linuxexpert-practice-labs/labs/lpic-1/108-1-system-time/README.md

LPIC-1 108.1: Maintaining system time

Which NTP client runs, the hardware clock, and chrony's sources.

Before you start

The lab notes which NTP client runs now, and saves chrony's configuration (if chrony is installed) so reset can put it back. Changing the NTP sources needs the VM to reach the internet on UDP port 123 to see them work, but the check doesn't depend on that.

Tasks

1. Run timedatectl and find out which NTP client the VM uses (systemctl status chronyd chrony systemd-timesyncd). Write the name of its service to /root/lab-answers/1.
2. Compare sudo hwclock with date -u. Then read /etc/adjtime, if it exists. Write utc or local to /root/lab-answers/2: the time the hardware clock keeps.
3. Install chrony if it isn't there (it replaces timesyncd), and read chronyc sources -v and chronyc tracking. Then change chrony's sources to just the pool pool.ntp.org, restart it, and watch the sources change with chronyc sources.

Hints

• systemctl is-active chronyd chrony systemd-timesyncd.
• The third line of /etc/adjtime says UTC or LOCAL; without the file, the hardware clock is taken to be UTC. timedatectl shows it as "RTC in local TZ".
• /etc/chrony.conf on the RHEL family; /etc/chrony/chrony.conf and its sources.d directory on Debian and Ubuntu. Comment out the other pool and server lines. chronyc -N sources shows the names.