Internet data centers (IDCs) perform multi-customer hosting on a virtualized collection of resources while grid computing generalizes distributed computing by focusing on large scale resource sharing (I. Foster et al., 2001). When we consider the problem of resource allocation, the connection between grid and IDC is obvious. Indeed, both systems use similar resource reservation patterns. Mainly, service level agreement for IDC, and advanced resource reservation in grid systems (J. MacLaren, 2003). In each world, those reservation patterns are deemed to precisely represent resource requirements. This work presents an autonomous system for online resource allocations. The simulated architecture represents some IDC but our problem solving concepts are applicable to grid infrastructures. Our system takes advantage of monitoring information to reconsider its mathematical modelling of the components. This results in a continuous adaptation of the allocated resources.