HP XC System Software Administration Guide Version 2.1

7.2.2 Using File Overrides to the Golden Image
File overrides overwrite files delivered in the golden image. File overrides are copied to the
client nodes after the golden image is transferred, thus overriding files in the golden image itself.
File overrides are organized in a subdirectory hierarchy rooted at /var/lib/systemim-
ager/overrides. Each subdirectory of the ./overrides directory specifies a complete
file override hierarchy that is copied to the root directory of the client’s file system.
The necessity to use file overrides is specified in the master autoinstall scripts located
at /var/lib/systemimager/scripts. Each master autoinstall script contains
an OVERRIDES variable specifying o ne or more overrides s ubd irectories to assoc iate
with this m aster autoinstall script. To specify a select number of nodes to receive a
particular override, make a copy of the appropriate master autoinstall script, and modify
the OVERRIDES variable to match your overrides subdirectory name. Finally, in the
/var/lib/systemimager/scripts directory, create symbolic links to this master
autoinstall script for the nodes that will receive this override. The symbolic link names must
follow the format name.sh,wherename is the hostname of each node to receive the o verride.
For further information on using overrides in the systemimager environment, see the FAQ
chapter in the SystemImager Manual located at http://systemimager.org/doc.
7.2.3 Using Per-Node Service Configuration
The HP XC system c onf ig uration pro cess uses per- node configuration script s to ach ieve
personalized role configurations as necessary on each node. The per-node configuration process
occurs initially during HP X C system configuration, at the tim e each client node is autoinstalled.
The HP XC configuration and m anag emen t database (cmdb) contains th e per-node role an d
service configuration, and is queried on each node’s initial boot to identify which roles and
services to configure; see Section 3.5 for more information. A per-node configuration script
is associated with each configurable service, and is executed o n the client node if the cmdb
identifies this client as hosting this service.
The per-node configuration process actually occu rs in two p hases:
Global Service Configuration
The global configuration pha se is intended to set up the per-node co nfigu ration phase by
globally configuring the service for use within the HP XC sy stem. The global configuration
of a service is accomplished by executing a global configuration script (a gconfig script)
during the ru nning of the cluster_config u tility. It is here that interactio n with the
administrator proceeds as necessary to configure the service. In order to configure a new
service into the HP XC system using gconfig, you must run the cluster_config
utility a gain.
The global service configuration script has three locations where i nform a tion can be stored:
cmdb
The database should be the target for node-specific configuration data, that is,
services that are not ubi qui tous in the HP XC system, but will only run o n one or a
handful of nodes.
Golden client file system
By writing to the golden cl ient file system, the script is able to add or modif y files
that are propagated to all nodes of the HP XC system b y using the go lden image.
This is useful for configuring services that are ubiquitous in the HP XC system.
Cluster c
ommon storage (/hptc_cluster)
By writin g to the cluster common storage, the script is able to add or modify files
that are visible to all the no des of the cluster. This method may be used for either
per-node or cluster-ubiquitou s services.
Distributing Software Throughout the System 7-3