Managing Serviceguard Eighteenth Edition, September 2010

function customer_defined_run_cmds
{
# ADD customer defined run commands.
: # do nothing instruction, because a function must contain some command.
date >> /tmp/pkg1.datelog
echo 'Starting pkg1' >> /tmp/pkg1.datelog
test_return 51
}
# This function is a place holder for customer defined functions.
# You should define all actions you want to happen here, before the service is
# halted.
function customer_defined_halt_cmds
{
# ADD customer defined halt commands.
: # do nothing instruction, because a function must contain some command.
date >> /tmp/pkg1.datelog
echo 'Halting pkg1' >> /tmp/pkg1.datelog
test_return 52
}
# END OF CUSTOMER DEFINED FUNCTIONS
Adding Serviceguard Commands in Customer Defined Functions
You can add Serviceguard commands (such as cmmodpkg) in the Customer Defined
Functions section of a package control script. These commands must not interact with
the package itself.
If a Serviceguard command interacts with another package, be careful to avoid command
loops. For instance, a command loop might occur under the following circumstances.
Suppose pkg1 does a cmmodpkg -d of pkg2, and pkg2 does a cmmodpkg -d of pkg1.
If both pkg1 and pkg2 start at the same time, pkg1 tries to cmmodpkg pkg2. However,
that cmmodpkg command has to wait for pkg2 startup to complete. pkg2 tries to
cmmodpkg pkg1, but pkg2 has to wait for pkg1 startup to complete, thereby causing
a command loop.
To avoid this situation, it is a good idea to always specify a RUN_SCRIPT_TIMEOUT
and a HALT_SCRIPT_TIMEOUT for all packages, especially packages that use
Serviceguard commands in their control scripts. If a timeout is not specified and your
configuration has a command loop as described above, inconsistent results can occur,
including a hung cluster.
Support for Additional Products
The package control script template provides exits for use with additional products,
including Metrocluster with Continuous Access/XP and EVA, Metrocluster with EMC
SRDF, and the HA NFS toolkit. Refer to the additional product’s documentation for
details about how to create a package using the hooks that are provided in the control
script.
Configuring a Legacy Package 381