lxc-clone-aufs

#!/bin/sh

#
# lxc: linux Container library

# Authors:
# Serge Hallyn <serge.hallyn@ubuntu.com>
# Daniel Lezcano <daniel.lezcano@free.fr>

# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.

# This library 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
# Lesser General Public License for more details.

# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

set -e

usage() {
    echo "usage: $(basename $0) -o ORIG_NAME -n NEW_NAME [-s] [-h] [-L FS_SIZE]" >&2
    echo "        [-v VG_NAME] [-p LV_PREFIX] [-t FS_TYPE]" >&2
}

help() {
    usage
    echo >&2
    echo "Clone an existing container on the system." >&2
    echo >&2
    echo "Options:" >&2
    echo "  -o ORIG_NAME   specify the name of the original container" >&2
    echo "  -n NEW_NAME    specify the name of the new container" >&2
    echo "  -s             make the new rootfs a snapshot of the original" >&2
    echo "  -L FS_SIZE     specify the new filesystem size (default: same as original)" >&2
    echo "  -v VG_NAME     specify the new LVM volume group name (default: lxc)" >&2
    echo "  -p LV_PREFIX   add a prefix to new LVM logical volume names" >&2
    echo "  -t FS_TYPE     specify the new filesystem type (default: ext3;" >&2
    echo "                  only works for non-snapshot LVM)" >&2
}

usage_err() {
    [ -n "$1" ] && echo "$1" >&2
    usage
    exit 1
}

optarg_check() {
    [ -n "$2" ] || usage_err "option $1 requires an argument"
}

. /usr/share/lxc/lxc.functions
snapshot=no
lxc_size=_unset
lxc_vg=lxc
lxc_lv_prefix=""
fstype=ext3

while [ $# -gt 0 ]; do
    opt="$1"
    shift
    case "$opt" in
        -h|--help)
            help
            exit 1
            ;;
        -s|--snapshot)
            snapshot=yes
            snapshot_opt="-s"
            ;;
        -o|--orig)
            optarg_check $opt $1
            lxc_orig=$1
            shift
            ;;
        -L|--fssize)
            optarg_check $opt $1
            lxc_size=$1
            shift
            ;;
        -t|--fstype)
            optarg_check $opt $1
            fstype=$1
            shift
            ;;
        -v|--vgname)
            optarg_check $opt $1
            lxc_vg=$1
            shift
            ;;
        -n|--name)
            optarg_check $opt $1
            lxc_new=$1
            shift
            ;;
        -p|--lvprefix)
            optarg_check $opt $1
            lxc_lv_prefix=$1
            shift
            ;;
        --)
            break
            ;;
        -?)
            usage_err "Unknown option: '$opt'"
            ;;
        -*)
            # split opts -abc into -a -b -c
            set -- $(echo "${opt#-}" | sed 's/\(.\)/ -\1/g') "$@"
            ;;
        *)
            usage_err
            ;;
    esac
done

if [ -z "$lxc_path" ]; then
    echo "$(basename $0): no configuration path defined" >&2
    exit 1
fi

if [ ! -r $lxc_path ]; then
    echo "$(basename $0): configuration path '$lxc_path' not found" >&2
    exit 1
fi

if [ -z "$lxc_orig" ]; then
    echo "$(basename $0): no original container name specified" >&2
    usage
    exit 1
fi

if [ -z "$lxc_new" ]; then
    echo "$(basename $0): no new container name specified" >&2
    usage
    exit 1
fi

if [ "$(id -u)" != "0" ]; then
   echo "$(basename $0): must be run as root" >&2
   exit 1
fi

if [ ! -d "$lxc_path/$lxc_orig" ]; then
    echo "$(basename $0): '$lxc_orig' does not exist" >&2
    exit 1
fi

if [ -d "$lxc_path/$lxc_new" ]; then
    echo "$(basename $0): '$lxc_new' already exists" >&2
    exit 1
fi

