HP UX SNAplus2 Customizing the SNAplus2 Package Control, Script, Modifying the Path variable

Using SNAplus2 in a High Availability Environment

Using SNAplus2 with MC/ServiceGuard

	Customizing the SNAplus2 Package Control
	Script
	The last step in defining an SNAplus2 package is customizing the
	Package Control Script to instruct ServiceGuard how to start and stop
	the SNAplus2 software associated with the package. The example file
	that we used in our list of suggestions is
	/etc/cmcluster/sna/sna.cntl. See Table D-2, “Suggestions for
	Defining the SNAplus2 Package.” To customize the Package Control
	Script, you must use an editor like vi. Package Control Script
	customization cannot be done using SAM.
	Modifying the PATH variable
	Since the run and halt commands will use SNAplus2 executable
	programs, you must add the SNAplus2 executable directory to the PATH
	variable in the Package Control Script. Add the directory
	/opt/sna/bin to the PATH variable.
	Adding Customer Defined Functions
	To finish the SNAplus2 package definition, add commands to start and
	stop the SNAplus2 package to the Package Control Script. The
	commands you will use depend on your specific SNA network
	configuration. If possible, design the run and halt commands to migrate
	the SNAplus2 package to another server transparently; that is, without
	impacting the applications. For the best level of application
	transparency, we recommend that you use a client/server configuration,
	and that you configure ServiceGuard to activate the same SNAplus2
	node, port, and LS on the backup server that is configured to run on the
	primary server. This way, the SNAplus2 applications can access the same
	set of LUs whether the SNA network connectivity is being provided by
	the primary server or the backup server.
	We recommend that you use a client/server configuration in high
NOTE
	availability environments.
	The run and halt commands must be designed to allow ServiceGuard to
	migrate the SNAplus2 package from the primary server to the backup
	server. If the SNAplus2 package fails on the primary server (which is
	indicated by the termination of the snapmon process), ServiceGuard
	will invoke the halt commands on the primary server. Most often the
	command, snap stop, is sufficient because that command will halt all of

376 Appendix D