Sun Cluster Data Service for Apache Tomcat Guide for Solaris OS

Understanding Sun Cluster HA for Apache Tomcat Fault Monitor

This section describes the Sun Cluster HA for Apache Tomcat fault monitor's probing algorithm and functionality, states the conditions, messages, and recovery actions associated with unsuccessful probing, and states the conditions and messages associated with unsuccessful probing.

For conceptual information on fault monitors, see Sun Cluster Concepts Guide for Solaris OS.

Resource Properties

The Sun Cluster HA for Apache Tomcat fault monitor uses the same resource properties as the 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 following steps are executed to monitor the sanity of Apache Tomcat.

  1. Sleeps for Thorough_probe_interval.

  2. Pings the Host, which is configured in the Apache Tomcat HA parameter file.

  3. Connects to the Apache Tomcat via Host and Port. If the connection is successful it sends the TestCmd and tests whether the ReturnString comes back. If it fails, it is rescheduled after 5 seconds. If this fails again, then the probe will restart the Apache Tomcat.

    Caution – Caution –

    The ReturnString cannot be Connection refused because this string will be returned if no connection is possible.

  4. If the Apache Tomcat process has died, pmf will interrupt the probe to immediately restart the Apache Tomcat.

  5. If the Apache Tomcat is repeatedly restarted and subsequently exhausts the Retry_count within the Retry_interval, then a failover is initiated for the resource group onto another node. This is done if the resource property Failover_enabled is set to TRUE.