In my Fedora 19 I've been wondering why my NTPd does not start on boot. It used to do so couple of Fedora installations ago. This is not a big deal, so I've been mostly ignoring it. Today I dug up some energy to investigate.
The reason was much simpler than I tought. On my very short checklist were:
- Confirm that systemd has ntpd.service enabled, it was.
- Confirm that ntpd.service has a dependency to start the service after network interfaces are up, it was chained to do a single ntpdate update and start the daemon after it.
- Needed interfaces have not been blocked and/or needed interfaces have been enabled in config, everything was out-of-the-box: all network interfaces allowed.
The daemon even had the panic-threshold disabled in the config, so it wouldn't choke on startup if time was badly off for some reason. I found no reason for the daemon to start.
However, doing a search for ntpd in /usr/lib/systemd/system revealed what was going on. chronyd.service has Conflicts=ntpd.service in the service description. WTF?! What the hell is chronyd?
According to http://chrony.tuxfamily.org/ it is "a pair of programs which are used to maintain the accuracy of the system clock on a computer". Sounds like a NTPd to me. 
Running netstat confirmed the fact:
# netstat -nap | fgrep :123
udp 0 0 0.0.0.0:123 0.0.0.0:* 666/chronyd
udp6 0 0 :::123 :::* 666/chronyd
The daemon does bind to NTP-ports. To get chronyd running properly, all I had to do was add proper time source and allowed updates from my LAN with allow-directives.
That's it!