febootstrap-supermin-helper(8)

1FEBOOTSTRAP-SUPERMIN-HELPER(8V)irtualization SupporFtEBOOTSTRAP-SUPERMIN-HELPER(8)
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NAME

6       febootstrap-supermin-helper - Reconstruct initramfs from supermin
7       appliance.
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SYNOPSIS

10        febootstrap-supermin-helper supermin.img hostfiles.txt host_cpu kernel initrd
11        febootstrap-supermin-helper input [...] host_cpu kernel initrd
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13        febootstrap-supermin-helper -f ext2 input [...] host_cpu kernel initrd appliance
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15        febootstrap-supermin-helper -f checksum input [...] host_cpu
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DESCRIPTION

18       febootstrap-supermin-helper reconstructs a bootable kernel and
19       initramfs from a supermin appliance.  First you should be familiar with
20       febootstrap(8).
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PARAMETERS

23       Of the required parameters, the first few are input files, and the last
24       two or three are output files.
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26       "supermin.img" and "hostfiles.txt" are the input files which describe
27       the supermin appliance.  (You can also use a directory name here which
28       is searched for files).
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30       "host_cpu" should be the host CPU, eg. "x86_64" or "i686".
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32       "kernel", "initrd" and "appliance" are the temporary output files that
33       this script produces.  These output files are meant to be used just for
34       booting the appliance, and should be deleted straight afterwards.  The
35       extra "appliance" parameter is only required when the format is "ext2".
36       None of these parameters are needed for the checksum output "-f
37       checksum".
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OPTIONS

40       -f fmt | --format fmt
41           Select the output format for the appliance.  Possible formats are:
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43           cpio
44               A Linux initramfs.  This is the default.
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46               In this case you have to supply names for the "kernel" and
47               "initrd", where the "initrd" is the appliance.
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49           ext2
50               An ext2 filesystem.
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52               In this case you have to supply names for the "kernel", a small
53               "initrd" which is used just to locate the appliance, and the
54               "appliance" (the ext2 filesystem).
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56           checksum
57               Output a checksum.
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59               This prints a checksum which only changes when one of the input
60               files changes.
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62               You can use this in order to cache the output of a previous run
63               of this program: computing the checksum is much quicker than
64               building an appliance, and you only need to invalidate the
65               cache (and consequently rebuild the appliance) when the
66               checksum changes.  Note that the host_cpu and the UID of the
67               current user are included in the checksum.
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69       -k file | --kmods file
70           If this option is specified, then "file" should be a list of
71           wildcards matching kernel module names, eg:
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73            virtio*.ko
74            scsi*.ko
75            piix.ko
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77           In this case, only kernel modules matching those wildcards will be
78           included in the output appliance.  Note: You must resolve any
79           dependencies yourself as this does not pull in dependent modules
80           automatically.
81
82           If this option is not specified, then every kernel module from the
83           host will be included.  This is safer, but can produce rather large
84           appliances which need a lot more memory to boot.
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86       -u user | --user user | -g group | --group group
87           Run febootstrap-supermin-helper as an alternate user and/or group.
88           "user" and "group" can be specified as either a name, which will be
89           resolved using the system name service, or a uid/gid.  Use of these
90           options requires root privileges.
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92           Use of these options is required if running febootstrap-supermin-
93           helper as root with the effective uid/gid set to non-root.  Bash
94           will reset the effective uid/gid to the real uid/gid when invoked.
95           As febootstrap-supermin-helper uses bash in parts, this will result
96           in the creation of an appliance with a mixture of ownerships.
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SPEED

99       In libguestfs, on a mid-range Intel-based PC, we reconstruct the
100       initramfs using this script in around 1/5th of a second (assuming a
101       "hot cache" - it's rather slower when run the first time on a cold
102       cache).
103
104       Some tips to improve performance:
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106       ·   Use a kernel module whitelist (the "--kmods" option), and only list
107           the kernel modules you really need.
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109       ·   Minimize the appliance, removing as much extraneous junk as
110           possible.
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AUTHORS

116       Richard W.M. Jones <rjones @ redhat . com>
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COPYRIGHT

119       (C) Copyright 2009-2010 Red Hat Inc.,
120       <http://people.redhat.com/~rjones/febootstrap>.
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122       This program is free software; you can redistribute it and/or modify it
123       under the terms of the GNU General Public License as published by the
124       Free Software Foundation; either version 2 of the License, or (at your
125       option) any later version.
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127       This program is distributed in the hope that it will be useful, but
128       WITHOUT ANY WARRANTY; without even the implied warranty of
129       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
130       General Public License for more details.
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132       You should have received a copy of the GNU General Public License along
133       with this program; if not, write to the Free Software Foundation, Inc.,
134       675 Mass Ave, Cambridge, MA 02139, USA.
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138febootstrap-3.1                   2010-12-07    FEBOOTSTRAP-SUPERMIN-HELPER(8)