lmn-client/roles/lmn_vm/files/rebase-vm.sh
2023-08-14 21:07:32 +02:00

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#!/usr/bin/bash
# Rebase one level down
set -eu
show_help() {
cat << EOF >&2
Usage: $(basename "$0") [-n newname] vmname"
This script takes as input the name of the VM to rebase one level down
-n new name of the rebased image
EOF
}
while getopts ':n:' OPTION; do
case "$OPTION" in
n)
NEWNAME=$OPTARG
;;
?)
show_help
exit 1
;;
esac
done
shift "$((OPTIND -1))"
# if less or more than one arguments supplied, display usage
if [[ $# -ne 1 ]]; then
show_help
exit 1
fi
# change to Images directory
VM_DIR="/tmp/${UID}/vm"
cd "${VM_DIR}"
VM_NAME="$1"
# check if VM-Diskimage exists
if [[ ! -f "${VM_NAME}.qcow2" ]]; then
echo "File not found ${VM_NAME}.qcow2" >&2
exit 1
fi
# check if new VM-Diskimage exists
if [[ -v NEWNAME ]] && [[ -f "${NEWNAME}.qcow2" ]]; then
echo "New Base already exists: ${NEWNAME}.qcow2" >&2
exit 1
fi
NUMBASES=$(qemu-img info --backing-chain "${VM_NAME}.qcow2" | grep -c image)
NEWBASE=$(qemu-img info --backing-chain "${VM_NAME}.qcow2" | grep image | head -n 3 | tail -n 1 | cut -d' ' -f2)
CURRENTBASE=$(qemu-img info --backing-chain "${VM_NAME}.qcow2" | grep image | head -n 2 | tail -n 1 | cut -d' ' -f2)
if [[ ! "${NUMBASES}" -ge 3 ]]; then
echo "Image must have at least 2 backing-files" >&2
exit 1
fi
# check if base Diskimage exists
if [[ ! -f "${NEWBASE}" ]] || [[ ! -f "${CURRENTBASE}" ]]; then
echo "Backingfiles not found ${CURRENTBASE}, ${NEWBASE}" >&2
exit 1
fi
# rebasing disk image
qemu-img rebase -f qcow2 -b "${NEWBASE}" -F qcow2 "${VM_NAME}.qcow2"
if [[ -v NEWNAME ]]; then
# copy and adapt machine definition file
CURRENTNAME="${CURRENTBASE/.qcow2/}"
if [[ -f "${CURRENTNAME}.xml" ]]; then
cp "${CURRENTNAME}.xml" "${NEWNAME}.xml"
elif [[ -f "/lmn/vm/${CURRENTNAME}.xml" ]]; then
cp "/lmn/vm/${CURRENTNAME}.xml" "${NEWNAME}.xml"
else
echo "no machine definition file found" >&2
exit 1
fi
sed -i "s/${CURRENTNAME}/${NEWNAME}/" "${NEWNAME}.xml"
NEWNAME="${NEWNAME}.qcow2"
else
rm "${CURRENTBASE}"
NEWNAME="${CURRENTBASE}"
fi
mv "${VM_NAME}.qcow2" "${NEWNAME}"
chmod a-w "${NEWNAME}"