Configuring NTP clients

(Hyper-V only) This procedure configures delegates to synchronize their clocks with the NTP server on the Control Center master host. Perform this procedure only if the delegates do not have internet access. Repeat this procedure on each delegate in your Control Center cluster.

  1. Gain access to the Control Center host, through the console interface of your hypervisor, or through a remote shell utility such as PuTTY.
  2. Start a command-line session as root as follows:
    1. In the Appliance Administration menu, select Root Shell.
    2. Select Run, and then press Enter.
    The menu is replaced by a command prompt similar to the following example:
    [root@hostname ~]#
  3. Create a backup of the NTP configuration file.
    cp -p /etc/ntp.conf /etc/ntp.conf.orig
  4. Edit the NTP configuration file as follows:
    1. Open /etc/ntp.conf with a text editor.
    2. Replace all lines in the file with the following lines:
      # Point to the master time server
      server MASTER_ADDRESS
      
      restrict default ignore
      restrict 127.0.0.1
      restrict MASTER_ADDRESS mask 255.255.255.255 nomodify notrap noquery
      
      driftfile /var/lib/ntp/drift
    3. Replace both instances of MASTER_ADDRESS with the IPv4 address of the host where the NTP server is running (the Control Center master host).
    4. Save the file and exit the editor.
  5. Stop Control Center.
    systemctl stop serviced
  6. Synchronize the clock with the master server.
    ntpd -gq
  7. Enable and start the NTP daemon as follows:
    1. Enable the ntpd daemon.
      systemctl enable ntpd
    2. Configure ntpd to start when the system starts.
      Currently, an unresolved issue associated with NTP prevents ntpd from restarting correctly after a reboot, and the following commands provide a workaround to ensure that it does.
      echo "systemctl start ntpd" >> /etc/rc.d/rc.local
      chmod +x /etc/rc.d/rc.local
    3. Start ntpd.
      systemctl start ntpd
  8. Start Control Center.
    systemctl start serviced