Managing Serviceguard Fifteenth Edition, reprinted May 2008

Planning and Documenting an HA Cluster
Package Configuration Planning
Chapter 4 181
NOTE This applies only when the packages are automatically started (package
switching enabled); cmrunpkg will never force a package to halt.
Keep in mind that you do not have to set priority, even when one or
more packages depend on another. The default value, no_priority, may
often result in the behavior you want. For example, if pkg1 depends on
pkg2, and priority is set to no_priority for both packages, and other
parameters such as node_name and auto_run are set as recommended in
this section, then pkg1 will normally follow pkg2 to wherever both can
run, and this is the common-sense (and may be the most desirable)
outcome.
The following examples express the rules as they apply to two failover
packages whose failover_policy (see page 292) is configured_node.
Assume pkg1 depends on pkg2, that node1, node2 and node3 are all
specified (in some order) under node_name (see page 288) in the
configuration file for each package, and that failback_policy (see
page 292) is set to automatic for each package.
NOTE Keep the following in mind when reading the examples that follow, and
when actually configuring priorities:
1. auto_run (see page 289) should be set to yes for all the packages
involved; the examples assume that it is.
2. Priorities express a ranking order, so a lower number means a higher
priority (10 is a higher priority than 30, for example).
HP recommends assigning values in increments of 20 so as to leave
gaps in the sequence; otherwise you may have to shuffle all the
existing priorities when assigning priority to a new package.
no_priority, the default, is treated as a lower priority than any
numerical value.
3. All packages with no_priority are by definition of equal priority,
and there is no other way to assign equal priorities; a numerical
priority must be unique within the cluster. See priority (page 293)
for more information.