[Unit]
Description=Set time via NTP using ntpdate
After=network-online.target nss-lookup.target
Before=time-sync.target
Wants=time-sync.target
Conflicts=systemd-timesyncd.service             

[Service]
Type=oneshot
ExecStart=/usr/sbin/ntpdate -b -u $SERVER
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target