It's TIME
Network Time Protocol
Network Time Protocol Daemon
Also referred to as ntpd because it's a daemon.
There's a new system called systemd-timesyncd (Is it default now on Ubuntu?) ntpd is more accurate [1] so it's better to stick with that if you have a system that is RTOS. Timesyncd is a client-only implementation and may be more suitable for most installations.
If you don't know what time it is, then how can you run cron?! Don't let your system get out of sync.
See
- http://doc.ntp.org/4.2.6/ntpd.html?advanced=on Docs
- https://help.ubuntu.com/lts/serverguide/NTP.html
- https://wiki.archlinux.org/index.php/Network_Time_Protocol_daemon
- https://www.digitalocean.com/community/tutorials/how-to-set-up-time-synchronization-on-ubuntu-16-04
- https://www.us-cert.gov/ncas/current-activity/2017/03/22/Vulnerabilities-Identified-Network-Time-Protocol-Daemon-ntpd