import-layers/meta-openembedded/meta-networking/recipes-support/ntp/ntp/ntpdate.service

[Unit]
Description=Network Time Service (one-shot ntpdate mode)
Before=ntpd.service

[Service]
Type=oneshot
ExecStart=/usr/bin/ntpdate-sync silent
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target