HP XC System Software Administration Guide Version 3.1

If something goes wrong and you notice a problem with the clocks synchronizing on any nodes, verify
the internal server's /etc/ntp.conf file and the ntp.conf file on the nodes that are experiencing the
problem.
Other tools, such as ntpq and ntpdc, are also available. For more information, see ntpd(1), ntpq(1), and
ntpdc(1) and the ntp.conf file.
1.8.3 Network Address Translation
The HP XC system uses Network Address Translation (NAT) to enable nodes in the HP XC system without
direct external network connections to open outbound network connections to external addresses. NAT
enables application nodes to access network-available resources without the additional network
management, resources, or load of making application nodes part of an external public network.
1.8.4 Network Information Service
The configuration of Network Information Service (NIS) on an HP XC system is an optional step that is
useful for easing user management and helpful for SLURM and LSF-HPC with SLURM use. You may
decide to set up your user management with some other software, such as Lightweight Directory Access
Protocol (LDAP).
Use either of the following methods for setting up NIS on your HP XC system:
• Set all the nodes as NIS clients. Both the master and slave NIS server are external to the HP XC
system.
• Set the head node as a NIS slave (secondary) server. The NIS master server is external to the HP XC
system. Nodes within the HP XC system use the internal server for NIS information. HP recommends
this configuration for larger systems using NIS.
1.9 Modulefiles
Modulefiles provide a mechanism for accessing software commands and tools, particularly for third-party
software. The HP XC System Software does not use modules for system-level manipulation.
A modulefile contains the information that alters or sets shell environment variables, such as PATH and
MANPATH. Some modulefiles are provided with the HP XC System Software and are available for you to
load. A modulefile must be loaded before it changes the user's environment.
See the HP XC System Software User's Guide for information on creating modulefiles and loading default
modulefiles.
The module command is a shell function that should be defined when users log into the system. It is not
found in the path; you can ensure this function exists by running the following command under the Bourne,
Korn, or bash shells:
$ typeset -f module
The module command features keywords that enable you to load, unload, and list modules, as described
here:
• Use the load keyword to load a module:
# module load package-name
• Use the list keyword to list all loaded modules:
# module list
Be sure to unload a module before loading another to help avoid module versioning conflicts. See
the HP XC System Software User's Guide for additional information.
• Use the avail keyword to list all loaded or unloaded modules:
# module avail
• Use the unload keyword to unload a module:
1.9 Modulefiles 39