開始之前先把firewalld和selinux關閉
[root@localhost ~]# systemctl stop firewalld.service
[root@localhost ~]# setenforce 0 #臨時關閉selinux 立即生效
[root@localhost ~]# vim /etc/selinux/config
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
# enforcing - SELinux security policy is enforced.
# permissive - SELinux prints warnings instead of enforcing.
# disabled - No SELinux policy is loaded.
SELINUX=disabled #永久關閉 重啓生效
# SELINUXTYPE= can take one of these two values:
# targeted - Targeted processes are protected,
# minimum - Modification of targeted policy. Only selected processes are protected.
# mls - Multi Level Security protection.
SELINUXTYPE=targeted配置源的部分就不說了
安裝
[root@localhost ftp]# yum install ntp -y
已加載插件：langpacks, product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
正在解決依賴關係
--> 正在檢查事務
---> 軟件包 ntp.x86_64.0.4.2.6p5-18.el7 將被 安裝
--> 解決依賴關係完成
依賴關係解決
--------------省略部分--------------
已安裝:
ntp.x86_64 0:4.2.6p5-18.el7
完畢！
配置
在配置文件/etc/ntp.conf中修改
restrict 10.0.0.0 mask 255.0.0.0 nomodify notra
授權10.0.0.0網段上的所有機器可以從這臺機器上查詢和同步時間.
#Please consider joining the pool (http://www.pool.ntp.org/join.html).
#server 0.rhel.pool.ntp.org iburst
#server 1.rhel.pool.ntp.org iburst
#server 2.rhel.pool.ntp.org iburst
#server 3.rhel.pool.ntp.org iburst
如果ntp服務器無法聯網，可以把從外網同步時間註釋掉。
server 127.127.1.0 # local clock
fudge 127.127.1.0 stratum 10
當外部時間不可用時，使用本地時間.
啓動
[root@localhost ~]# systemctl start ntpd.service測試
[root@localhost ~]# date
2019年 03月 14日 星期四 01:11:01 CST
[root@localhost ~]#