Administrative actions on resources include setting and changing resource properties. The Validate and Update callback methods enable a resource type implementation to hook into these administrative actions.
This optional method is called when a resource is created and when administrative action updates the properties of the resource or its containing resource group. This method is called on the set of cluster nodes indicated by the Init_nodes property of the resource's type. Validate is called before the creation or update is applied, and a failure exit code from the method on any node causes the creation or update to be canceled.
Validate is called only when resource or resource group properties are changed through administrative action, not when the RGM sets properties, or when a monitor sets the resource properties Status and Status_msg.
This optional method is called to notify a running resource that properties have been changed. Update is invoked after an administration action succeeds in setting properties of a resource or its group. This method is called on nodes where the resource is online. The method uses the API access functions to read property values that might affect an active resource and adjust the running resource accordingly.
Failure of the Update method causes the syslog(3) function to generate an error message but does not otherwise affect RGM management of the resource.