When deploying the Controller, it needs to be deployed via a StatefulSet. This is because each Controller instance needs to know which index it is. The Controller can be deployed with:
kubectl apply -f invoker.yml
If you want to increase the number of controllers deployed, then you will also need to update part of the Nginx configuration. First, you will need to update the replication count for the Controllers here.
After updating the controller count, you will need to update the available routes for Nginx. This is because the controllers are not yet purely HA, but are in a failover mode. To update Nginx with the proper routes, take a look at these properties. The routes for the controllers and how they are determined can be found in the StatefulSet docs.