Configuring Controllers To Use The Same Local Ntp Servers - HP HPE VAN SDN Controller 2.7 Administrator's Manual

1. Ensure that the Cassandra database is online by entering the following command:
~$ /opt/sdn/cassandra/bin/nodetool status
If you see the following message, the Cassandra database is not online:
Failed to connect to '127.0.0.1:7199': Connection refused
2. If the Cassandra database is not online, you must restart the controller to restart the
Cassandra instance on that controller:
a. Close any instance of the web interface connected to the controller to be restarted.
b. Restart the controller by entering the following command:
~$ sudo service sdnc restart
3. You can perform the repair process while the system, controller, and applications are running.
Enter the following command on each of the controllers to repair and synchronize the
database:
~$ /opt/sdn/cassandra/bin/nodetool repair

Configuring controllers to use the same local NTP servers

Using the same NTP servers for all controllers you plan to include in a team helps to ensure that
the controller clocks remain synchronized. Keeping the system clocks synchronized is especially
important for applications that use the Cassandra database. The controllers in the team must be
configured with one or more NTP servers.
Before you create the controller team, configure all the controllers you plan to include in a team
to use the same local NTP servers.
You can specify an NTP server for each controller using the controller UI (see
server or date and time" (page
Obtain the IP addresses of the local NTP servers for your site. Then ensure that these local NTP
servers are the only NTP servers configured for each controller you plan to include in the team.
1. Log in to the Linux system on which the controller is installed.
2. Verify that NTP is configured on the system by entering the following command:
~$ ntpdc -c peers
If a list of servers is displayed, one or more NTP servers are configured on the system.
3. Edit the /etc/ntp.conf file to remove the entries for servers other than the local NTP
server and replace those entries with an entry for the local NTP server:
a. Remove (or enclose in comments by prepending the # character) all lines that start with
the word server.
b. Add the following line for each local NTP server, where local-ntp-ip is the IP address
of that local NTP server:
server local-ntp-ip iburst
c. Save and close the file.
4. Restart the NTP service by entering the following command:
~$ sudo service ntp restart
5. Verify that the local NTP servers are the only NTP servers configured on the system by
entering the following command:
~$ ntpdc -c peers
NTP is configured correctly if the IP addresses for the local NTP servers are the only entries
displayed.
46)) or using the manual steps below.
Configuring controllers to use the same local NTP servers 103
."Modifying NTP