Managing Serviceguard Eighteenth Edition, September 2010

services also are used for other types of inter-node communication. (The heartbeat is
explained in more detail in the chapter “Understanding Serviceguard Software.”)
Failover
Any host system running in a Serviceguard cluster is called an active node. Under
normal conditions, a fully operating Serviceguard cluster monitors the health of the
cluster's components on all its active nodes.
Most Serviceguard packages are failover packages. When you configure a failover
package, you specify which active node will be the primary node where the package
will start, and one or more other nodes, called adoptive nodes, that can also run the
package.
Figure 1-2 shows what happens in a failover situation.
Figure 1-2 Typical Cluster After Failover
After this transfer, the failover package typically remains on the adoptive node as long
the adoptive node continues running. If you wish, however, you can configure the
package to return to its primary node as soon as the primary node comes back online.
Alternatively, you may manually transfer control of the package back to the primary
node at the appropriate time.
Figure 1-2 does not show the power connections to the cluster, but these are important
as well. In order to remove all single points of failure from the cluster, you should
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