#!/bin/bash 

# depends on following packages:
# apt-get install virtinst libvirt-bin dosfstools mtools kvm xmlstarlet

# For resizing the root partition we tried two ways: 

# sfdisk 
# ------
# For sfdisk we need util-linux >= 2.17.2-3 (debian wheezy, ubuntu oneiric), 
# because of the sfdisk-feature which lets us script the growing of the root partition.
# see https://bugs.launchpad.net/ubuntu/+source/util-linux/+bug/686124
# apt-get install -t wheezy util-linux

# parted
# ------
# seems to be more robust than sfdisk, so we use that approach
# unfortunatly, there's no way to resize a partition with parted >= 2.4
# deleting and recreating is the only way, which leaves us with an 
# dirty workaround, giving the beginning of the root partition in sectors
# with the variable $ROOT_PARTITION_BEGINNING


# defaults, configurable in config
VG='vg01'
ETC='/etc/libvirt/local/cloudinit'
CONFIG="$ETC/cloudinit.cfg"
VARDIR='/var/lib/libvirt/cloudinit'
SCRIPTDIR='/usr/local/bin/leap_cloudadmin'
KVM_URI='qemu:///system'
SEED='cloudinit_seed.img'

BASEIMAGE='leap-baseimage'
SWAPUUID='3a79d708-2a74-4344-a953-15e955dbdae7'

# Defaults for leap-baseimage, change if you 
# have a different disk layout 
ROOT_PARTITION_NR='2'
ROOT_PARTITION_BEGINNING='4096s'

# unconfigurable variables
MIN_ROOTSIZE=2
DEFAULT_SWAPSIZE=512
DEFAULT_MEM=512
rootsize=$MIN_ROOTSIZE
swapsize=$DEFAULT_SWAPSIZE
memsize=$DEFAULT_MEM


# overwrite defaults
[ -e $CONFIG ] && . $CONFIG

[ -z "$LC_ALL" ] && LC_ALL="en_US.UTF-8"


fail() { [ $# -eq 0 ] || echo "$@"; exit 1; }
bad_usage() { usage 1>&2; [ $# -eq 0 ] || fail "$@"; exit 1; }

usage() {
       cat <<EOF

Usage: ${0##*/} -r <gb> -s <mb> -n guest_name

  Creates a new guest VM using cloud-init to utilize nocloud.
  Uses $ETC/<guest_name>.cfg as meta- und user-data file  

  options:
    -h             show usage
    -r size        root size in GB. Defaults to minimal value of $MIN_ROOTSIZE GB.
    -s size        swap size in MB. Defaults to $DEFAULT_SWAPSIZE MB.
    -m size        memory size in kibibytes. Defaults to $DEFAULT_MEM KiB.
    -n name	   guestname
EOF
}


# Parse cmdline options

while getopts "hr:s:n:m:" OPTION
do
  #echo $OPTION $OPTARG
  case $OPTION in
     h) usage
        exit 0;;
     r) rootsize=$OPTARG;; 
     s) swapsize=$OPTARG;;
     n) vmname=$OPTARG;; 
     m) memsize=$OPTARG;; 
   esac
done

[ -z $vmname  ] && bad_usage "must provide guest name"
[ $# -gt 8 ] && bad_usage "too many arguments"
[ $rootsize -lt $MIN_ROOTSIZE ] && bad_usage "Minimal root size is $MIN_ROOTSIZE GB !"


cfg="$ETC/$vmname.cfg"
rootdev="/dev/$VG/${vmname}-root"
swapdev="/dev/$VG/${vmname}-swap"

# requirements
echo "mtools_skip_check=1">~/.mtoolsrc
[ -e $VARDIR ] || ( mkdir $VARDIR ; chown libvirt-qemu $VARDIR )

[ -e $rootdev ] && fail "$rootdev exists - please delete it or choose another guest name"
[ -e $swapdev ] && fail "$swapdev exists - please delete it or choose another guest name"
[ -e $cfg ] ||  fail "please provide config file in $cfg"

echo
echo "Creating guest VM $vmname:"
echo "Root size: $rootsize GB, using $rootdev"
echo "Swap size: $swapsize MB, using $swapdev"
echo "Memory size: $memsize KiB"
echo ""
echo "using $cfg for cloud-init"
echo
echo "OK ? <Ctrl-C> to abort, <enter> to resume."
read enter

# is a VM with the same name defined ?
virsh dominfo $vmname > /dev/null 2>&1
if [ $? -eq 0 ]; then fail "Domain $vmname is defined in libvirt. Please undefine first."; fi

# create root and swap disk
lvcreate -L ${rootsize}g -n ${vmname}-root $VG
lvcreate -L ${swapsize}m -n ${vmname}-swap $VG
mkswap  -U $SWAPUUID $swapdev

sleep 4 
virt-clone --connect $KVM_URI -o $BASEIMAGE -n $vmname -f $rootdev  --force

# Set memory
tmpxml=`mktemp`
virsh dumpxml ${vmname} > $tmpxml
xmlstarlet edit -L -u "/domain[@type='kvm']/memory[@unit='KiB']" -v "${memsize}" $tmpxml
virsh define $tmpxml
rm -f $tmpxml

# resize root partition

# echo ",+," | sfdisk -q -N2  /dev/$VG/$vmname > /dev/null 2>&1
# sfdisk is unreliable for us and doesn't work on a new kvm host
parted $rootdev --script -- rm $ROOT_PARTITION_NR
parted $rootdev --script -- mkpart primary $ROOT_PARTITION_BEGINNING -1s

# create cloudinit seed disk 
csplit -q --prefix "$VARDIR/$vmname" $cfg '/#cloud-config/'
metadata="$VARDIR/${vmname}00"
userdata="$VARDIR/${vmname}01"
$SCRIPTDIR/libvirt-make-seed-disk $VARDIR/$vmname-$SEED $userdata $metadata


echo
echo "Cloudinit-seeddisk is at $VARDIR/$vmname-$SEED, attaching after booting"
echo
echo "Finished creating guest $vmname. Enjoy."
echo
echo "Press <return> to start the new guest."
read bogus

echo
echo 'Starting new guest, attaching to console. Exit with Ctrl+]'
echo

virsh start $vmname
sleep 2 

# create seed- and swapdisk definition and attach them
virsh attach-disk $vmname --source $swapdev --target vdb  --config
virsh attach-disk $vmname --source $VARDIR/$vmname-$SEED --target vdc --sourcetype file --type disk --driver qemu --subdriver raw --config
virsh setmem $vmname $memsize --live --config

virsh console $vmname