Managing HP Serviceguard for Linux Ninth Edition, April 2009

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 257)); for modular packages, put the code in the
package’s external script (see “About External Scripts” (page 137)).
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).
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.
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 32). In this context, you can
configure packages to fail over from a node on one subnet to a node on another.
Package Configuration Planning 141