[Unit]
Description=Set time via SNTP
After=network.target NetworkManager-wait-online.service nss-lookup.target
Before=time-sync.target
Wants=time-sync.target
Conflicts=systemd-timesyncd.service             

[Service]
Type=oneshot
ExecStart=/usr/bin/sntp -s $SERVER
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target