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Oracle® Solaris Cluster Data Service for DHCP Guide

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Updated: September 2015
 
 

Understanding the HA for DHCP Fault Monitor

This section describes the HA for DHCP fault monitor probing algorithm or functionality, states the conditions, and recovery actions associated with unsuccessful probing.

For conceptual information on fault monitors, see the Oracle Solaris Cluster 4.3 Concepts Guide .

Resource Properties

The HA for DHCP fault monitor uses the same resource properties as resource type SUNW.gds. Refer to the SUNW.gds (5) man page for a complete list of resource properties used.

Probing Algorithm and Functionality

The HA for DHCP fault monitor is controlled by the extension properties that control the probing frequency. The default values of these properties determine the preset behavior of the fault monitor. The preset behavior should be suitable for most Oracle Solaris Cluster installations. Therefore, you should tune the HA for DHCP fault monitor only if you need to modify this preset behavior.

  • Setting the interval between fault monitor probes (Thorough_probe_interval)

  • Setting the timeout for fault monitor probes (Probe_timeout)

  • Setting the number of times the fault monitor attempts to restart the resource (Retry_count)

The HA for DHCP fault monitor checks within an infinite loop. During each cycle the fault monitor will perform a check and report either a failure or success.

If the fault monitor is successful it returns to its infinite loop and continues the next cycle of probing and sleeping.

If the fault monitor reports a failure a request is made to the cluster to restart the resource. If the fault monitor reports another failure another request is made to the cluster to restart the resource. This behavior will continue whenever the fault monitor reports a failure.

If successive restarts exceed the Retry_count within the Thorough_probe_interval a request to failover the resource group onto a different node is made.

DHCP Probe

Test whether PNM (Public Network Monitoring) has changed the active interface for the network that DHCP is using. If this fails, then the probe will restart the DHCP resource.