Rename master to control plane - non-breaking changes only (#11394)

K8s is moving away from the "master" terminology, so kubespray should follow the same naming conventions. See https://github.com/kubernetes/community/blob/65d886bb3029e73d9729e1d4f27422a7985233ed/sig-architecture/naming/recommendations/001-master-control-plane.md

roles/kubernetes/preinstall/tasks/0040-verify-settings.yml

@@ -60,7 +60,7 @@
     - not ignore_assert_errors
     - inventory_hostname in groups.get('etcd',[])
 
-- name: Stop if memory is too small for masters
+- name: Stop if memory is too small for control plane nodes
   assert:
     that: ansible_memtotal_mb >= minimal_master_memory_mb
   when:

roles/kubernetes/preinstall/tasks/0050-create_directories.yml

@@ -15,7 +15,8 @@
     - bootstrap-os
     - apps
     - network
-    - master
+    - master    # master tag is deprecated and replaced by control-plane
+    - control-plane
     - node
   with_items:
     - "{{ kube_config_dir }}"
@@ -39,7 +40,8 @@
     - bootstrap-os
     - apps
     - network
-    - master
+    - master    # master tag is deprecated and replaced by control-plane
+    - control-plane
     - node
   with_items:
     - "{{ kube_cert_dir }}"