Notes That Apply Before You Invoke the cluster_config Utility

Remove the management_hub and console_network Roles From the Head Node on Systems With More Than 256 Nodes

By default, the head node is assigned with the console_network and management_hub roles. You have the flexibility to assign the console_network and management_hub roles to multiple nodes and HP recommends that you consider using one management hub for every 64 to 128 nodes.

However, on systems with more than 256 nodes, HP recommends that you remove the console_network and management_hub roles from the head node so that the management hub activity does not interfere with the services that only run on the head node.

Use the cluster_config utility to assign roles or remove roles from a node or nodes.

Follow Role Assignment Guidelines for Improved Availability

When you are configuring services for improved availability, follow the role assignment guidelines in Table 1-2 in the HP XC System Software Installation Guide. Role assignments for a traditional HP XC system without improved availability of services is slightly different, thus it is important to follow the guidelines in Table 1-2.

Update initrd Files With Required Hardware

When client nodes contain additional hardware that is required for booting (such as SCSI controllers) and the hardware is not present on the head node, you must modify the initrd file on the head node to include the drivers. Perform this task before the cluster_config utility is run for the first time. Performing this task after running the cluster_config utility requires you to remove the golden image.

For example, if a client node contains the Adaptec SCSI controller, the following script updates all initrd files:

#!/bin/bash

FILES=`find /boot -name initrd\* -print`

for i in $FILES
do
    VERSION=`echo $i | sed -e 's/^.*initrd-\(.*\).img/\1/'`
    if [ ! -z "$VERSION" ]
    then
        NEWF=/tmp/initrd-$VERSION.img
        echo "/sbin/mkinitrd --with=aacraid -f $NEWF $VERSION"
        /sbin/mkinitrd --with=aacraid -f $NEWF $VERSION
        if [ -f $NEWF ]
        then
            echo "replacing $i with $NEWF"
            rm $i
            mv $NEWF $i
        fi
    fi
done

Change the InfiniBand Switch Root Password

The InfiniBand switches run Linux and have a root password. Occasionally, you might have to log into the InfiniBand switch as root, so HP recommends that you use the following procedure to change the default root password on the InfiniBand switches:

Save the Contents of the /etc/dhcpd.conf File

This note applies only to systems using a Myrinet® interconnect. Skip this task if the system uses another interconnect type.

An Appendix in the HP XC System Software Installation Guide instructs you to configure the interconnect switch line monitoring cards before the system is configured. Part of the procedure involves adding entries to the /etc/dhcpd.conf file.

The cluster_config utility rewrites the /etc/dhcpd.conf file, and if you edit this file before invoking the utility, your changes to this file are lost.

Therefore, save your customizations to the /etc/dhcpd.conf file before invoking the cluster_config utility:

# cp /etc/dhcpd.conf /etc/dhcpd.conf.ORIG

Error Messages for InfiniBand Switch Entries

If the InfiniBand switch entries in the /etc/hosts file contain a trailing space, the cluster_config utility displays a message similar to the following for each switch:

Executing C52xcgraph gconfigure
sh: line 1: /PortCounters.csv: No such file or directory
Found no adapter info on IR0N00

Failed to find any Infiniband ports

To work around this issue, use the text editor of your choice to edit the /etc/hosts file and remove the trailing spaces on the IRxNxx lines