Good article but out of date. On a 2021 Linux system you want to install chrony, not ntpd. And for goodness sake make sure systemd isn’t trying to manage the clock; installing chrony should do that. I also quibble with the article just relying on NTP Pool servers; that’s fine for a few systems but if you’re running a lot of servers in a single datacenter it’s worth setting up a local NTP server hierarchy.
I haven’t been to the other parts yet, but I do hope that kind of dependency would be caught in an audit of a dc. At that point you need some more robust method for time source to avoid other issues.
I’m wondering if the authored covered time and virtualization. That was something of a fret when I was younger and it’s a topic that is very valid today.
Part 2: https://libertysys.com.au/2016/10/the-school-for-sysadmins-who-cant-timesync-good-and-wanna-learn-to-do-other-stuff-good-too-part-2-how-ntp-works/
And Part 3: https://libertysys.com.au/2016/10/the-school-for-sysadmins-who-cant-timesync-good-and-wanna-learn-to-do-other-stuff-good-too-part-3-ntp-installation-and-configuration/
And part 5 - myths, misconceptions, and best practices