Change kubeadm config to run etcd by kubeadm.

roles/kubernetes/master/templates/kubeadm-config.v1alpha1.yaml.j2

-apiVersion: kubeadm.k8s.io/v1alpha1
+apiVersion: kubeadm.k8s.io/v1alpha2
 kind: MasterConfiguration
 api:
   advertiseAddress: {{ ip | default(ansible_default_ipv4.address) }}
@@ -7,6 +7,7 @@ api:
   controlPlaneEndpoint: {{ kubeadm_config_api_fqdn }}
 {% endif %}
 etcd:
+  external:
       endpoints:
 {% for endpoint in etcd_access_addresses.split(',') %}
       - {{ endpoint }}