Methods and apparatus to manage workload domains in virtual server racks are disclosed. An example apparatus includes processor circuitry to, in response to detecting that a number of available physical racks satisfies a threshold number of physical racks, apply a first resource allocation technique by reserving requested resources by exhausting first available resources of a first physical rack before using second available resources of a second physical rack; in response to detecting that the number of available physical racks does not satisfy the threshold number of physical racks, apply a second resource allocation technique by reserving the requested resources using a portion of the first available resources without exhausting the first available resources and using a portion of the second available resources without exhausting the second available resources; and execute one or more workload domains associated with a number of requested resources.