[Unit]
Description=Format EBS volume if needed
Before=etcd2.service

[Service]
ExecStart=/bin/bash -c \
  '(/usr/sbin/blkid -t TYPE=ext4 | grep /dev/xvdb) || \
  (/usr/sbin/wipefs -fa /dev/xvdb && /usr/sbin/mkfs.ext4 /dev/xvdb)'
RemainAfterExit=yes
Type=oneshot