You must install NTP to properly synchronize services among nodes. We recommend that you configure the controller node to reference more accurate (lower stratum) servers and other nodes to reference the controller node.

# apt-get install ntp # yum install ntp # zypper install ntp By default, the controller node synchronizes the time via a pool of public servers. However, you can optionally edit the /etc/ntp.conf file to configure alternative servers such as those provided by your organization. Edit the /etc/ntp.conf file and add, change, or remove the following keys as necessary for your environment: server NTP_SERVER iburst restrict -4 default kod notrap nomodify restrict -6 default kod notrap nomodify Replace NTP_SERVER with the hostname or IP address of a suitable more accurate (lower stratum) NTP server. The configuration supports multiple server keys. For the restrict keys, you essentially remove the nopeer and noquery options. Remove the /var/lib/ntp/ntp.conf.dhcp file if it exists. Restart the NTP service: # service ntp restart Start the NTP service and configure it to start when the system boots: # systemctl enable ntpd.service # systemctl start ntpd.service

# apt-get install ntp # yum install ntp # zypper install ntp Configure the network and compute nodes to reference the controller node. Edit the /etc/ntp.conf file: Comment out or remove all but one server key and change it to reference the controller node. server controller iburst Remove the /var/lib/ntp/ntp.conf.dhcp file if it exists. Restart the NTP service: # service ntp restart Start the NTP service and configure it to start when the system boots: # systemctl enable ntpd.service # systemctl start ntpd.service

We recommend that you verify NTP synchronization before proceeding further. Some nodes, particularly those that reference the controller node, can take several minutes to synchronize. Run this command on the controller node: # ntpq -c peers remote refid st t when poll reach delay offset jitter ============================================================================== *ntp-server1 192.0.2.11 2 u 169 1024 377 1.901 -0.611 5.483 +ntp-server2 192.0.2.12 2 u 887 1024 377 0.922 -0.246 2.864 Contents in the remote column should indicate the hostname or IP address of one or more NTP servers. Contents in the refid column typically reference IP addresses of upstream servers. Run this command on the controller node: # ntpq -c assoc ind assid status conf reach auth condition last_event cnt =========================================================== 1 20487 961a yes yes none sys.peer sys_peer 1 2 20488 941a yes yes none candidate sys_peer 1 Contents in the condition column should indicate sys.peer for at least one server. Run this command on all other nodes: # ntpq -c peers remote refid st t when poll reach delay offset jitter ============================================================================== *controller 192.0.2.21 3 u 47 64 37 0.308 -0.251 0.079 Contents in the remote column should indicate the hostname of the controller node. Contents in the refid column typically reference IP addresses of upstream servers. Run this command on all other nodes: # ntpq -c assoc ind assid status conf reach auth condition last_event cnt =========================================================== 1 21181 963a yes yes none sys.peer sys_peer 3 Contents in the condition column should indicate sys.peer.