Managing Serviceguard Eighteenth Edition, September 2010

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. You must edit /etc/SnmpAgent.d/
snmpd.conf to tell cmsnmpd where to send this information.
You must also edit /etc/rc.config.d/cmsnmpagt to auto-start cmsnmpd. Configure
cmsnmpd to start before the Serviceguard cluster comes up.
For more information, see the cmsnmpd (1m) manpage.
Service Assistant Daemon: cmserviced
This daemon forks and execs any scripts or processes required by the cluster daemon,
cmcld. There are two type of forks that this daemon carries out:
Executing package run and halt scripts
Launching services
For services, cmcld monitors the service process and, depending on the number of
service retries, cmcld either restarts the service through cmserviced or it causes the
package to halt and moves the package to an available alternate node.
Quorum Server Daemon: qs
Using a Quorum Server is one way to break a tie and establish a quorum when the
cluster is re-forming; the other way is to use a cluster lock. See “Cluster Quorum to
Prevent Split-Brain Syndrome” and “Cluster Lock ” (page 62).
The Quorum Server, if used, runs on a system external to the cluster and is started by
the system administrator, not by Serviceguard. It is normally started from /etc/
inittab with the respawn option, which means that it automatically restarts if it
fails or is killed. All members of the cluster initiate and maintain a connection to the
Quorum Server; if it dies, the Serviceguard nodes will detect this and then periodically
try to reconnect to it. If there is a cluster re-formation while the Quorum Server is down
and tie-breaking is needed, the re-formation will fail and all the nodes will halt (system
reset). For this reason it is important to bring the Quorum Server back up as soon as
possible.
For more information about the Quorum Server software and how it works, see the
latest version of the HP Serviceguard Quorum Server release notes at www.hp.com/go/
hpux-serviceguard-docs -> HP Serviceguard Quorum Server Software.
Network Manager Daemon: cmnetd
This daemon monitors the health of cluster networks, and performs local LAN failover.
It also handles the addition and deletion of relocatable package IP addresses for both
IPv4 and IPv6.
Serviceguard Architecture 57