Create an openVZ template (tar ball) from a running CT

vztmpl-cr

#!/bin/bash

## Create an openVZ template (tar ball) from a running CT 

set -eo pipefail

if [ -z $1 ]
then
        echo "Usage: vztmpl-cr CTID [NAME]"
        exit 1
fi

main() {

  local CTID="$1"
  local OSTEMPLATE="$(vzlist -Ho ostemplate ${CTID})"
  local DEFAULT_NAME="${OSTEMPLATE}_${CTID}_$(date +%F)"
  local NAME="/tmp/${2:-$DEFAULT_NAME}"
  
  # Known snapshot ID
  local ID=$(uuidgen)
  
  # Directory used to mount the snapshot
  local MNTDIR="$(mktemp -d)"
  
  # Take a snapshot without suspending a CT and saving its config
  vzctl --quiet snapshot $CTID --id $ID --skip-suspend --skip-config \
  || exit 3
  
  # Mount the snapshot taken
  vzctl --quiet snapshot-mount $CTID --id $ID --target $MNTDIR \
  || exit 3
  
  # Create the template tar ball from the mounted snapshot
  GZIP=-9 tar zcf "${NAME}.tar.gz" -C $MNTDIR --warning=none . \
  || exit 3
  
  # Unmount the snapshot
  vzctl --quiet snapshot-umount $CTID --id $ID \
  || exit 3
  
  # Delete (merge) the snapshot
  vzctl --quiet snapshot-delete $CTID --id $ID \
  || exit 3
  
  # Delete MNTDIR
  rm -rf $MNTDIR
  
  # Output template path
  echo "${NAME}.tar.gz"

}

main "$@"