Managing Serviceguard Nineteenth Edition, Reprinted June 2011

NOTE: For design and configuration information about clusters which span subnets, including
site-aware disaster-tolerant clusters, see the documents listed under “Cross-Subnet Configurations”
(page 29).
Figure 15 After Package Switching
Failover Policy
The Package Manager selects a node for a failover package to run on based on the priority list
included in the package configuration file together with the failover_policy parameter, also
in the configuration file. The failover policy governs how the package manager selects which node
to run a package on when a specific node has not been identified and the package needs to be
started. This applies not only to failovers but also to startup for the package, including the initial
startup. The failover policies are configured_node (the default), min_package_node,
site_preferred and site_preferred_manual. The parameter is set in the package
configuration file. See “failover_policy” (page 226) for more information.
Package placement is also affected by package dependencies and weights, if you choose to use
them. See “About Package Dependencies” (page 128) and “About Package Weights” (page 135).
Automatic Rotating Standby
Using the min_package_node failover policy, it is possible to configure a cluster that lets you
use one node as an automatic rotating standby node for the cluster. Consider the following package
configuration for a four node cluster. Note that all packages can run on all nodes and have the
same node_name lists. Although the example shows the node names in a different order for each
package, this is not required.
Table 2 Package Configuration Data
FAILOVER_POLICYNODE_NAME ListPackage Name
MIN_PACKAGE_NODEnode1, node2, node3, node4pkgA
MIN_PACKAGE_NODEnode2, node3, node4, node1pkgB
MIN_PACKAGE_NODEnode3, node4, node1, node2pkgC
How the Package Manager Works 51