Generally, callback methods require access to the properties of the resource. The RMAPI provides both shell commands and C functions that you can use in callback methods to access the system-defined and extension properties of resources. See the scha_resource_get(1HA) and scha_resource_get(3HA) man pages.
The DSDL provides a set of C functions (one for each property) to access system-defined properties, and a function to access extension properties. See the scds_property_functions(3HA) and scds_get_ext_property(3HA) man pages.
You cannot use the property mechanism to store dynamic state information for a data service because no API functions are available for setting resource properties (other than for setting Status and Status_msg). Rather, you should store dynamic state information in global files.
The cluster administrator can set certain resource properties using the scrgadm command or through an available graphical administrative command or through an available graphical administrative interface. However, do not call scrgadm from any callback method because scrgadm fails during cluster reconfiguration, that is, when the RGM calls the method.