The increasing complexity of computer systems has led to the automation of administration functions, in the form of autonomic managers. Today many autonomic managers are available but they mostly address a specific administration aspect which makes necessary their coexistence for a complete autonomic system management. However, coordinating them is necessary for proper and effective global administration. Such coordination can be considered as a problem of synchronization and logical control of managers actions. We therefore investigate the use of reactive models with events and states, and discrete control techniques to solve this problem. This paper presents an application of the latter approach for coordinating autonomic managers addressing resource optimization, in the perspective of green computing. The managers control server provisioning (self-sizing manager) and CPU frequency (Dvfs manager), and the coordination controller controls the managers actions so as to avoid incoherent management decisions. The coordination controller is designed using synchronous programming and Discrete controller synthesis (DCS) which are well-suited for the design of reactive systems. Experimental results are presented to evaluate the efficacy of the approach.