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misc:create-chroot [2008/12/31 07:56] – old revision restored siretartmisc:create-chroot [2009/01/05 22:06] (current) – old revision restored siretart
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 +<code perl>
 +#!/usr/bin/perl
  
 +use Getopt::Std;
 +use strict;
 +use Term::Prompt;
 +use File::Copy;
 +
 +my %OPTS;
 +
 +if ( !getopts("hfL", \%OPTS) or $OPTS{h}) {
 +    pod2usage(2);
 +}
 +
 +die "Must run as root, sorry\n" if ($>) != 0;
 +
 +my $LVS;
 +my $LV = @ARGV[0];
 +my $VG = $OPTS{g};
 +
 +my %MIRRORS = (
 +     gutsy => "http://archive.ubuntu.com/ubuntu",
 +     sid => "http://ftp.debian.org",
 +    );
 +
 +
 +print "using mirror $MIRRORS{$LV} for $LV" if $MIRRORS{$LV} or die "unknown distro";
 +
 +my $mountpoint = "/mnt";
 +
 +if ( ! $VG ) {
 +    my $i = 0;
 +    open(my $VGS, "/sbin/lvm vgs|");
 +    <$VGS>; # skip first line
 +    while (<$VGS>) {
 + $i = $i + 1;
 + m/\s+(\S+)\s+/;
 + $VG = $1;
 +    }
 +    die "please specify your VG via -g" if ($i != 1);
 +}
 +
 +print "using volume group $VG\n";
 +my $device = "/dev/$VG/$LV";
 +
 +# check for filesystem mounted...
 +open (my $MOUNTS, "/proc/mounts");
 +while (<$MOUNTS>) {
 +    # example output:
 +    #/dev/mapper/hermes--vg-gutsy on /mnt type ext3 (rw)
 +    if (m/^(\S+) (\S+)/) {
 +
 + die "volumegroup ($1) already mounted" if ("$1" eq "$device");
 + die "$mountpoint ($2) is already mounted" if ($2 eq "$mountpoint");
 +    }
 +}
 +
 +print "Looking for $LV\n";
 +open ($LVS, "/sbin/lvm lvs|");
 +<$LVS>; # skip first line
 +while (<$LVS>) {
 +    if (m/\s+($LV)\s+(\S+)/) {
 + my $VG = $2;
 + my $remove = undef;
 + if (! $OPTS{f}) {
 +     $remove = prompt ("y", "Logical Volume $LV bfound on this system, remove?", undef, "y");
 + } else {
 +     $remove = 1;
 + }
 + if ($remove) {
 +     print "removing $device\n";
 +     system ("lvm", "lvremove", "-f", "$device") == 0
 +     or die "could not remove $device: $?";
 + }
 + last;
 +    }
 +}
 +
 +my $size = $OPTS{L};
 +if ( ! $size ) {
 +    $size = "3G";
 +}
 +
 +print "creating $device with a size of $size\n";
 +system("/sbin/lvm", "lvcreate", "-L", "$size", "-n", "$LV", "$VG") == 0
 + or die "could not create $LV: $?";
 +system("/sbin/mkfs", "-t", "ext3", "$device") == 0
 + or die "failed to create filesystem: $?";
 +system("/bin/mount", "$device", "$mountpoint") == 0
 + or die "failed to mount filesystem $device on $mountpoint: $?";
 +
 +if (system("/usr/sbin/debootstrap", "$LV", $mountpoint, $MIRRORS{$LV}) != 0) {
 +    system("/bin/umount", "$mountpoint");
 +    die "failed to bootstrap system";
 +}
 +
 +copy("/etc/hosts", "$mountpoint/etc");
 +copy("/etc/sudoers", "$mountpoint/etc");
 +
 +system("/bin/umount", "$mountpoint") == 0
 + or die "failed to umount filesystem: $?";
 +
 +=head1 NAME
 +
 +  create-chroot
 +
 +=head1 SYNOPSIS
 +
 +  create-chroot [-g VG] [-f] [-L size] distname
 +
 + -g  name of Volume group if several on this system
 + -f force removal of existing volume group
 + -L size of the logical volume. defaults to 3GB.
 +
 + distname name of the distribution you want to bootstrap
 +
 +=head1 DESCRIPTION
 +
 +B<create-chroot> is a small shell script for creating LVM based chroot
 +ready for use with schroot. If the distribution already exists, the
 +existing logical volume will be removed. It checks if a volumegroup
 +named like the dist you want to install is already on the system. If
 +there isn't, then it will create a logical volume, make a filesystem and
 +bootstrap the selected system on it. It then copies the files
 +C</etc/hosts> and C</etc/sudoers> into it.
 +
 +After setting it up, make sure you have the chroot added correctly to
 +C</etc/schroot/schroot.conf>.
 +
 +=head1 AUTHOR
 +
 +Reinhard Tartler <siretart@ubuntu.com>
 +
 +</code>