Configure A System To Use Time Services

General Information

Managing time using different methods.

• ntpd ⇒ the default in RHEL 5/6
• chronyd ⇒ the default in RHEL 7 (ntpd can still be used instead)
  • Chronyd has faster time sync than ntpd and can recover from network connection problems faster.

Two new RHEL 7 tools:

• chronyd - new red hat 7 time daemon (ntpd was previous daemon)
• timedatectl - time and date settings information

View current detailed time information

timedatectl

View available timezones

timedatectl list-timezones

Set timezone

timedatectl set-timezone America/Chicago

Set system clock to 12:30pm and 10 seconds:

timedatectl set-time 12:30:10

Enable the use of NTP for time

timedatectl set-ntp true

NTP service config file (chronyd)

• /etc/chrony.conf

NTP server entry examples in /etc/chrony.conf

server 0.pool.ntp.org iburst
server 1.pool.ntp.org iburst
server 2.pool.ntp.org iburst
server 3.pool.ntp.org iburst

• If you make any changes, chronyd service must be restarted

Check status of NTP service, Restart it

systemctl status chronyd
systemctl restart chronyd

View NTP sources

chronyc sources -v