Sun Cluster 3.1 Data Services Developer's Guide

Monitor_check Method

The RGM calls the Monitor_check method whenever the PROBE method attempts to fail the resource group containing the data service over to a new node.

This section describes the major pieces of the Monitor_check method for the sample application. This section does not describe functionality common to all callback methods, such as the parse_args function and obtaining the syslog facility, which are described in Providing Common Functionality to All Methods.

For the complete listing of the Monitor_check method, see Monitor_check Method Code Listing.

The Monitor_check method must be implemented so that it does not conflict with other methods running concurrently.

The Monitor_check method calls the Validate method to verify that the DNS configuration directory is available on the new node. The Confdir extension property points to the DNS configuration directory. Therefore Monitor_check obtains the path and name for the Validate method and the value of Confdir. It passes this value to Validate, as shown in the following listing.

# Obtain the full path for the Validate method from
# the RT_BASEDIR property of the resource type.

# Obtain the name of the Validate method for this resource.
VALIDATE_METHOD=`scha_resource_get -O VALIDATE \

# Obtain the value of the Confdir property in order to start the
# data service. Use the resource name and the resource group entered to
# obtain the Confdir value set at the time of adding the resource.
config_info=`scha_resource_get -O Extension -R $RESOURCE_NAME \

# scha_resource_get returns the type as well as the value for extension
# properties. Use awk to get only the value of the extension property.
CONFIG_DIR=`echo $config_info | awk `{print $2}'`

# Call the validate method so that the dataservice can be failed over 
# successfully to the new node.

See the Validate Method to see how the sample application verifies the suitability of a node for hosting the data service.