mounted=0
frozen=0
oldroot=`grep lxc.rootfs $lxc_path/$lxc_orig/config | awk -F= '{ print $2 '}`

cleanup() {
    if [ -b $oldroot ]; then
        if [ $mounted -eq 1 ]; then
            umount $rootfs || true
        fi
        lvremove -f $rootdev || true
    fi
    ${bindir}/lxc-destroy -n $lxc_new || true
    if [ $frozen -eq 1 ]; then
        lxc-unfreeze -n $lxc_orig
    fi
    echo "$(basename $0): aborted" >&2
    exit 1
}
trap cleanup HUP INT TERM

mkdir -p $lxc_path/$lxc_new
hostname=$lxc_new

echo "Tweaking configuration"
cp $lxc_path/$lxc_orig/config $lxc_path/$lxc_new/config
sed -i '/lxc.utsname/d' $lxc_path/$lxc_new/config
echo "lxc.utsname = $hostname" >> $lxc_path/$lxc_new/config

grep "lxc.mount[ \t]" $lxc_path/$lxc_new/config >/dev/null 2>&1 && { sed -i '/lxc.mount[ \t]/d' $lxc_path/$lxc_new/config; echo "lxc.mount = $lxc_path/$lxc_new/fstab" >> $lxc_path/$lxc_new/config; }

if [ -e  $lxc_path/$lxc_orig/fstab ];then
    cp $lxc_path/$lxc_orig/fstab $lxc_path/$lxc_new/fstab
    sed -i "s@$lxc_path/$lxc_orig@$lxc_path/$lxc_new@" $lxc_path/$lxc_new/fstab
fi

echo "Copying rootfs..."
oldroot=`grep lxc.rootfs $lxc_path/$lxc_orig/config | awk -F'[= \t]+' '{ print $2 }'`
rootfs=`echo $oldroot |sed "s/$lxc_orig/$lxc_new/"`

container_running=True
lxc-info -n $lxc_orig --state-is RUNNING || container_running=False

sed -i '/lxc.rootfs/d' $lxc_path/$lxc_new/config
if [ -b $oldroot ]; then
    which vgscan >/dev/null 2>&1 || { echo "$(basename $0): lvm is not installed" >&2; false; }
    lvdisplay $oldroot > /dev/null 2>&1 || { echo "$(basename $0): non-lvm blockdev cloning is not supported" >&2; false; }
    lvm=TRUE
    # ok, create a snapshot of the lvm device
    if [ $container_running = "True" ]; then
        lxc-freeze -n $lxc_orig
        frozen=1
    fi
    if [ $lxc_size = "_unset" ]; then
        lxc_size=`lvdisplay $oldroot | grep Size | awk '{ print $3 $4 }'`
    fi
    newlv="${lxc_lv_prefix}${lxc_new}_snapshot"
    lvcreate -s -L $lxc_size -n $newlv $oldroot
    which xfs_admin > /dev/null 2>&1 && {
        # change filesystem UUID if it is an xfs filesystem
        xfs_admin -u /dev/$lxc_vg/$newlv && xfs_admin -U generate /dev/$lxc_vg/$newlv
    }

