Operating System

Subtopics 
 
 How to check if the system is synchronized? 
 How to configure RHEL7 with ntp ? 
 How to configure RHEL9 with chrony ? 
 
 How to check if the system is synchronized? 
 On RHEL7 the time synchronization is done via ntp and on RHEL9 via chrony . For license checkout either the license server(s) and the clients need to be synchronized timely. 
 Please check with  
 timedatectl 
 if the system is synchronized . 
 
 
 
 
 
 
 
 timedatectl output 
 
 
 
 In the screenshot above the system is not configured for time synchronization and ntp is disabled. 
 How to configure RHEL7 with ntp? 
 Note : In general customer IT is responsible to set up the time synchronization. The information below is just for your convenience, but is not part of GLPT support. 
 Prerequisite:  
 You need a reliable time server.  
 Steps to be checked: 
 
 
 Check if ntp is installed with rpm -q ntp If it is not installed, you can try to get it with sudo yum install ntp 
 
 
 open /etc/ntp.conf with an editor (you need editing permissions or sudo rights) Here you can add the NTP server with adding the line server hostname iburst Example : server time.google.com iburst 
 
 
 Check if ntp service is enabled / started with systemctl status ntpd If it is not started / enabled 
 
 
 Enable ntp service for being started with a reboot: sudo systemctl enable ntpd 
 
 
 Start ntp service with sudo systemctl start ntpd 
 
 
 
 
 Check the time synchronization:  sudo ntpq -p The ntpq command queries the ntp servers defined and you get with option -p a table back with statistics. 
 
 
 Check with timedatectl , if ntp is enabled and synchronized. If ntp is still not enabled , use: sudo timedatectl set-ntp true sudo systemctl start ntpd Wait a minute and check with timedatectl again. 
 
 
 Addition from user experience 
 From user experience: even with configuring, enabling and starting the ntp daemon the synchronization status was still no (because the time servers configured had an offset). Using 
 sudo systemctl stop ntpd sudo ntpd -gq sudo systemctl start ntpd 
 helped here. The options are for (see also  https://www.tekopolis.com/sync-ntp-immediately-linux/ ) 
 
 
 option -q : overrides the built in sanity check of 1000s. If the system time is over 1000s off from the configured server time, the ntpd process would quit otherwise. 
 
 
 option -q : for quitting the daemon after the clock has been set 
 
 
 How to configure RHEL9 with chrony? 
 Note : In general customer IT is responsible to set up the time synchronization. The information below is just for your convenience, but is not part of GLPT support. 
 Prerequisite:  
 You need a reliable time server.  
 Steps to be checked: 
 
 
 Check if chrony is installed with rpm -q chrony If it is not installed , you can try to install it with sudo yum install chrony 
 
 
 open /etc/chrony.conf with an editor (you need editing permissions or sudo rights) Here you can add the time server with adding the line server hostname iburst Example: server time.google.com iburst 
 
 
 Check if chrony service is enabled / started with systemctl status chronyd If it is not started / enabled 
 
 
 Enable chrony service for being started with a reboot: sudo systemctl enable chronyd 
 
 
 Start chronyd service with sudo systemctl start chronyd 
 
 
 
 
 Check with timedatectl , if chrony is enabled and synchronized.