A centralized namespace controller allocates addresses in a distributed cloud infrastructure on-demand. Upon receiving a request to allocate addresses for a network to be provisioned by a cloud computing system included in the distributed cloud infrastructure, the centralized namespace controller allocates a network address that is unique within the distributed cloud infrastructure. Further, the centralized namespace controller allocates a range of virtual network interface cards (NIC) addresses that are unique within the network. The centralized namespace controller then allocates addresses from the range of virtual NIC addresses on an as-requested basis—when a virtual NIC is being created by the first cloud computing system on the network. Advantageously, by centralizing the allocation of addresses and dedicating independent NIC address ranges to different cloud computing systems, the centralized namespace controller enables stretched L2 networks between cloud computing systems while preventing duplicated addresses on the stretched networks.