安装 NTP 服务
#
[root@xuxing ~]# yum -y install ntp
修改配置文件
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[root@xuxing ~]# cat /etc/ntp.conf | grep -v ^# | grep -v ^$
driftfile /var/lib/ntp/drift
restrict default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery
restrict 127.0.0.1
restrict ::1
restrict 10.0.0.0 mask 255.0.0.0 nomodify notrap <<<<< 选择ntp server 服务的client 范围
server 1.ntp.esl.cisco.com iburst <<<<< server 去网站https://www.pool.ntp.org/zone/asia选取对应地区server
server 2.ntp.esl.cisco.com iburst
server 3.ntp.esl.cisco.com iburst
includefile /etc/ntp/crypto/pw
keys /etc/ntp/keys
disable monitor
[root@xuxing ~]#
添加防火墙规则并重启
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[root@xuxing ~]# firewall-cmd --add-service=ntp --permanent
[root@xuxing ~]# firewall-cmd --reload
[root@xuxing ~]# systemctl start ntpd
[root@xuxing ~]# systemctl enable ntpd
[root@xuxing ~]# systemctl status ntpd
检查 server 状态
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[root@xuxing ~]# ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
*bgl11-row1-dc-n .GNSS. 1 u 59 64 37 128.524 0.521 0.301
+mtv5-ai27-dcm10 .GNSS. 1 u 49 64 77 191.412 2.389 0.507
+mtv5-ai27-dcm10 .GNSS. 1 u 21 64 77 192.614 1.762 0.420
[root@xuxing ~]# ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
*bgl11-row1-dc-n .GNSS. 1 u 66 64 37 128.524 0.521 0.301
+mtv5-ai27-dcm10 .GNSS. 1 u 56 64 77 191.412 2.389 0.507
+mtv5-ai27-dcm10 .GNSS. 1 u 28 64 77 192.614 1.762 0.420
[root@xuxing ~]#
[root@xuxing ~]#
[root@xuxing ~]# date -R
Mon, 30 Mar 2020 12:20:21 -0400
<<<<< 一些参数解释解释
when Time since last NTP packet was received from peer, in milliseconds.
poll Polling interval, in seconds.
reach Peer reachability (bit string, in octal).
delay Round-trip delay to peer, in milliseconds.
offset Relative time difference between a peer clock and a local clock, in milliseconds.