Managing HP Serviceguard for Linux, Eighth Edition, March 2008

Understanding Serviceguard Software Components
Serviceguard Architecture
Chapter 3 39
Each of these daemons logs to the Linux system logging files. The
quorum server daemon logs to the user specified log file, such as,
/usr/local/qs/log/qs.log file on Red Hat or /var/log/qs/sq.log on
SUSE and cmomd logs to /usr/local/cmom/log/cmomd.log on Red Hat
or /var/log/cmom/log/cmomd.log on SUSE.
NOTE The file cmcluster.conf contains the mappings that resolve symbolic
references to $SGCONF, $SGROOT, $SGLBIN, etc, used in the pathnames in
the subsections that follow. See “Understanding the Location of
Serviceguard Files” on page 142 for details.
Configuration Daemon: cmclconfd
This daemon is used by the Serviceguard commands to gather
information from all the nodes within the cluster. It gathers
configuration information such as information on networks and volume
groups. It also distributes the cluster binary configuration file to all
nodes in the cluster. This daemon is started by the internet daemon,
xinetd(1M).
Parameters are in the /etc/xinetd.d/hacl-cfg and
/etc/xinetd.d/hacl-cfgudp files. The path for this daemon is
$SGLBIN/cmclconfd.
Cluster Daemon: cmcld
This daemon is used to determine cluster membership by sending
heartbeat messages to other cmcld daemons on other nodes within the
Serviceguard cluster. It runs at a real time priority and is locked in
memory. The cmcld daemon sets a safety timer in the kernel which is
used to detect kernel hangs. If this timer is not reset periodically by
cmcld, the kernel will cause a system reboot. This could occur because
cmcld could not communicate with the majority of the cluster’s members,
or because cmcld exited unexpectedly, aborted, or was unable to run for a
significant amount of time and was unable to update the kernel timer,
indicating a kernel hang. Before a reboot due to the expiration of the
safety timer, messages will be written to the syslog file and the kernel’s
message buffer.
cmcld also manages Serviceguard packages, determining where to run
them and when to start them. The path for this daemon is:
$SGLBIN/cmcld.