Configuring an NTP master server

Use this procedure to configure an NTP master server on the Control Center master host. Perform this procedure only if the host does not have internet access.

  1. Log in to the Control Center master host as root, or as a user with superuser privileges.
  2. Create a backup of the NTP configuration file.
    cp -p /etc/ntp.conf /etc/ntp.conf.orig
  3. Edit the NTP configuration file.
    1. Open /etc/ntp.conf with a text editor.
    2. Replace all of the lines in the file with the following lines:
      # Use the local clock
      server prefer
      fudge stratum 10
      driftfile /var/lib/ntp/drift
      broadcastdelay 0.008
      # Give localhost full access rights
      # Grant access to client hosts
      restrict Address-Range mask Netmask nomodify notrap
    3. Replace Address-Range with the range of IPv4 network addresses that are allowed to query this NTP server.
      For example, the following IP addresses are assigned to Control Center hosts:

      For the preceding addresses, the value for Address-Range is

    4. Replace Netmask with the IPv4 network mask that corresponds with the address range.
      For example, a valid network mask for is
    5. Save the file and exit the editor.
  4. Stop Control Center.
    systemctl stop serviced
  5. Enable and start the NTP daemon.
    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
  6. Start Control Center.
    systemctl start serviced