prune --all -f

Note: The cleanup script does not remove stopped containers, so some storage may remain. This behavior may change in the future.

CUSTOMIZING THE CLEANUP SCRIPT
The current implementation ships a Fedora-specific cleanup script. Other distributions can provide their own cleanup script by creating an executable at /usr/lib/bootc/fedora-bootc-destructive-cleanup or by modifying the systemd unit file to reference a different path.

For an example implementation, see the Fedora cleanup script ⟨https://github.com/bootc-dev/bootc/blob/main/contrib/scripts/fedora-bootc-destructive-cleanup⟩.

PREVIOUS FILESYSTEM DATA
After an alongside installation, the previous root filesystem data is accessible at /sysroot (the "physical root"). Previous mount points or subvolumes will not be automatically mounted in the new system; for example, a btrfs subvolume for /home will not be automatically mounted to /sysroot/home. These filesystems persist and can be handled manually or defined as mount points in the bootc image.

SEE ALSO
bootc(8), bootc-install-to-existing-root(8), system-reinstall-bootc(8)

VERSION
v1.15.2