Managing HP Serviceguard A.11.20.10 for Linux, December 2012

4.8.11.2 Determining Why a Package Has Shut Down
You can use an external script (or CUSTOMER DEFINED FUNCTIONS area of a legacy package
control script) to find out why a package has shut down.
Serviceguard sets the environment variable SG_HALT_REASON in the package control script to
one of the following values when the package halts:
• failure - set if the package halts because of the failure of a subnet, resource, or service it
depends on
• user_halt - set if the package is halted by a cmhaltpkg or cmhaltnode command, or
by corresponding actions in Serviceguard Manager
• automatic_halt - set if the package is failed over automatically because of the failure of
a package it depends on, or is failed back to its primary node automatically
(failback_policy = automatic)
You can add custom code to the package to interrogate this variable, determine why the package
halted, and take appropriate action. For legacy packages, put the code in the
customer_defined_halt_cmds() function in the CUSTOMER DEFINED FUNCTIONS area
of the package control script (see “Adding Customer Defined Functions to the Package Control
Script ” (page 228)); for modular packages, put the code in the package’s external script (see
“About External Scripts” (page 122)).
For example, if a database package is being halted by an administrator (SG_HALT_REASON set
to user_halt) you would probably want the custom code to perform an orderly shutdown of the
database; on the other hand, a forced shutdown might be needed if SG_HALT_REASON is set to
failure, indicating thatthe package is halting abnormally (for example, because of the
failure of a service it depends on).
4.8.11.2.1 last_halt_failed Flag
cmviewcl -v -f line displays a last_halt_failed flag.
NOTE: last_halt_failed appears only in the line output of cmviewcl, not the default
tabular format; you must use the -f line option to see it.
The value of last_halt_failed is no if the halt script ran successfully, or has not run since the
node joined the cluster, or has not run since the package was configured to run on the node;
otherwise it is yes.
4.8.12 About Cross-Subnet Failover
It is possible to configure a cluster that spans subnets joined by a router, with some nodes using
one subnet and some another. This is known as a cross-subnet configuration; see “Cross-Subnet
Configurations” (page 27). In this context, you can configure packages to fail over from a node
on one subnet to a node on another.
The implications for configuring a package for cross-subnet failover are as follows:
• For modular packages, you must configure two new parameters in the package configuration
file to allow packages to fail over across subnets:
◦ ip_subnet_node (page 177) - to indicate which nodes a subnet is configured on
◦ monitored_subnet_access (page 176) - to indicate whether a monitored subnet is
configured on all nodes ( FULL) or only some (PARTIAL). (Leaving
4.8 Package Configuration Planning 125