ntpdate is a historical ntp synchronization client for unixes. It sould be uninstalled.
ntpdate is an old not security-compliant ntp client. It should be replaced by modern ntp clients such as ntpd, able to use cryptographic mechanisms integrated in NTP.
The ntpdate service sets the local hardware clock by polling NTP servers
when the system boots. It synchronizes to the NTP servers listed in
/etc/ntp/step-tickers or /etc/ntp.conf
and then sets the local hardware clock to the newly synchronized
system time.
The ntpdate service can be disabled with the following command:
$ sudo systemctl mask --now ntpdate.service
The ntpdate service may only be suitable for systems which are rebooted frequently enough that clock drift does not cause problems between reboots. In any event, the functionality of the ntpdate service is now available in the ntpd program and should be considered deprecated.