You provide the definitions of your existing provider implementations to enable the functionality for custom operations, custom hooks, custom notifications, or the custom provisioning process.
In addition you declare if the functions should be called in the context of an operation, hook, notification, custom provisioning process, or as a parameter supplier for a custom parameter.
Your provider definition specifies, what is executed. Custom operations and custom hooks specify the following:
When and under which circumstances your provider definition is executed.
Whether your provider definition is executed on the host or on the instance.