Section: Virtualization Support (8)Updated: 2010-05-14Local indexUp
febootstrap-to-initramfs - Convert febootstrap root to initramfs (cpio) file.
febootstrap-to-initramfs [--files=filelist] DIR > initrd.img
febootstrap-to-initramfs converts the filesystem created by
febootstrap(8) into an initramfs image. This allows the new system
to be booted on real hardware or inside a QEMU-based virtual machine.
An initramfs image is just a compressed cpio file, so you could
uncompress it with gunzip(1) and use cpio(1) to convert it into
The permissions inside the initrd image are corrected automatically
(see the discussion of fakeroot logfile in the febootstrap(8)
page). You do not need to run this command as root.
"filelist" should be a file containing a list of the files to be
added to the initramfs (one per line). Only those files are added and
any others are ignored.
When the "--files" option is not given, all files in "DIR" are added
to the initramfs image.
This prevents the initramfs image from being compressed.
Linux can boot from uncompressed initramfs images (in fact, faster),
but they take up a lot more space on disk.
Normal initramfs images start by executing the program or script
called "/init". febootstrap does not create this script, so you may
wish to, particularly for very minimal bootstraps that don't have the
normal SysVinit/upstart machinery. It's also required if the kernel
cannot find a ``real'' root filesystem (the root filesystem that we
built and placed in an initramfs doesn't count).
Linux will try to run the following commands in turn, unless you
override it using the "init=cmd" kernel option:
Initramfs images are uncompressed by the kernel into memory. When
booting the new system you will need at least enough free RAM to store
the uncompressed filesystem plus extra to run any programs. Bear
this in mind when creating very large filesystems.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.