System management method and apparatus

System management apparatus for carrying out at least one management task in relation to at least one service intended to be provided by a computer system including cooperating physical and logical entities, said apparatus comprising:

• a declarative model specifying independently of any particular said task, the requirements needing to be met for the service to be available, these requirements being set out in terms of the entities required and the inter-relationships of the required entities, one of said declarative models being provided for the or each said at least one service,
• inference engine means for carrying out inferencing operations in relation to a said declarative model,
• task control means, one of said task control means being respectively provided for the or each said at least one management task, each task control means being arranged for controlling performance of the corresponding task by said inference engine means in a manner independent of any particular said model and in terms of general inferencing operations, and
• means for causing a said at least one management task to be carried out in relation to a said at least one service, said means for causing being arranged for causing said inference engine means to operate on the corresponding declarative model under the control of the said task control means relevant to that management task.