问题
After I installed ntpd via yum I run the command systemctl enable ntpd.service and rebooted the computer. After I got the shell prompt I run systemctl -a | grep ntp and I got ntpd.service loaded inactive dead. If I start it manually using systemctl start ntpd.service it works fine. Why is that? How can I ensure the ntpd.service will be up and running after reboot?
回答1:
This appears to be an issue with fedora, there is a service named "chrony" which prevents ntpd service to start after boot. After removing chrony with yum, ntpd service is started after boot. For more details you can check this.
UPDATE: You can also disable the chronyd that runs on port 123 and then ntpd will start:
sudo systemctl disable chronyd
sudo systemctl start ntpd
来源：https://stackoverflow.com/questions/22779584/why-ntpd-service-is-not-started-automatically-after-reboot