Managing HP Serviceguard A.11.20.20 for Linux, May 2013

7.8.8.1 Changes that Will Trigger Warnings
Changes to the following will trigger warnings, giving you a chance to cancel, if the change would
cause the package to fail.
NOTE: You will not be able to cancel if you use cmapplyconf -f.
• Package nodes
• Package dependencies
• Package weights (and also node capacity, defined in the cluster configuration file)
• Package priority
• auto_run
• failback_policy
7.9 Responding to Cluster Events
Serviceguard does not require much ongoing system administration intervention. As long as there
are no failures, your cluster will be monitored and protected. In the event of a failure, those packages
that you have designated to be transferred to another node will be transferred automatically. Your
ongoing responsibility as the system administrator will be to monitor the cluster and determine if
a transfer of package has occurred. If a transfer has occurred, you have to determine the cause
and take corrective actions.
The typical corrective actions to take in the event of a transfer of package include:
• Determining when a transfer has occurred.
• Determining the cause of a transfer.
• Repairing any hardware failures.
• Correcting any software problems.
• Restarting nodes.
• Transferring packages back to their original nodes.
• Enabling package switching.
7.10 Single-Node Operation
In a multi-node cluster, you could have a situation in which all but one node has failed, or you
have shut down all but one node, leaving your cluster in single-node operation. This remaining
node will probably have applications running on it. As long as the Serviceguard daemon cmcld
is active, other nodes can rejoin the cluster.
If the Serviceguard daemon fails when the cluster is in single-node operation, it will leave the single
node up and your applications running
NOTE: This means that Serviceguard itself is no longer running.
It is not necessary to halt the single node in this scenario, since the application is still running, and
no other node is currently available for package switching. (This is different from the loss of the
Serviceguard daemon in a multi-node cluster, which halts the node (system reset), and causes
packages to be switched to adoptive nodes.)
You should not try to restart Serviceguard, since data corruption might occur if another node were
to attempt to start up a new instance of the application that is still running on the single node.
Instead of restarting the cluster, choose an appropriate time to shut down the applications and
reboot the node; this will allow Serviceguard to restart the cluster after the reboot.
7.9 Responding to Cluster Events 247