1. A method comprising: receiving a first set of routing information from a first datacenter and a second set of routing information from a second datacenter, wherein the first and second datacenters are located at two different physical sites, each datacenter comprising a plurality of computing devices that execute a plurality of machines and implement a global logical network that spans the first and second datacenters to connect a subset of the machines executing on the computing devices at the first and second datacenters, said global logical network including a global logical router that spans the first and second datacenters, wherein the first set of routing information is tagged by a first locale identifier that identifies the first datacenter and the second set of routing information is tagged by a second locale identifier that identifies the second datacenter; generating a set of routing instructions based on the first set of routing information and the second set of routing information, wherein the set of routing instructions uses the first locale identifier to identify network resources in the first datacenter and the second locale identifier to identify network resources in the second datacenter; and providing the set of routing instructions to a first set of computing devices in the first datacenter and a second set of computing devices in the second datacenter for jointly implementing the global logical router for performing L3 routing among the subset of machines, the subset of machines comprising a first set of machines of the first datacenter and a second set of machines of the second datacenter.