Managing Serviceguard 13th Edition, February 2007

Understanding Serviceguard Software Components
Serviceguard Architecture
Chapter 362
Clients send queries to the object manager and receive responses from it
(this communication is done indirectly, through a Serviceguard API). The
queries are decomposed into categories (of classes) which are serviced by
various providers. The providers gather data from various sources,
including, commonly, the cmclconfd daemons on all connected nodes,
returning data to a central assimilation point where it is filtered to meet
the needs of a particular query.
This daemon is started by inetd(1M). There are entries in the
/etc/inetd.conf file.
This daemon may not be running on your system; it is used only by
clients of the object manager.
Cluster SNMP Agent Daemon: cmsnmpd
This daemon is used by the management-station version of Serviceguard
Manager to obtain information about the cluster. It produces the Cluster
MIB. (For more information about the cluster MIB, go to
http://docs.hp.com -> High Availability and look under
Frequently Asked Questions.) cmsnmpd will only be running if the
/etc/rc.config.d/cmsnmpagt file has been edited to autostart this
subagent. For proper execution, cmsnmpd has to start before the
Serviceguard cluster comes up.
Service Assistant Daemon: cmsrvassistd
This daemon forks and execs any script or processes as 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
cmsrvassistd 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” on page 68.