Managing HP Serviceguard for Linux, Tenth Edition, September 2012

package halts and cannot restart because none of the nodes on its node_list is
available.
Serviceguard provides two ways to do this: you can use the preview mode of Serviceguard
commands, or you can use the cmeval (1m) command to simulate different cluster
states.
Alternatively, you might want to model changes to the cluster as a whole; cmeval allows
you to do this; see “Using cmeval” (page 263).
What You Can Preview
You can preview any of the following, or all of them simultaneously:
• Cluster bring-up (cmruncl)
• Cluster node state changes (cmrunnode, cmhaltnode)
• Package state changes (cmrunpkg, cmhaltpkg)
• Package movement from one node to another
• Package switching changes (cmmodpkg -e)
• Availability of package subnets, resources, and storage
• Changes in package priority, node order, dependency, failover and failback policy,
node capacity and package weight
Using Preview mode for Commands and in Serviceguard Manager
The following commands support the -t option, which allows you to run the command
in preview mode:
• cmhaltnode [–t] [–f] <node_name>
• cmrunnode [–t] <node_name>
• cmhaltpkg [–t] <package_name>
• cmrunpkg [–t] [-n node_name] <package_name>
• cmmodpkg { -e [-t] | -d } [-n node_name] <package_name>
• cmruncl –v [–t]
NOTE: You cannot use the -t option with any command operating on a package in
maintenance mode; see “Maintaining a Package: Maintenance Mode” (page 255).
For more information about these commands, see their respective manpages. You can
also perform these preview functions in Serviceguard Manager: check the Preview
[...] box for the action in question.
When you use the -t option, the command, rather than executing as usual, predicts the
results that would occur, sending a summary to $stdout. For example, assume that
pkg1 is a high-priority package whose primary node is node1, and which depends on
262 Cluster and Package Maintenance