@Gakio's solution did not work in werf yaml template (got the error "range can't iterate over ..."). The following improvement helped:

apiVersion: v1
kind: Service
metadata:
  labels:
    app: some-app
  name: some-service
  namespace: some-namespace
spec:
  ports:
  {{ range untilStep 40000 42000 1 }}   # start stop step
  - port: {{ . }}
    targetPort: {{ . }}
    name: exposed-port-{{ . }}
  {{ end }}
  selector:
    app: some-app
  sessionAffinity: None
  type: ClusterIP