1. A system for managing computing nodes and cooling devices cooling the computing nodes in an infrastructure, the system comprising: one or more managers configured to receive a service request for a workload to be run on one or more of the computing nodes; determine candidate workload placements for placing the workload on the one or more computing nodes; determine a first cost associated with each candidate workload to placements using a computational network model, wherein the computational network model models power consumption of the one or more computing nodes and includes consideration of terms in a service level agreement (SLA); determine a second cost associated with the cooling devices for each candidate workload placement using a thermal network model, wherein the thermal network model models power consumption of devices in the infrastructure, including the cooling devices; minimize a cost function, wherein the cost function determines an economic cost of operating the infrastructure while running the requested workload and wherein the cost function is based upon the first cost, the second cost and an energy price; and select a candidate workload placement from the candidate workload placements based on the minimized cost function.