NAME

bootc-container-split-kernel-and-rootfs - Split kernel and rootfs from a container image

SYNOPSIS

bootc container split-kernel-and-rootfs

DESCRIPTION

Split kernel and rootfs from a container image

OPTIONS

--rootfs=ROOTFS

Operate on the provided rootfs

Default: /

--output=OUTPUT

Output directory for the extracted kernel files

EXAMPLES

Extract kernel files from the current root filesystem to /kernel:

bootc container split-kernel-and-rootfs --output /kernel

This extracts the kernel and initramfs from the current root filesystem (/) and places them in /kernel/<kernel-version>/ with filenames vmlinuz and initramfs.img. Files that belong to the kernel binary are moved along with it under the same names, when present. Currently that is only the FIPS HMAC file (.vmlinuz.hmac) shipped by Fedora and RHEL derivatives. Other files in /usr/lib/modules/<kernel-version>/, such as config or System.map, stay in the rootfs.

Extract kernel files from a mounted container rootfs:

bootc container split-kernel-and-rootfs --rootfs /mnt/container-rootfs --output /output/kernels

This extracts kernel files from a container filesystem mounted at /mnt/container-rootfs and places them in the output directory.

Example output structure:

After running the command, the output directory will contain:

/output/kernels/
└── 6.5.0-15-generic/
    ├── .vmlinuz.hmac (Fedora/RHEL, if present)
    ├── vmlinuz
    └── initramfs.img

where 6.5.0-15-generic is the detected kernel version from the source rootfs.

SEE ALSO

bootc(8)

VERSION

The Linux Foundation® (TLF) has registered trademarks and uses trademarks. For a list of TLF trademarks, see Trademark Usage.