[Unit]
# have it as  .service, not .swap, because .swap has implicit dependency on
# .device which needs udev running already
Description=Enable swap on /dev/xvdc1 early
DefaultDependencies=no
Before=systemd-fsck-root.service

[Service]
Type=oneshot
ExecStart=-/usr/sbin/swapon /dev/xvdc1

[Install]
WantedBy=sysinit.target