febootstrap-supermin-helper - Reconstruct initramfs from supermin
febootstrap-supermin-helper supermin.img hostfiles.txt host_cpu kernel initrd
febootstrap-supermin-helper input [...] host_cpu kernel initrd
febootstrap-supermin-helper reconstructs a bootable kernel and
initramfs from a supermin appliance. First you should be familiar with
febootstrap(8), febootstrap-to-initramfs(8) and
Of the four or five required parameters, the first few are input files,
and the last two are output files.
"supermin.img" and "hostfiles.txt" are the input files which describe
the supermin appliance. (You can also use a directory name here which
is searched for files).
"host_cpu" should be the host CPU, eg. "x86_64" or "i686".
"kernel" and "initrd" are the temporary output files that this script
produces. These output files are meant to be used just for booting the
appliance, and should be deleted straight afterwards.
-k file | --kmods file
If this option is specified, then "file" should be a list of
wildcards matching kernel module names, eg:
In this case, only kernel modules matching those wildcards will be
included in the output appliance. Note: You must resolve any
dependencies yourself as this does not pull in dependent modules
If this option is not specified, then every kernel module from the
host will be included. This is safer, but can produce rather large
appliances which need a lot more memory to boot.
In libguestfs, on a mid-range Intel-based PC, we reconstruct the
initramfs using this script in around 1/5th of a second (assuming a
"hot cache" - it’s rather slower when run the first time on a cold
Some tips to improve performance:
· Use a kernel module whitelist (the "--kmods" option), and only list
the kernel modules you really need.
· Minimize the appliance, removing as much extraneous junk as
As well as using febootstrap-minimize(8) it is worth checking for
anything that is not necessary for your particular application and
removing it by hand.
Richard W.M. Jones <rjones @ redhat . com>
(C) Copyright 2009-2010 Red Hat Inc.,
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.