Managing Serviceguard 13th Edition, February 2007

Understanding Serviceguard Software Components
How the Package Manager Works
Chapter 3 77
restart the package on a new node in response to a failure. Once the
cluster is running, the package switching attribute of each package can
be temporarily set with the cmmodpkg command; at reboot, the
configured value will be restored.
The parameter is coded in the package ASCII configuration file:
# The default for AUTO_RUN is YES. In the event of a
# failure, this permits the cluster software to transfer the
package to an adoptive node. Adjust as necessary.
AUTO_RUN YES
A package switch involves moving failover packages and their associated
IP addresses to a new system. The new system must already have the
same subnet configured and working properly, otherwise the packages
will not be started.
When a package fails over, TCP connections are lost. TCP applications
must reconnect to regain connectivity; this is not handled automatically.
Note that if the package is dependent on multiple subnets, all of them
must be available on the target node before the package will be started.
If the package has a dependency on a resource or another package, the
dependency must be met on the target node before the package can start.
The switching of relocatable IP addresses is shown in Figure 3-5 and
Figure 3-6. Figure 3-5 shows a two node cluster in its original state with
Package 1 running on Node 1 and Package 2 running on Node 2. Users
connect to node with the IP address of the package they wish to use.
Each node has a stationary IP address associated with it, and each
package has an IP address associated with it.