On the root server

You have to tell the Rudder Root server that a node will be a relay. To do so, launch the rudder-node-to-relay script on the root server, supplying the UUID of the host to be considered as a relay. You can find the UUID of your node with the rudder agent info command.

/opt/rudder/bin/rudder-node-to-relay aaaaaaaa-bbbb-cccc-dddd-eeeeeeee