    if [ $container_running = "True" ]; then
        lxc-unfreeze -n $lxc_orig
        frozen=0
    fi
    if [ $snapshot = "no" ]; then
        #mount snapshot
        mkdir -p ${rootfs}_snapshot
        mount /dev/$lxc_vg/${lxc_lv_prefix}${lxc_new}_snapshot ${rootfs}_snapshot || { echo "$(basename $0): failed to mount new rootfs_snapshot" >&2; false; }
        #create a new lv
        lvcreate -L $lxc_size $lxc_vg -n ${lxc_lv_prefix}$lxc_new
        echo "lxc.rootfs = /dev/$lxc_vg/${lxc_lv_prefix}$lxc_new" >> $lxc_path/$lxc_new/config
        # and mount it so we can tweak it
        mkdir -p $rootfs
        mkfs -t $fstype /dev/$lxc_vg/${lxc_lv_prefix}$lxc_new
        mount /dev/$lxc_vg/${lxc_lv_prefix}$lxc_new $rootfs || { echo "$(basename $0): failed to mount new rootfs" >&2; false; }
        mounted=1
        rsync -Hax ${rootfs}_snapshot/ ${rootfs}/ || { echo "$(basename $0): copying data to new lv failed" >&2; false; }
        umount ${rootfs}_snapshot
        rmdir ${rootfs}_snapshot
        lvremove -f $lxc_vg/${lxc_lv_prefix}${lxc_new}_snapshot
    else
        lvrename $lxc_vg/${lxc_lv_prefix}${lxc_new}_snapshot $lxc_vg/${lxc_lv_prefix}$lxc_new
        echo "lxc.rootfs = /dev/$lxc_vg/${lxc_lv_prefix}$lxc_new" >> $lxc_path/$lxc_new/config
        # and mount it so we can tweak it
        mkdir -p $rootfs
        mount /dev/$lxc_vg/${lxc_lv_prefix}$lxc_new $rootfs || { echo "$(basename $0): failed to mount new rootfs" >&2; false; }
        mounted=1
    fi

elif which btrfs >/dev/null 2>&1 && btrfs subvolume list $oldroot >/dev/null 2>&1; then
    # if oldroot is a btrfs subvolume, assume they want a snapshot
    btrfs subvolume snapshot "$oldroot" "$rootfs" 2>&1 || { echo "$(basename $0): btrfs snapshot failed" >&2; false; }
    echo "lxc.rootfs = $rootfs" >> "$lxc_path/$lxc_new/config"
else
    if [ $snapshot = "yes" ]; then
        echo "$(basename $0): cannot snapshot a directory" >&2
        cleanup
    fi
    if [ $container_running = "True" ]; then
        lxc-freeze -n $lxc_orig
        frozen=1
    fi
    mkdir -p $rootfs/ $rootfs.w/
    sed -i "1inone $rootfs/ aufs defaults,br=$rootfs.w/=rw:$oldroot/=r 0 0" $lxc_path/$lxc_new/fstab;
    mount -t aufs -o br=$rootfs.w/=rw:$oldroot/=r none $rootfs/
    mounted=1
    echo "lxc.rootfs = $rootfs" >> $lxc_path/$lxc_new/config
    if [ $container_running = "True" ]; then
        lxc-unfreeze -n $lxc_orig
        frozen=0
    fi
fi

echo "Updating rootfs..."

# so you can 'ssh $hostname.' or 'ssh $hostname.local'
if [ -f $rootfs/etc/dhcp/dhclient.conf ] && ! grep -q "^send host-name.*hostname" $rootfs/etc/dhcp/dhclient.conf; then
    sed -i "s/send host-name.*$/send host-name \"$hostname\";/" $rootfs/etc/dhcp/dhclient.conf
fi

c=$lxc_path/$lxc_new/config
# change hwaddrs
mv ${c} ${c}.old
(
while read line; do
    if echo $line | grep -q -w '^lxc.network.hwaddr'; then
        echo "lxc.network.hwaddr= 00:16:3e:$(openssl rand -hex 3| sed 's/\(..\)/\1:/g; s/.$//')"
    else
        echo "$line"
    fi
done
) < ${c}.old > ${c}
rm -f ${c}.old

# set the hostname
cat <<EOF > $rootfs/etc/hostname
$hostname
EOF
# set minimal hosts
cat <<EOF > $rootfs/etc/hosts
127.0.0.1 localhost $hostname
EOF

# if this was a block device, then umount it now
if [ $mounted -eq 1 ]; then
    umount $rootfs
fi

echo "'$lxc_new' created"