1. For a network controller in a network control system that manages a plurality of logical networks, a method comprising: receiving a specification of a logical network that comprises a logical router; selecting at least two host machines to implement a routing table for the logical router from a plurality of host machines designated for hosting logical routers, the selected host machines comprising a designated master host machine for the routing table; and generating data tuples for provisioning a set of managed forwarding elements that implement the logical network to send data packets that require processing by the routing table to the selected host machines, wherein the data tuples specify an ordered list of tunnel encapsulations for use by the managed forwarding elements that implement the logical network in order for the managed forwarding elements to send packets to the routing table implemented at the selected host machines with a tunnel encapsulation for a tunnel to the designated master host machine as the first host machine in the specified ordered list.