HP Serviceguard A.11.20- Managing Serviceguard Twentieth Edition, August 2011

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.
NOTE: You should not disable Serviceguard on a system on which it is actually running. If you
are not sure, you can get an indication by means of the command:
ps -e | grep cmclconfd
If there are cmclconfd processes running, it does not mean for certain that Serviceguard is running
on this system (cmclconfd could simply be handling UDP queries from a Serviceguard cluster on
the same subnet) but it does mean you should investigate further before disabling Serviceguard.
Removing Serviceguard from a System
To remove Serviceguard from a node, use the swremove command.
CAUTION: Remove the node from the cluster first. If you run the swremove command on a server
that is still a member of a cluster, it will cause that cluster to halt, and the cluster configuration to
be deleted.
To remove Serviceguard:
1. If the node is an active member of a cluster, halt the node.
2. If the node is included in a cluster configuration, remove the node from the configuration.
3. If you are removing Serviceguard from more than one node, issue swremove on one node
at a time.
320 Cluster and Package Maintenance