5.4.5 Exception

Another problem with policies is, just like with any rule in the world, that at a certain moment, exceptions have to be made. They are usually transitional and get incorporated into the mainstream policy itself following a feedback process. On the other hand temporary policies are necessary for stating exceptions to the normal operation. For example: maintenance or changes of a system during normal operation in the IT environment will affect performance policies, because the required quality of service in this area cannot be fulfilled. So the performance policies will take actions or at least generate error events. This management system behaviour is undesirable, because the IT system operates orderly in terms of the maintenance situation. Metapolicies will handle this, because they can control other policies, and for that reason it is easy to create exceptions to prevent the management system from taking unwanted actions.

Policies governing the process of introducing exceptions into the system are also important. For example, who is allowed to sign off exceptions for a certain area or how long will the exception last? The advantage of collecting them in a separate class is that exceptions are explicitly stated and not treated as normal policies. If it is necessary to permanently incorporate the exception into the system, it must be considered at the refinement stage so that it also becomes a policy governing refinement.