Managing HP Serviceguard for Linux, Tenth Edition, September 2012

Cluster SNMP Agent Daemon: cmsnmpd
This daemon collaborates with the SNMP Master Agent to provide instrumentation for
the cluster Management Information Base (MIB).
The SNMP Master Agent and the cmsnmpd provide notification (traps) for cluster-related
events. For example, a trap is sent when the cluster configuration changes, or when a
Serviceguard package has failed. To configure the agent to send traps to one or more
specific destinations, add the trap destinations to /etc/snmp/snmptrapd.conf (SUSE
and Red Hat). Make sure traps are turned on with trap2sink in /etc/snmp/
snmpd.conf (SUSE and Red Hat).
The installation of the cmsnmpd rpm configures snmpd and cmsnmpd to start up
automatically. Their startup scripts are in /etc/init.d/. The scripts can be run manually
to start and stop the daemons.
For more information, see the cmsnmpd (1)manpage.
Cluster WBEM Agent Daemon: cmwbemd
This daemon collaborates with the Serviceguard WBEM provider plug-in module
(SGProviders) and WBEM services cimserver to provide notification (WBEM Indications)
of Serviceguard cluster events to Serviceguard WBEM Indication subscribers that have
registered a subscription with the cimserver. For example, an Indication is sent when
the cluster configuration changes, or when a Serviceguard package has failed.
You can start and stop cmwbemd with the commands /sbin/init.d/cmwbemagt
start and /sbin/init.d/cmwbemagt stop.
Proxy Daemon: cmproxyd
This daemon is used to proxy or cache Serviceguard configuration data for use by certain
Serviceguard commands running on the local node. This allows these commands to get
the data quicker and removes the burden of responding to certain requests from cmcld.
How the Cluster Manager Works
The cluster manager is used to initialize a cluster, to monitor the health of the cluster, to
recognize node failure if it should occur, and to regulate the re-formation of the cluster
when a node joins or leaves the cluster. The cluster manager operates as a daemon
process that runs on each node. During cluster startup and re-formation activities, one
node is selected to act as the cluster coordinator. Although all nodes perform some cluster
management functions, the cluster coordinator is the central point for inter-node
communication.
Configuration of the Cluster
The system administrator sets up cluster configuration parameters and does an initial
cluster startup; thereafter, the cluster regulates itself without manual intervention in normal
operation. Configuration parameters for the cluster include the cluster name and nodes,
How the Cluster Manager Works 37