Managing Serviceguard Nineteenth Edition, Reprinted June 2011

• Package priority
• auto_run
• failback_policy
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 Event Monitoring Service and its HA monitors can provide monitoring for disks, LAN cards,
and some system events. Refer to the manual Using HA Monitors for more information.
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.
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 in single-node operation, it will leave the single node up
and your applications running. (This is different from the loss of the Serviceguard daemon in a
multi-node cluster, which halts the node with a TOC, and causes packages to be switched to
adoptive nodes.) 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.
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.
Disabling Serviceguard
If for some reason you want to disable Serviceguard on a system, you can do so by commenting
out the following entries in /etc/inetd.conf:
hacl-cfg dgram udp wait root /usr/lbin/cmclconfd cmclconfd -p
hacl-cfg stream tcp nowait root /usr/lbin/cmclconfd cmclconfd -c
Then force inetd to re-read inetd.conf:
/usr/sbin/inetd -c
You can check that this did in fact disable Serviceguard by trying the following command:
cmquerycl -n nodename
where nodename is the name of the local system. If the command fails, you have successfully
disabled Serviceguard.
306 Cluster and Package Maintenance