Cluster manager and SNMP monitoring programs

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A PowerHA® SystemMirror® cluster is dynamic and can undergo various transitions in its state over time.

For example, a node can join or leave the cluster, or another IP label can replace a service IP label on a physical network interface card. Each of these changes affects the composition of the cluster, especially when highly available clients and applications must use services provided by cluster nodes.

SNMP support

The Cluster Manager provides Simple Network Management Protocol (SNMP) support to client applications. SNMP is an industry-standard specification for monitoring and managing TCP/IP-based networks. SNMP includes a protocol, a database specification, and a set of data objects. This set of data objects forms a Management Information Base (MIB). SNMP provides a standard MIB that includes information such as IP addresses and the number of active TCP connections. The standard SNMP agent is the snmpd daemon.

You can extend SNMP to include enterprise-specific MIBs that contain information relating to a discrete environment or application. In PowerHA SystemMirror, the Cluster Manager maintains information about the objects defined in its MIB and passes this information on to a specialized network monitoring or network management station.

PowerHA SystemMirror MIB

The Cluster Manager maintains cluster status information in a special PowerHA SystemMirror MIB. When the Cluster Manager starts on a cluster node, it registers with the SNMP daemon snmpd, and then continually gathers cluster information. The Cluster Manager maintains an updated topology of the cluster in the PowerHA SystemMirror MIB as it tracks events and the resulting states of the cluster.