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
- How do I check Linux system’s current NTP configuration
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
[root@tpemimtst99 ~]# timedatectl
Local time: Tue 2021-05-25 09:09:09 CST
Universal time: Tue 2021-05-25 01:09:09 UTC
RTC time: Tue 2021-05-25 01:09:09
Time zone: Asia/Taipei (CST, +0800)
System clock synchronized: yes
NTP service: active
RTC in local TZ: no
[root@tpemimtst99 ~]# chronyc sources
210 Number of sources = 1
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^* 192.168.21.86 3 10 377 754 +1543ns[+4123ns] +/- 63ms
systemd-timesyncd
Build-in on Ubuntu
timedatectl
# See the information of the datetime
timedatectl
# List timezones supported
timedatectl list-timezones
# Change the system’s timezone
sudo timedatectl set-timezone Asia/Taipei
ntpd
Install
# Ubuntu
sudo apt install ntp
vi /etc/ntp.conf
#pool 0.ubuntu.pool.ntp.org iburst
#pool 1.ubuntu.pool.ntp.org iburst
#pool 2.ubuntu.pool.ntp.org iburst
#pool 3.ubuntu.pool.ntp.org iburst
# Use Ubuntu's ntp server as a fallback.
#pool ntp.ubuntu.com
# Added the local time server
server 192.168.21.86 prefer iburst
Restart the ntpd
# Ubuntu 16.04
systemctl stop ntp
systemctl start ntp
# Check the timeserver
ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
0.ubuntu.pool.n .POOL. 16 p - 64 0 0.000 0.000 0.000
1.ubuntu.pool.n .POOL. 16 p - 64 0 0.000 0.000 0.000
2.ubuntu.pool.n .POOL. 16 p - 64 0 0.000 0.000 0.000
3.ubuntu.pool.n .POOL. 16 p - 64 0 0.000 0.000 0.000
ntp.ubuntu.com .POOL. 16 p - 64 0 0.000 0.000 0.000
+eterna.binary.n 216.218.192.202 2 u 32 64 3 45.986 -0.081 0.021
+pacific.latt.ne 193.187.181.6 3 u 30 64 3 8.205 1.151 0.026
-mis.wci.com 216.218.192.202 2 u 32 64 3 37.928 4.692 0.176
-europa.ellipse. 209.180.247.49 2 u 31 64 3 51.792 4.175 0.027
#38.229.56.9 172.16.21.35 2 u 30 64 3 68.917 -4.451 0.190
#time.richiemcin 97.183.206.88 2 u 29 64 3 69.281 -3.073 0.248
*t1.time.gq1.yah 208.71.46.33 2 u 30 64 3 31.630 -0.081 0.011
-lofn.fancube.co 220.181.254.66 2 u 30 64 3 37.871 -1.088 0.009
#2606:6680:8:1:: 107.46.198.112 2 u 26 64 3 198.284 66.201 0.061
-titan.crash-ove 129.7.1.66 2 u 30 64 3 32.708 -1.474 0.200
-2620:1d5:100:43 47.187.174.51 2 u 29 64 3 70.418 0.592 0.197
2001:67c:1560:8 17.253.34.123 2 u 32 64 3 133.490 -2.818 0.030
#38.229.57.9 172.16.21.35 2 u 30 64 3 177.896 4.081 6.291
#ntp2i.versadns. 217.180.209.214 2 u 28 64 3 62.795 -2.897 0.017
-104.194.8.227 192.12.19.20 2 u 25 64 3 0.979 -0.737 0.029
-pacific.latt.ne 193.187.181.6 3 u 26 64 3 8.770 1.212 0.050
2001:67c:1560:8 17.253.34.123 2 u 33 64 3 133.602 -2.792 0.007