校時與時區設定

Chrony

Built-in on CentOS

• CHAPTER 18. CONFIGURING NTP USING THE CHRONY SUITE
• CentOS / RHEL 7 : Configuring NTP using chrony

Install

yum install chrony

Config: /etc/chrony.conf

# NTP Public Servers for Taiwan
server tw.pool.ntp.org
server time.stdtime.gov.tw
server clock.stdtime.gov.tw
server jp.pool.ntp.org

# Allow NTP client access from local network.
#allow 192.168.0.0/16

Starting

systemctl start chronyd

Verify

[root@localhost ~]# chronyc tracking
Reference ID    : 7A75FDF6 (static.home.twn.sciuridae.cloud)
Stratum         : 3
Ref time (UTC)  : Sun Aug 16 03:35:36 2020
System time     : 0.000073180 seconds slow of NTP time
Last offset     : -0.001259724 seconds
RMS offset      : 0.001259724 seconds
Frequency       : 21.057 ppm slow
Residual freq   : -0.000 ppm
Skew            : 28.166 ppm
Root delay      : 0.032856792 seconds
Root dispersion : 0.002069760 seconds
Update interval : 64.3 seconds
Leap status     : Normal

systemd-timesyncd

Build-in on Ubuntu

• Control your computer time and date with systemd