preinstall: etcd group might not exists (#7202)

fixes 8c182122

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

roles/kubernetes/preinstall/tasks/0020-verify-settings.yml

@@ -69,8 +69,7 @@
     that: groups.etcd|length is not divisibleby 2
   when:
     - not ignore_assert_errors
-    - groups.get('etcd')
-    - inventory_hostname in groups['etcd']
+    - inventory_hostname in groups.get('etcd',[])
 
 - name: Stop if memory is too small for masters
   assert:
@@ -274,7 +273,7 @@
     that: etcd_deployment_type in ['host', 'docker']
     msg: "The etcd deployment type, 'etcd_deployment_type', must be host or docker"
   when:
-    - inventory_hostname in groups['etcd']
+    - inventory_hostname in groups.get('etcd',[])
     - not etcd_kubeadm_enabled
 
 - name: Stop if etcd deployment type is not host when container_manager != docker
@@ -282,7 +281,7 @@
     that: etcd_deployment_type == 'host'
     msg: "The etcd deployment type, 'etcd_deployment_type', must be host when container_manager is not docker"
   when:
-    - inventory_hostname in groups['etcd']
+    - inventory_hostname in groups.get('etcd',[])
     - not etcd_kubeadm_enabled
     - container_manager != 'docker'