Red Hat OpenShift on OpenStack scaling a MachineSet does not work

Issue

• Scaling a MachineSet manually does not work

  shell$ oc scale --replicas=5 machineset cluster-xxxxx-worker -n openshift-machine-api
  machineset.machine.openshift.io/cluster-xxxxx-worker scaled
  shell$ oc get machinesets -n openshift-machine-api
  NAME                DESIRED   CURRENT   READY   AVAILABLE   AGE
  cluster-xxxxx-worker   5         5         3       3           45m
  

• Additional worker nodes are not beeing created after creating the initial machine set

  shell$ oc get machinesets -n openshift-machine-api
  NAME                DESIRED   CURRENT   READY   AVAILABLE   AGE
  cluster-xxxxx-worker   5         5         3       3           45m
  

• Cluster machine controller reports quota error

  W0310 15:09:36.746133       1 controller.go:321] Failed to create machine "cluster-xxxxx-worker-xphgt": error creating Openstack instance: Create new server err: Request forbidden: [POST https://os-controller.example.intern:13774/v2.1/servers], error message: {
  "forbidden": {"message": "Quota exceeded for ram: Requested 16384, but already used 98304 of 102400 ram", "code": 403}}