HP-UX SNAplus2 R7 Administration Guide

Appendix DUsing SNAplus2 in a High Availability Environment
Table D–2 Suggestions for Defining the SNAplus2 Package
Item Suggestion
Package Name Use a name that identifies how the SNAplus2 package
is being used. For example, sna.
Service Name Use the name of the SNAplus2 LS that you are
making highly available. For example, HALS.
Service Command This command will be used to monitor the SNAplus2
LS. Use the snapmon command which has been
designed for this purpose. For example, /opt/sna/
bin/snapmon HALS. See Section D.3.4,
Specifying
the Service Command below for more information.
Package Control Script Location This is the location of the script to start and stop the
SNAplus2 package on a server. For example, /etc/
cmcluster/sna/sna.cntl. See Section D.3.6,
Customizing the SNAplus2 Package Control Script
below for more information.
IP Address An IP Address must be associated with the SNAplus2
package if you are using an IP based network for SNA
network connectivity. See Section D.3.5, Specifying a
Package IP Address for more information.
D.3.4 Specifying the Service Command
The Service Command starts a Service, which is an HP-UX process that ServiceGuard monitors. The termination
of the process indicates to ServiceGuard that the package has failed, and that the package needs to be migrated to
another system. The Service can be the main process that makes up the package, but for SNAplus2 it is a process
that monitors whether the SNAplus2 software is providing SNA network connectivity. The best way to determine
if an SNAplus2 server is providing SNA network connectivity is to check the status of each SNAplus2 LS that the
server uses.
One way to check the status of an SNAplus2 LS is with the snapadmin start_ls command. For example,
snapadmin start_ls, ls_name=HALS
LS details are:
Activation state = active
Port name = HAPORT
In this example, the state of the LS is active, which means the server is currently providing SNA network connectivity
to a remote SNA system. The snapadmin start_ls command is not useful as a Service Command, however,
because the command returns after displaying the state information. If snapadmin start_ls were used as a
Service Command, ServiceGuard would interpret the termination of the snapadmin start_ls process as an
indication that the SNAplus2 package had failed. For this reason, the snapmon utility has been provided for use
as a Service command in an SNAplus2 package.
The snapmon utility continuously monitors the state of an SNAplus2 LS by querying SNAplus2 to determine if it
is active. If the LS is ever reported to be in a state other than active, the program terminates. The only exception
is during initialization, when certain errors can be ignored.
Usage:
snapmon [-i interval] [-r retry_count] conname
conname
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