Refactor: simpify cloud_provider is defined condition

For this change, `cloud_provider` change the default value to empty
string.

Signed-off-by: ChengHao Yang <17496418+tico88612@users.noreply.github.com>

roles/kubernetes/control-plane/templates/kubeadm-config.v1beta3.yaml.j2

@@ -24,7 +24,7 @@ nodeRegistration:
   taints: []
 {% endif %}
   criSocket: {{ cri_socket }}
-{% if cloud_provider is defined and cloud_provider in ["external"] %}
+{% if cloud_provider == "external" %}
   kubeletExtraArgs:
     cloud-provider: external
 {% endif %}

roles/kubernetes/node/templates/kubelet.env.v1beta1.j2

@@ -21,7 +21,7 @@ KUBELET_VOLUME_PLUGIN="--volume-plugin-dir={{ kubelet_flexvolumes_plugins_dir }}
 {% if kube_network_plugin is defined and kube_network_plugin == "cloud" %}
 KUBELET_NETWORK_PLUGIN="--hairpin-mode=promiscuous-bridge --network-plugin=kubenet"
 {% endif %}
-{% if cloud_provider is defined and cloud_provider in ["external"] %}
+{% if cloud_provider == "external" %}
 KUBELET_CLOUDPROVIDER="--cloud-provider={{ cloud_provider }}"
 {% else %}
 KUBELET_CLOUDPROVIDER=""

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

@@ -166,10 +166,9 @@
 
 - name: Check cloud_provider value
   assert:
-    that: cloud_provider in ['external']
-    msg: "If set the 'cloud_provider' var must be set either to 'external'"
+    that: cloud_provider == 'external'
   when:
-    - cloud_provider is defined
+    - cloud_provider
     - not ignore_assert_errors
   tags:
     - cloud-provider