openstack-manuals/doc/install-guide/source/environment-ntp-controller.rst

Controller node

Perform these steps on the controller node.

Install and configure components

1. Install the packages:

   For Ubuntu:

   # apt install chrony

   For RHEL or CentOS:

   # yum install chrony

   For SUSE:

   # zypper install chrony

2. Edit the chrony.conf file and add, change, or remove the following keys as necessary for your environment.

   For RHEL, CentOS, or SUSE, edit the /etc/chrony.conf file:

   server NTP_SERVER iburst

   For Ubuntu, edit the /etc/chrony/chrony.conf file:

   server NTP_SERVER iburst

   Replace NTP_SERVER with the hostname or IP address of a suitable more accurate (lower stratum) NTP server. The configuration supports multiple server keys.

   Note

   By default, the controller node synchronizes the time via a pool of public servers. However, you can optionally configure alternative servers such as those provided by your organization.

3. To enable other nodes to connect to the chrony daemon on the controller node, add this key to the same chrony.conf file mentioned above:

   allow 10.0.0.0/24

   If necessary, replace 10.0.0.0/24 with a description of your subnet.

4. Restart the NTP service:

   For Ubuntu:

   # service chrony restart

   For RHEL, CentOS, or SUSE:

   # systemctl enable chronyd.service
   # systemctl start chronyd.service