Edited the g5k:generate rule of the Rakefile. It now passes clustername/nodes/*.yaml to the generator instead of clustername_generated.yaml.
Also modified lookup() calls in the .rb file of each cluster using:
 for i in $(find . -iname "*.rb"); do name=$(basename $i .rb); sed -i "s/lookup('"$name"_generated', /lookup(node_uid, /g" $i; done