Managing HP Serviceguard for Linux Ninth Edition, April 2009

• dependency_location must be either same_node or all_nodes, and must be the
same for both packages.
• Both packages must be failover packages whose failover_policy (page 201) is
configured_node.
Rules for different_node and any_node Dependencies
These rules apply to packages whose dependency_condition is UP and whose
dependency_location is different_node or any_node. For same-node dependencies,
see Simple Dependencies (page 121); for exclusionary dependencies, see “Rules for
Exclusionary Dependencies” (page 127).
• Both packages must be failover packages whose failover_policy (page 201) is
configured_node.
• The priority (page 201) of the package depended on must be higher than or equal
to the priority of the dependent package and the priorities of that package's
dependents.
— For example, if pkg1 has a different_node or any_node dependency on
pkg2, pkg2's priority must be higher than or equal to pkg1's priority and the
priority of any package that depends on pkg1 to be UP. pkg2's node order
dominates when Serviceguard is placing the packages.
• A package cannot depend on itself, directly or indirectly.
For example, not only must pkg1 not specify itself in the dependency_condition
(page 202), but pkg1 must not specify a dependency on pkg2 if pkg2 depends on
pkg1, or if pkg2 depends on pkg3 which depends on pkg1, etc.
• “Dragging” rules apply. See “Dragging Rules for Simple Dependencies” (page 123).
About Package Weights
Package weights and node capacities allow you to restrict the number of packages that
can run concurrently on a given node, or, alternatively, to limit the total package
“weight” (in terms of resource consumption) that a node can bear.
For example, suppose you have a two-node cluster consisting of a large system and a
smaller system. You want all your packages to be able to run on the large system at
the same time, but, if the large node fails, you want only the critical packages to run
on the smaller system. Package weights allow you to configure Serviceguard to enforce
this behavior.
Package Weights and Node Capacities
You define a capacity, or capacities, for a node (in the cluster configuration file), and
corresponding weights for packages (in the package configuration file).
Node capacity is consumed by package weights. Serviceguard ensures that the capacity
limit you set for a node is never exceeded by the combined weight of packages running
128 Planning and Documenting an HA Cluster