CentOS8中默认已经不再支持ntpd软件包，同时也无法通过官方软件仓库安装， CentOS8上使用Chrony配置NTP服务器，用于同步时间。 它有两个程序，chrony和chronyd， chronyd是守护进程 ，chrony是一个命令行界面程序，可以用来监控chronyd的性能，并修改各种操作参数。
安装chrony
系统会默认安装并启动，如果系统不存在则需要安装此工具库。
仓库中直接安装
dnf -y install chrony
启动守护进程
systemctl enable –now chronyd
时间同步配置
设置时区
联网的情况下一般设置时区后会通过网络同步时间
timedatectl set-timezone "Asia/Shanghai"
配置chrony.conf
修改配置加入aliyun pool网络时间，也可以加入多个pool服务器
vim /etc/chrony.conf
# Use public servers from the pool.ntp.org project. # Please consider joining the pool (http://www.pool.ntp.org/join.html). pool 2.centos.pool.ntp.org iburst pool ntp.aliyun.com iburst # 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 # Get TAI-UTC offset and leap seconds from the system tz database. leapsectz right/UTC # Specify directory for log files. logdir /var/log/chrony # Select which information is logged. #log measurements statistics tracking
重新加载配置
systemctl restart chronyd.service
时间同步
执行时间同步命令
chronyc sources -v
[root@k8smaster ~]# chronyc sources -v
210 Number of sources = 5
.-- Source mode ‘^’ = server, ‘=’ = peer, ‘#’ = local clock.
/ .- Source state ‘*’ = current synced, ‘+’ = combined , ‘-’ = not combined,
| / ‘?’ = unreachable, ‘x’ = time may be in error, ‘~’ = time too variable.
|| .- xxxx [ yyyy ] +/- zzzz
|| Reachability register (octal) -. | xxxx = adjusted offset,
|| Log2(Polling interval) --. | | yyyy = measured offset,
|| \ | | zzzz = estimated error.
|| | |
MS Name/IP address Stratum Poll Reach LastRx Last sample
^- ntp5.flashdance.cx 2 6 377 6 +8255us[+8255us] +/- 139ms
^- 185.216.231.25 2 7 13 6 +10ms[ +10ms] +/- 98ms
^- 119.28.206.193 2 6 377 9 +1016us[+1001us] +/- 62ms
^* dns1.synet.edu.cn 2 6 377 8 -1423us[-1438us] +/- 9294us
^+ 203.107.6.88 2 6 377 7 +2107us[+2107us] +/- 17ms
验证查看时间
查看当前系统时间
date