Fix the ceph warning after upgrade to luminous

Change-Id: Ia94c10ca8292d803bc20650fb1d496002455338f
Closes-Bug: #1771968

ansible/roles/ceph/tasks/upgrade.yml

@@ -33,3 +33,11 @@
   when:
     - enable_ceph_nfs | bool
     - inventory_hostname in groups['ceph-nfs']
+
+# NOTE(chenxing): Disallowing pre-luminous OSDs and enabling all
+# new Luminous-only functionality
+- name: Enabling all new Luminous-only functionality
+  command: docker exec ceph_mon ceph osd require-osd-release luminous
+  delegate_to: "{{ groups['ceph-mon'][0] }}"
+  changed_when: False
+  run_once: True