Cloud init service block to conditionally format an unformatted volume.

cloud-init-format-volume.yaml

name: format-volume.service
command: start
content: |
  [Unit]
  Description=Formats the volume drive
  Requires=dev-vdb.device
  After=dev-vdb.device
  ConditionFirstBoot=true

  [Service]
  Type=oneshot
  RemainAfterExit=yes
  ExecStart=/usr/bin/bash -xc "\
    (/usr/bin/lsblk --fs | /usr/bin/grep vdb1 | /usr/bin/grep --silent ext4) || (\
      /usr/sbin/parted --machine --script /dev/vdb mklabel gpt &&\
      /usr/sbin/parted --machine --script --align=opt /dev/vdb mkpart primary ext4 0% 100% &&\
      /usr/sbin/mkfs.ext4 -L VOLUME-A /dev/vdb1)"