時刻表示 NTPサーバー設定
[root@falcon21 ~]# vi /etc/ntp.conf
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
#server 0.centos.pool.ntp.org iburst
#server 1.centos.pool.ntp.org iburst
#server 2.centos.pool.ntp.org iburst
#server 3.centos.pool.ntp.org iburst
server ntp.nict.jp
server ntp.jst.mfeed.ad.jp
server ntp.asahi-net.or.jp
# Record the rate at which the system clock gains/losses time.
driftfile /var/lib/chrony/drift
# Allow the system clock to be stepped in the first three updates
# if its offset is larger than 1 second.
makestep 1.0 3
# Enable kernel synchronization of the real-time clock (RTC).
rtcsync
# Enable hardware timestamping on all interfaces that support it.
#hwtimestamp *
# Increase the minimum number of selectable sources required to adjust
# the system clock.
#minsources 2
# Allow NTP client access from local network.
#allow 192.168.0.0/16
# Serve time even if not synchronized to a time source.
#local stratum 10
# Specify file containing keys for NTP authentication.
#keyfile /etc/chrony.keys
# Specify directory for log files.
logdir /var/log/chrony
# Select which information is logged.
#log measurements statistics tracking
NTPサーバー起動
[root@falcon21 ~]# ntpdate ntp.nict.jp
15 Feb 13:57:52 ntpdate[7037]: adjust time server 133.243.238.244 offset 0.000800 sec
[root@falcon21 ~]# systemctl start chronyd
[root@falcon21 ~]# systemctl enable chronyd
NTPサーバー確認
[root@falcon21 ~]# chronyc sources
210 Number of sources = 4
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^+ ntp-b3.nict.go.jp 1 10 377 639 -218us[ -218us] +/- 7941us
^* ntp-a2.nict.go.jp 1 10 377 772 -669us[ -962us] +/- 9109us
^- ntp.paina.net 2 10 277 822 -163us[ -455us] +/- 48ms
^- ntp2.jst.mfeed.ad.jp 2 10 377 485 -1089us[-1089us] +/- 81ms