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Sun Cluster Software Installation Guide for Solaris OS

How to Configure Network Time Protocol (NTP)

Perform this task to create or modify the NTP configuration file after you install Sun Cluster software. You must also modify the NTP configuration file when you add a node to an existing cluster or when you change the private hostname of a node in the cluster.

The primary requirement when you configure NTP, or any time synchronization facility within the cluster, is that all cluster nodes must be synchronized to the same time. Consider accuracy of time on individual nodes to be of secondary importance to the synchronization of time among nodes. You are free to configure NTP as best meets your individual needs if this basic requirement for synchronization is met.

See the Sun Cluster Concepts Guide for Solaris OS for further information about cluster time. See the /etc/inet/ntp.cluster template file for additional guidelines on how to configure NTP for a Sun Cluster configuration.

  1. Did you install your own /etc/inet/ntp.conf file before you installed Sun Cluster software?

    • If yes, you do not need to modify your ntp.conf file. Skip to Step 8.

    • If no, proceed to Step 2.

  2. Become superuser on a cluster node.

  3. Do you have your own /etc/inet/ntp.conf file to install on the cluster nodes?

    • If no, proceed to Step 4.

    • If yes, copy your /etc/inet/ntp.conf file to each node of the cluster, then skip to Step 6.

  4. On one node of the cluster, edit the private hostnames in the /etc/inet/ntp.conf.cluster file.

    Note –

    Do not rename the ntp.conf.cluster file as ntp.conf.

    If the /etc/inet/ntp.conf.cluster file does not exist on the node, you might have an /etc/inet/ntp.conf file from an earlier installation of Sun Cluster software. Sun Cluster software creates the /etc/inet/ntp.conf.cluster file as the NTP configuration file if an /etc/inet/ntp.conf file is not already present on the node. If so, perform the following edits instead on that ntp.conf file.

    1. Ensure that an entry exists for the private hostname of each cluster node.

      If you changed any node's private hostname, ensure that the NTP configuration file contains the new private hostname.

    2. Remove any unused private hostnames.

      The ntp.conf.cluster file might contain nonexistent private hostnames. When a node is rebooted, the system generates error messages as the node attempts to contact those nonexistent private hostnames.

    3. If necessary, make other modifications to meet your NTP requirements.

  5. Copy the NTP configuration file to all nodes in the cluster.

    The contents of the NTP configuration file must be identical on all cluster nodes.

  6. Stop the NTP daemon on each node.

    Wait for the stop command to complete successfully on each node before you proceed to Step 7.


    # /etc/init.d/xntpd stop

  7. Restart the NTP daemon on each node.

    • If you use the ntp.conf.cluster file, run the following command:


      # /etc/init.d/xntpd.cluster start

      The xntpd.cluster startup script first looks for the /etc/inet/ntp.conf file. If that file exists, the script exits immediately without starting the NTP daemon. If the ntp.conf file does not exist but the ntp.conf.cluster file does exist, the script starts the NTP daemon. In this case, the script uses the ntp.conf.cluster file as the NTP configuration file.

    • If you use the ntp.conf file, run the following command:


      # /etc/init.d/xntpd start

  8. Are you using Sun Cluster on a SPARC based system and you intend to use Sun Management Center to monitor the cluster?