Managing HP Serviceguard for Linux, Tenth Edition, September 2012

The scripts are also run when the package is validated by cmcheckconf and
cmapplyconf.
A package can make use of both kinds of script, and can launch more than one of each
kind; in that case the scripts will be executed in the order they are listed in the package
configuration file (and in the reverse order when the package shuts down).
Each external script must have three entry points: start, stop, and validate, and
should exit with one of the following values:
• 0 - indicating success.
• 1 - indicating the package will be halted, and should not be restarted, as a result
of failure in this script.
• 2 - indicating the package will be restarted on another node, or halted if no other
node is available.
NOTE: In the case of the validate entry point, exit values 1 and 2 are treated the
same; you can use either to indicate that validation failed.
The script can make use of a standard set of environment variables (including the package
name, SG_PACKAGE, and the name of the local node, SG_NODE) exported by the package
manager or the master control script that runs the package; and can also call a function
to source in a logging function and other utility functions. One of these functions,
sg_source_pkg_env(), provides access to all the parameters configured for this
package, including package-specific environment variables configured via the pev_
parameter (page 223).
NOTE: Some variables, including SG_PACKAGE, and SG_NODE, are available only at
package run and halt time, not when the package is validated. You can use
SG_PACKAGE_NAME at validation time as a substitute for SG_PACKAGE.
For more information, see the template in $SGCONF/examples/
external_script.template.
A sample script follows. It assumes there is another script called monitor.sh, which
will be configured as a Serviceguard service to monitor some application. The
monitor.sh script (not included here) uses a parameter PEV_MONITORING_INTERVAL,
defined in the package configuration file, to periodically poll the application it wants to
monitor; for example:
PEV_MONITORING_INTERVAL 60
At validation time, the sample script makes sure the PEV_MONITORING_INTERVAL and
the monitoring service are configured properly; at start and stop time it prints out the
interval to the log file.
#!/bin/sh
# Source utility functions.
if [[ -z $SG_UTILS ]]
then
148 Planning and Documenting an HA Cluster