Rudder

In RUDDER they are few operation missing for the promote node to relay :
In case of failure to promote a node to relay, we want to be able to recover from the inital state of the node and delete all the residuals objects from the promote operation :
- Be able to delete a directive's system (If no such directive, it's a success)
- Be able to delete a PolicyServerTarget (If no such directive, it's a success)