A method controls resource allocation in a data center. The method comprises identifying a first computational task to be transferred from a first set of one or more servers. The method also comprises identifying a second set of one or more servers to which the first computational task may be transferred, by using the respective current computational load of the second set of servers to determine that the second set of servers has sufficient available computational resources to implement the computational task and identifying network links for transferring the computational task and using the respective transmission loads of the identified links to determine that there is sufficient network capacity to transfer the computational task from the first set of servers to the second set of servers. The method then comprises transferring the computational task from the first set of servers to the second set of servers.