HP Serviceguard manual Disabling identd, Deleting the Cluster Configuration, Single-Node Operation

Single-Node Operation

Single-node operation occurs in a single-node cluster or in a multi-node cluster, following a situation where all but one node has failed, or where you have shut down all but one node, which will probably have applications running. As long as the Serviceguard daemon cmcld is active, other nodes can rejoin the cluster at a later time.

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 system reset, 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.

However, you should not try to restart Serviceguard, since data corruption might occur if the node were to attempt to start up a new instance of the application that is still running on the node. Instead of restarting the cluster, choose an appropriate time to shutdown and reboot the node, which will allow the applications to shut down and then permit Serviceguard to restart the cluster after rebooting.

Disabling identd

Ignore this section unless you have a particular need to disable identd.

You can configure Serviceguard not to use identd.

CAUTION: This is not recommended. Disabling identd removes an important security layer from Serviceguard. See the white paper Securing Serviceguard at http://www.hp.com/go/ hpux-serviceguard-docs for more information.

If you must disable identd, you can do so by adding the -ioption to the tcp hacl-cfgand hacl-probecommands in /etc/inetd.conf.

For example:

1.Change the cmclconfd entry in /etc/inetd.conf to:

hacl-cfg stream tcp nowait root /usr/lbin/cmclconfd cmclconfd -c -i

2.Change the cmomd entry in /etc/inetd.conf to (all on one line):

hacl-probe stream tcp nowait root /opt/cmom/lbin/cmomd /opt/cmom/lbin/cmomd -i -f /var/opt/cmom/cmomd.log -r /var/opt/cmom

3.Restart inetd:

/etc/init.d/inetd restart

Deleting the Cluster Configuration

As root user, you can delete a cluster configuration from all cluster nodes by using Serviceguard Manager or the command line. The cmdeleteconf command prompts for a verification before deleting the files unless you use the -foption. You can delete the configuration only when the cluster is down. The action removes the binary configuration file from all the nodes in the cluster and resets all cluster-aware volume groups to be no longer cluster-aware.

NOTE: The cmdeleteconf command removes only the cluster binary file /etc/cmcluster/ cmclconfig. It does not remove any other files from the /etc/cmcluster directory.

Although the cluster must be halted, all nodes in the cluster should be powered up and accessible before you use the cmdeleteconf command. If a node is powered down, power it up and boot. If a node is inaccessible, you will see a list of inaccessible nodes together with the following message:

Managing the Running Cluster 225