Use include/import tasks (#2192)

import_tasks will consume far less memory, so it should be
used whenever it is compatible.

roles/kubernetes/master/tasks/kubeadm-setup.yml

@@ -168,5 +168,5 @@
   when: sa_key_before.stat.checksum|default("") != sa_key_after.stat.checksum
 
 - name: kubeadm | cleanup old certs if necessary
-  include: kubeadm-cleanup-old-certs.yml
+  import_tasks: kubeadm-cleanup-old-certs.yml
   when: old_apiserver_cert.stat.exists

roles/kubernetes/master/tasks/main.yml

@@ -1,5 +1,5 @@
 ---
-- include: pre-upgrade.yml
+- import_tasks: pre-upgrade.yml
   tags:
     - k8s-pre-upgrade
 
@@ -9,7 +9,7 @@
     kube_basic_auth: false
   when: kubeadm_enabled|bool|default(false)
 
-- include: users-file.yml
+- import_tasks: users-file.yml
   when: kube_basic_auth|default(true)
 
 - name: Compare host kubectl with hyperkube container
@@ -56,9 +56,9 @@
     - upgrade
 
 - name: Include kubeadm setup if enabled
-  include: kubeadm-setup.yml
+  import_tasks: kubeadm-setup.yml
   when: kubeadm_enabled|bool|default(false)
 
 - name: Include static pod setup if not using kubeadm
-  include: static-pod-setup.yml
+  import_tasks: static-pod-setup.yml
   when: not kubeadm_enabled|bool|default(false)