A Generic Framework Supporting Self-Organisation and Self-Management in Hierarchical Systems

A novel, generic, framework for supporting self-organisation and self-management in hierarchical systems is presented. The framework allows for the incorporation of local self-organising and self-managing strategies at each level in the hierarchy. These local strategies determine the behaviour of that level and the effects of these strategies can be communicated to, and used by, the strategies in adjacent levels of the hierarchy. Thus, in general, strategies may be viewed as parameterised functions. Information emanating from both the lower and the upper levels in the hierarchy can be used as parameters. Information from below represents the status of the lower levels, whereas information from above can be used to influence the direction and the rate of system evolution. As the component parts of the system evolve to their goal states, the rate of evolution slows. At that point, by definition, a component is maximally contributing to the global goal state of the system as a whole. A novel concept to measure the distance that a component is from this stasis, its Suitability Index is presented and formally defined. Although the proposed framework can be generalised to any hierarchical system, this paper applies it specifically to large scale, hierarchically structured, computer systems. An implementation of this framework and an empirical study of its effectiveness has been conducted as part of the the CloudLightning Project.