cmcld also manages Serviceguard packages, determining where to run them and when to start them.

NOTE: Two of the central components of Serviceguard—Package Manager, and Cluster Manager—run as parts of the cmcld daemon. This daemon runs at priority 20 on all cluster nodes. It is important that user processes should have a priority lower than 20, otherwise they may prevent Serviceguard from updating the kernel safety timer, causing a system reset.

File Management Daemon: cmfileassistd

The cmfileassistd daemon is used by cmcld to manage the files that it needs to read from, and write to, disk. This is to prevent any delays in issuing Input/Output from impacting the timing of cmcld.

Syslog Log Daemon: cmlogd

cmlogd is used by cmcld to write messages to syslog. Any message written to syslog by cmcld is written via cmlogd. This is to prevent any delays in writing to syslog from affecting the timing of cmcld.

Cluster Logical Volume Manager Daemon: cmlvmd

This daemon is responsible for keeping track of all the volume group(s) that have been made cluster aware. When a volume group is made cluster aware, a cluster node can only activate it in exclusive mode. This prevents the volume group from being activated in write mode by more than one node at a time.

Cluster Object Manager Daemon: cmomd

This daemon is responsible for providing information about the cluster to clients—external products or tools that depend on knowledge of the state of cluster objects.

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 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. 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.

Generic Resource Assistant Daemon: cmresourced

This daemon is responsible to set and get the status/value of generic resources configured as part of the package and influence the availability of the package based on the availability of the resource.

42 Understanding Serviceguard Software Components

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HP Serviceguard manual File Management Daemon cmfileassistd, Syslog Log Daemon cmlogd, Cluster Object Manager Daemon cmomd