1. A method comprising: at a management application in a first virtual network comprising a first virtual service node, subscribing to virtual network services provided by a second virtual network; sending to the second virtual network a first message comprising information configured to start in the second virtual network a virtual switch that switches network traffic for one or more virtual machines in the second virtual network to extend services provided by the first virtual network into the second virtual network; and sending to the second virtual network a second message comprising information configured to start a second virtual service node in the second virtual network direct network traffic among virtual machines within the second virtual network based on service policies.