chrony

chrony

prerequisite:

firewalld

• firewall-cmd --state

• firewall-cmd --list-all

  

   

   

   

• firewall-cmd --zone=public --query-port=123/tcp firewall-cmd --zone=public --query-port=123/udp 
  

   

   

   

• firewall-cmd --zone=public --add-service=ntp --permanent

• firewall-cmd --zone=public --add-port=123-125/tcp --permanent

• firewall-cmd --zone=public --add-port=123/udp --permanent

• firewall-cmd --reload

• firewall-cmd --zone=public --list-service

• firewall-cmd --zone=public --list-port

• firewall-cmd --zone=public --query-service=ntp

• firewall-cmd --zone=public --remove-port=123/tcp --permanent

• /etc/firewalld user profile /usr/lib/firewalld 系统配置文件，预置文件

• firewall-cmd --panic-on reject all packages firewall-cmd --panic-off firewall-cmd --query-panic

• firewall-cmd --get-active-zone 

• 

   

   

timedatectl

• timedatectl set-ntp true

  

   

   

  NTP synchronized:no ntp不能同步时间

chronyc

1. A client/server for network time protocol,It was specially designed to support systems with intermittent internet connections.It can also use hardware clocks,system real-time clock or manual input as time references.

• rpm -ql chrony man chrony.conf

  • /etc/chrony.conf

  • /usr/bin/chronyc

  • /usr/sbin/chronyd

2. chrony.conf

   cp chrony.conf{,.bak}

   server ntp.api.bz iburst

   server ntp.aliyum.com iburst

   all 192.168.3.0/24

   deny 192.168.8.0/24

3. chronyc

   • chronyc -v 
     

      

      

      

   •  

   • chronyc sources v display information about current sources

     

      

      

      

   • chronyc sourcestats v display statistics about collected measurements

     

      

      

   • chronyc activity v check how many NTP sources are online/offline 
     

      

      

      

   • chronyc tracking v display system time information 
     

      

      

      

   • chronyc clients v Report on clients that have accessed the server

     

      

      

   • 

      

      

   • chronyc ntpdata v Display information about last valid measurement

     

      

      

   • 

      

      

     /etc/chrony.conf中 
     

      

      

      

     定义了本机时间未同步时的stratum为10

   很多人主要使用 ntpdate 同步时间， 但使用ntpdate同步时间，会造成时间的跳跃，对一些依赖时间的程序和服务会造成影响。 所以理想的做法为，在开机的时候，使用ntpdate强制同步时间，在其他时候使用ntpd服务来同步时间,